Dietary Guidelines Advisory Committee Meeting
Sponsored by the
U.S. Department of Health and Human Services (HHS)
U.S. Department of Agriculture (USDA)
Held at the
Hotel Washington
Washington, DC
January 28-29, 2004
Meeting Summary
Wednesday, January 28
(8:40 a.m.)
Participants
Dietary Guidelines Advisory Committee: Dr. Janet C. King
(Chair), Dr. Lawrence J. Appel, Dr. Yvonne L. Bronner, Dr. Benjamin
Caballero, Dr. Carlos A. Camargo Jr., Dr. Fergus M. Clydesdale, Dr.
Vay Liang W. Go, Dr. Penny M. Kris-Etherton, Dr. Joanne R. Lupton, Dr.
Theresa A. Nicklas, Dr. Russell R. Pate, Dr. F. Xavier Pi-Sunyer, Dr.
Connie M. Weaver
Executive Secretaries: Ms. Carole Davis, Ms. Kathryn McMurry,
Dr. Pamela Pehrsson, Dr. Karyl Thomas Rattay
Others: Dr. Cristina Beato, Dr. Eric Hentges
Welcome and Introduction of the Committee
Dr. Cristina Beato, Acting Assistant Secretary for Health, HHS,
welcomed participants to the second meeting of the 2005 Dietary
Guidelines Advisory Committee (DGAC). She noted that since the
last meeting in September 2003 the Committee has reviewed recent
scientific literature pertaining to the key areas of the Dietary
Guidelines.
Dr. Beato thanked the members of Committee for volunteering their
valuable time and services to assist HHS and USDA. She
acknowledged the importance of public input to this process and noted
that the Committee had received a wide range of comments prior to this
meeting. Dr. Beato invited additional written comments from the
public and reviewed the procedures for submitting such comments.
She noted that respondents should be clear and concise and provide the
scientific justification for their views. All comments from the
public must be sent to the full committee, using the address in the
Federal Register.
Dr. Beato concluded by again thanking the members and the staff for
their hard work and gave them her best wishes for a productive
meeting. She then turned the floor over to Dr. King.
Dr. Janet C. King, Chair, Dietary Guidelines Advisory Committee,
noted that the Committee has undertaken a challenging task in the
short time since the first meeting. The goal of this meeting is
for the full Committee to review the work of the various subcommittees
and identify priority issues. At the next DGAC meeting (March
2004), the Subcommittees will present their draft recommendations,
with scientific rationale. The Committee will work toward
consensus on which recommendations to include in the report. The
full Committee will review the draft DGAC report to the Secretaries at
the fourth and final DGAC meeting (May 2004). The final report
will be submitted to the HHS and USDA Secretaries in June 2004.
Dr. King introduced Dr. Carol Suitor, a scientific writer formerly
with the Institute of Medicine (IOM), who will prepare the draft
report. Dr. Suitor was also involved in the last DGAC report.
Dr. King summarized the work of the Committee to date. Since
the last meeting (September 2003), the DGAC Subcommittees and staff
have been working to identify priority research questions, conduct
literature reviews, identify key scientific findings, and identify
outside experts to address important issues. The Subcommittees
also identified overarching topics for consideration by the full
Committee. Dr. King noted that the Subcommittees would present
their findings on the second day of the meeting.
Dr. King then reviewed the agenda for the day. In the morning
session, the Committee would hear an update on the Food Guide Pyramid
reassessment process, followed by three expert presentations on
components of a healthy American diet. The afternoon session
would include an expert presentation on nutritional needs of the
elderly, public oral testimony, and a general discussion of
overarching issues.
Food Guide Pyramid Reassessment Update
E. Hentges
Dr. Eric Hentges, Director, Center for Nutrition Policy and
Promotion, USDA, provided an update on the reassessment of the
Food Guide Pyramid. He noted that food guidance at USDA dates
back to 1916 and has taken a number of forms over the years. The
Food Guide Pyramid, which was introduced in 1992, is the current food
guidance at the USDA and is widely recognized. A reassessment of
the Food Guide Pyramid is currently underway to ensure that it
reflects the latest standards in nutrition and to increase consumer
use of the Pyramid.
Dr. Hentges noted that his presentation would focus on comments
received in response to a notice of proposed changes to the Pyramid
that appeared in the Federal Register last September. The
notice included proposed food intake patterns, the background data
from which the patterns were developed, and key issues for public
comment.
Dr. Hentges thanked respondents for taking the time to review the
extensive data in the Federal Register
notice and providing their input. USDA received 255 letters in
response to the notice, containing 1101 separate comments.
Respondents included health and nutrition professionals, health
associations, the food industry and trade associations, government
agencies, and the general public.
USDA asked for specific input in five areas. The first was the
appropriateness of using sedentary, reference-sized individuals in
assigning target energy levels for the proposed food intake patterns.
The proposed energy level used the estimated energy requirement
equation in the Dietary Reference Intake (DRI) Macronutrient Report.
The proposal to use sedentary energy levels was based on the fact that
64 percent of the U.S. population is overweight or obese. This
issue elicited numerous comments. Most respondents supported the
proposed position, although some suggested using an energy level that
reflects a physically active lifestyle. Quite a few respondents
stressed the need to promote physical activity and to include food
patterns for active individuals.
The second topic for public comment was the appropriateness of the
nutritional goals for the daily food intake patterns and the standards
used to set those goals. The adequacy goal for most nutrients
was based on the DRI, the Recommended Daily Allowance (RDA), where one
was available, and the Adequate Intake level (AI) or Acceptable
Macronutrient Distribution Range (AMDR) from the IOM Macronutrient
Report, along with the moderation goals from the 4th and 5th
editions of the Dietary
Guidelines, or Daily Values set by the Food and Drug
Administration (FDA) for the Nutrition Facts Labels.
Many respondents supported the use of these standards, although
some questioned why Estimated Adequate Requirements (EARs) were not
used. Some comments received were in regards to specific
nutrients relative to a nutritional standard, including the following
concerns:
- Vitamin E: Respondents noted that the proposed food
patterns do not meet the new standard for vitamin E. They also
asked whether the standard is appropriate and whether the current
nutritional database was up to date regarding vitamin E.
-
Iodine and Vitamin D: Respondents asked why these nutrients
were not included in the proposed food patterns. (Dr. Hentges
noted that there is an RDA for these nutrients, but information is
lacking in the nutrient database.)
- Sodium and Potassium: Respondents asked what standards were
used, or should be used, for these nutrients. (Dr. Hentges
stated that USDA is awaiting the findings of the IOM Water and
Electrolytes panel.)
- Trans fats: Respondents asked why there was
no goal for trans fats. (Dr. Hentges noted the DRI states they
should be "as low as possible" but does not set a quantitative goal on
which to base a recommendation.)
- Fats: Respondents questioned whether there was good reason
to limit fats to 30 or 35 percent of calories, once you have taken
care of saturated fat.
- Carbohydrates: Respondents suggested using the lowest
percentage within the AMDR range as opposed to a median or other goal
for carbohydrates.
- Fiber: Some thought the proposed goal was too high; others
thought it was too low. (USDA is seeking the Committee's input to set
the appropriate standard.)
- Added sugars: Respondents thought the proposed level was
too high and that the term "goal"implied that added sugars are needed.
(Dr. Hentges noted that the DRI level was a limit, not a goal.)
The third issue for public comment was the appropriateness of the
proposed food intake patterns. This issue elicited more comments
than any other topic. Dr. Hentges noted that the proposed food
groups and patterns were based on nutrient adequacy and typical food
choices. Respondents questioned whether the proposed patterns
were appropriate for educating Americans about healthful eating.
The most common recommendations were that whole grains should be
emphasized; types of fats should be differentiated; and foods in the
Meat and Beans group should be differentiated. There was broad
support for the proposed changes in the food patterns that emphasized
unsaturated fats and oils and greater consumption of whole grains,
legumes, and dark green vegetables. Additional suggestions
included:
- Emphasize nutrient-dense choices for fruits and vegetables and
other groups that are typically under-consumed
- Greater encouragement of legume consumption
- Include fortified soy products in the milk group
- Decrease grain servings
- Keep meat servings as is because meats are leaner now
- Move potatoes to another food group
- Increase the amounts recommended in the milk group
- Include fortified foods or supplements in the food patterns.
The fourth issue for public comment was whether the amounts to be
eaten should be expressed in household measures, such as cups and
ounces, or whether it should continue to be expressed in terms of
number of servings per day. There was widespread support for
replacing servings with household measures in consumer materials.
Some respondents suggested keeping the term "serving," but clarifying
or changing serving sizes. Many respondents noted that the
USDA's food guidance should be in harmony with the Nutrition Facts
label. Dr. Hentges stated that USDA would be meeting with FDA to
ensure this happens.
The fifth issue for public comment was the selection of appropriate
subsets of the food patterns for use in consumer materials. Most
respondents supported the idea of selecting subsets of the proposed
patterns to target various audiences, but the recommendations varied
widely as to what these subsets should be. Dr. Hentges noted
that this issue would be addressed in ongoing consumer testing.
Respondents to the Federal Register notice raised a number
of additional issues, such as comments on water, recommendations to
include physical activity in the food guidance, suggestions for
including supplements in the food patterns, and requests to include
food patterns for vegetarians. Although the
Federal Register notice specifically requested comments on
updating the scientific basis, many people suggested changes in the
graphic design.
Dr. Hentges stated that USDA was pleased with the large number of
responses, the diversity of audiences, and the range of viewpoints
that were expressed. Areas of widespread agreement included the
importance of energy levels and nutritional goals; support for greater
emphasis on whole grains, unsaturated fats, and nutrient-dense
choices, especially from groups that are currently under-consumed; and
the use of standard household measures.
A number of issues will require further discussion, including
whether the vitamin E standard is appropriate; whether nuts should be
placed in a separate food group; whether legumes should be left in
both the Meat and Bean group and the Vegetable group; whether soft
margarines should be classified as oils or moved to solid fats, in
light of trans fat; whether calcium-fortified soy products
should continue to be classified as legumes; and the question of water
and whether it should be included in the pyramid revision. CNPP
will seek the Committee's input and guidance in these areas.
Dr. Hentges noted that the revision of the food guidance is still a
work in progress. The comments provided some clear directions,
but CNPP staff will continue to analyze and revise the technical
basis. Nothing will be finalized until the Committee has
completed its deliberations. CNPP will incorporate new standards the
Committee may set and input it may provide relative to any of the
issues discussed. Dr. Hentges stressed that the implementation
of the
Dietary Guidelines and the Food Guide Pyramid must be
coordinated between all agencies and with many other partners.
CNPP looks forward to discussions on strategies for that
implementation.
Dr. Hentges presented two tables of data that showed the proposed
recommendations versus the current average consumption. While
the proposed recommendations are not that different from current
consumption when looking at the major food groups, there are major
differences within the vegetables, grains, and fats subgroups. The
proposed patterns would require a three- to four-fold increase in
consumption of dark green vegetables. They would also require
consumers to double their consumption of orange vegetables and legumes
and triple their consumption of whole grains. Additionally, the
proposed patterns would require a 30 to 60 percent decrease in
consumption of starchy vegetables, and a 50 to 60 percent decrease in
solid fats.
Dr. Hentges stated that the food patterns would be finalized as
soon as the Committee completes its technical report. Design
aspects will continue until just prior to the release of the revised
food guide, next year (2005). Consumer research has been
underway for approximately two years and will continue through the
implementation of the new guidance. Public comments will be
solicited throughout the process. CNPP will publish a Federal
Register
notice in late spring or early summer to solicit input regarding
consumer messaging and graphic issues. The revised food guide
will be released in 2005, following the release of the official
Dietary
Guidelines.
Dr. Hentges acknowledged that the proposed guidance expects
Americans to make significant behavioral changes. He assured the
Committee that USDA is committed to providing the public with guidance
to help meet this challenge. He stressed that addressing current
issues of overweight and obesity will require partnerships between the
federal agencies, between nutrition educators, dieticians, and
extension educators, and between federal agencies and industry.
Discussion
Dr. King asked whether the current Food Guide Pyramid includes
specific recommendations for intake of whole grains. Dr. Hentges
replied that the Pyramid gives a range of 6-11 servings of grains per
day and recommends at least 3 servings of whole grains. While
this is half of the total grains servings at the lower end of the
range, the proportion decreases as the number of servings increases.
Dr. Caballero noted that there seems to be a general consensus that
a certain level of activity is an essential component of energy
balance. He expressed concern that it would be confusing to base
the food guidance on sedentary people while recommending that people
be more active and asked whether it might not be better to base the
energy level on certain minimal level of physical activity that most
people should try to achieve.
Dr. Hentges noted that most of the health groups that responded
felt that the energy level should reflect the reality that most of the
population is sedentary and overweight. He thought it would be
important to promote more active levels and stated that the Physical
Activity Coefficients could be used to adjust the recommended food
patterns for more active groups. Dr. Hentges emphasized that
CNPP is looking to the Committee for guidance in this area.
Dr. Appel asked for details regarding proposed alternatives to the
Pyramid. Dr. Hentges stated that most of the respondents
suggested rearranging elements within the current shape to emphasize
different issues.
Dr. Clydesdale asked if USDA would be conducting consumer
research regarding the issue of aligning the recommended
serving size with the Nutrition Facts label. Dr.
Hentges stated that CNPP recognized the need for these to be
in harmony and is setting up a meeting with FDA. He
noted that "serving" and "portion" mean the same thing to
consumers and that "value sizing" is an economic phenomenon.
That issue will be addressed in message testing.
Dr. Weaver noted that some comments suggested that nutrient density
should be shown more clearly on food labels, and she stated that the
Committee would pursue that as an overarching issue. Dr. Hentges
noted that many nutrient-dense foods in the proposed patterns are
currently under-consumed. It will be important to identify
strategies to get the desired behavior change.
Referring to the question of soft margarines, Dr. Kris-Etherton
noted that the food industry is making an effort to get rid of
trans fat. In light of that, she wondered if it would be
possible to rethink that category. Dr. Hentges replied that the
previous food pattern was 60% solid fat and 40% oils. The new
recommendation shifts that to 60% oils and 40% solid fat. USDA is
looking to the Committee for guidance in this area. They are
also awaiting recommendations from the IOM as to how trans fat
and saturated fats will be handled in nutrition labeling.
Dr. Nicklas asked if the comments regarding fiber specified certain
age groups. Dr. Hentges and his staff believed the comments were
more generalized, but they would look into it.
Dr. Lupton noted that those at the low end of the energy scale need
to be very careful about the nutrient density of their foods and may
not have many discretionary calories available. She wondered if a
decreased intake of added fat or added sugars could be recommended for
these groups. Dr. Hentges stated that CNPP recognizes the need
for flexibility. The revised Pyramid will reflect the
Committee's guidance on total fat consumption and added sugars.
Dr. Camargo asked if it would be possible to develop two graphics
one for sedentary individuals, and a second for those who meet the
recommended physical activity goal. Dr. Hentges replied that the
challenge is to come out with appropriate food guidance and to make it
relevant to individuals. The greatest challenge in implementing
the revised Pyramid will be connecting with individuals once they are
motivated, which may take a number of targeted tools.
Partnerships will also be critical to implementation.
Dr. Camargo also asked where alcohol fits into the Pyramid.
Dr. Hentges stated that USDA awaits the Committee's input with regard
to the question of alcohol.
Dr. Pate noted that the last DGAC began to address the issue of
integrating dietary and physical activity recommendations. He
stated that this Committee might need to decide how to bring together
the two sets of recommendations.
Dr. Bronner asked whether the new Food Guide Pyramid will state
clearly that people need to make the best choices within each food
group in order to meet the nutrient requirements. Dr. Hentges
replied that it will take a targeted education effort to get consumers
to make the behavior changes that will result in more nutrient dense
choices in food groups that are currently under-consumed. The
food industry can make some changes independent of changes in consumer
behavior, but partnerships will be important.
Dr. Weaver commented that it would be relatively easy to develop a
computerized program that would translate the twelve proposed food
patterns into a customized Pyramid. Dr. Hentges agreed that
interactive tools present an important opportunity for implementing
the revised Pyramid and noted that USDA has already begun to explore
this option.
Dr. Caballero expressed concern that consumers may not understand
that the Pyramid recommendations are based on the lowest fat and
healthiest type of food in each category and that choosing other foods
could affect the energy balance. Dr. Hentges agreed that it
would be important to focus education and consumer testing on
communicating the energy issue. He stated that previous
communications dealt more with the nutrient adequacy of food choices.
This time around, it will be essential to emphasize calorie content.
Dr. Nicklas noted that physical activity is indirectly reflected in
the current Food Guide Pyramid in the range of servings for various
caloric levels. She noted that the Nutrient Adequacy
Subcommittee would be looking into whether nutrient density can be
quantified in a way that is meaningful to consumers.
Dr. Kris-Etherton asked whether it would be feasible to suggest
more nuts in the diet to increase vitamin E intake. Dr. Hentges
noted that it would require a ten- to twenty-fold increase in the
current consumption of nuts in order to obtain a meaningful level of
vitamin E. However, USDA will continue to look at the nutrient
databases, the DRI recommendation, and the feasibility of recommending
increased intake of nuts. (Dr. Weaver noted that the Nutrient
Adequacy Subcommittee would address that issue in its report.)
Dr. Clydesdale asked whether fortification and/or the addition of
vitamin E to foods as an anti-oxidant had been taken into
consideration as part of the consumption. Dr. Hentges stated
that USDA is reviewing the database to see if it accurately reflects
all of the current foods as purchased and available.
Dr. Appel asked whether the title of the document and the Committee
could be changed to the "Dietary and Physical Activity Guidelines."
Dr. Rattay stated that the Congressional mandate refers to the
document as the Dietary Guidelines and that the name would have
to be changed through Congress. Dr. Appel noted that perhaps the
name change could be one of the Committee's recommendations.
Dr. Pate agreed that it seems appropriate to look for ways to draw
together the physical activity and dietary guidance, because it is
difficult to make energy intake recommendations without considering
activity level. However, he recognized that the physical
activity guidelines could be as detailed and extensive as the Dietary
Guidelines being considered by this Committee, and that it
might be difficult to combine all of that information.
Dr. Kris-Etherton noted that the American Heart Association and
others have recommended increased fish consumption and asked if the
revised food guide would do so. Dr. Hentges said there would
need to be a strong reason to emphasize an individual food within a
group.
Dr. King asked what percent of Americans currently selects a diet
that adheres to the Food Guide Pyramid and wondered how to motivate
those Americans who do not to make the necessary changes.
Dr. Hentges acknowledged this would be a challenge. Most
consumers recognize the Pyramid and have a good understanding of the
messages, yet implementation is very low. On the other hand, the
increased selection of herbal products on grocery shelves and the
popularity of diet books indicate that people want to make a change.
The new Dietary Guidelines, followed by the new food
guide and changes in the food labels, present a huge opportunity to
connect with consumers. It will be important not to miss that
opportunity.
Dr. Clydesdale suggested that the recommendations could be promoted
on the basis of the scientific evidence behind them. Dr. King
noted that there is a lot of competition when it comes to guidance on
health and nutrition.
Dr. King thanked Dr. Hentges for an excellent presentation that
showed that the work of this Committee is also going to be important
to the development of the Food Guide Pyramid.
(Break: 9:50-10:05)
Presentations and Discussion: Components of a
Healthy American Diet
F. Hu, R. Krauss, J. Slavin
Dr. King welcomed the three panelists who were invited to
share their expertise with the Committee. She noted that the
panelists would give their presentations, and would be followed with a
discussion between the panel and the full Committee.
Dr. King then introduced the panelists. Dr. Frank Hu is Associate
Professor of Nutrition and Epidemiology in the Department of Nutrition
at Harvard School of Public Health. His research is primarily
focused on the role of diet and lifestyle determinates in the
development of type 2 diabetes and cardiovascular disease. Most,
though not all, of his research is based on two large ongoing cohort
studies at Harvard: the Nurses Health Study and the Health
Professionals Follow-Up Study.
Dr. Ronald Krauss is Director of Atherosclerosis Research at
Children's Hospital Oakland Research Institute. He is a Guest
Senior Scientist in the Genome Sciences Division of Lawrence Berkeley
National Laboratory, and Adjunct Professor in the Department of
Nutritional Sciences at the University of California at Berkeley.
Dr. Krauss has been Senior Advisor to the National Cholesterol
Education Program and is actively involved in the American Heart
Association, having served as Chairman of the Nutrition Committee.
He is founder and Chair of the American Heart Association's Council on
Nutrition, Physical Activity and Metabolism. His research
focuses on genetics, dietary and hormonal effects on plasma
lipoproteins and coronary disease risk.
Dr. Joanne Slavin is Professor of Nutrition at the University of
Minnesota. She is an expert in the areas of nutrition across the
lifestyle, human nutrition, sports nutrition, dietary fiber, and the
role of diet in disease prevention. Her research interests are
dietary fiber, phytoestrogens from flax and soy, and whole grains,
with a focus on conducting human feeding studies that measure relevant
biomarkers for chronic disease prevention.
Dr. Frank Hu, Harvard School of Public Health,
noted that he was asked to speak on four very complicated topics:
Alternate Healthy Eating Index; the balance of n-6 and n-3
polyunsaturated fatty acids in the diet; fat and obesity; and the
foundation of a healthy diet.
Dr. Hu began with a discussion of the Healthy Eating Index (HEI),
which was developed by Eileen Kennedy at USDA in 1995 to assess the
degree of adherence to the Dietary Guidelines for Americans and
the Food Guide Pyramid. The index includes 10 different
components: grains, vegetables, fruits, milk, meat, total fat,
saturated fat, cholesterol, sodium, and variety in the diet. It
has been widely used to monitor dietary quality over time in the U.S.
and to assess dietary quality in different populations. However,
it has not been evaluated in terms of whether it can predict disease
risk, especially cardiovascular disease and cancer.
A study conducted in 2000 examined the relationship between the HEI
and the risk of major chronic disease (cardiovascular disease and
cancer), using the large cohorts in two ongoing studies at Harvard
(nurses and health professionals). Subjects in the two cohorts
were classified according to HEI quintile (multivariate-adjusted) to
determine if there was any association between diet and relative risk
of major chronic disease. The data showed a modest inverse
association between diet and relative risk in men, but no significant
association between diet and risk in women. In light of these
findings, the researchers thought the index should be improved because
it did not predict major chronic disease in the two cohorts.
The researchers proposed an Alternate Healthy Eating Index (AHEI)
to reflect different types of fats; the level of cereal fiber (to
represent whole grain intake); the ratio of white meat to red meat in
the diet; consumption of nuts, legumes, and soy; and moderate alcohol
consumption. They predicted that this index would be a stronger
predictor of major chronic disease than the original HEI. In
fact, they found a strong universal association between HEI, the AHEI,
and major chronic disease in men, as well as a significant universal
association between the AHEI and major chronic disease in women.
Dr. Hu presented a table summarizing percent risk reduction
associated with the highest quintiles of the HEI and the AHEI.
For men, the HEI was associated with 11 percent decrease in incidence
of major chronic disease, and about 28 percent decrease in incidence
of cardiovascular disease. The AHEI was associated with a 20
percent decrease in major chronic disease and a 39 percent decrease in
cardiovascular disease. These findings were significant.
The results for women were especially dramatic. The HEI
predicted no significant risk reduction for women (3 percent reduced
risk for major chronic disease, 14 percent for cardiovascular
disease). The AHEI, however, predicted an 11 percent decrease in
risk of major chronic disease and a 28 percent decrease in risk of
cardiovascular disease. These results were significant.
This research suggests that the AHEI is a better predictor of major
chronic disease than using HEI. Further research is needed to
identify dietary patterns associated with different types of cancer
risk, because neither the HEI nor the AHEI predict this risk.
Dr. Hu recommended that the Dietary Guidelines should continue
to be evaluated for their ability to reduce risk of chronic diseases
that are of major public health concern.
Dr. Hu then turned to a discussion of the relationship between n-6
polyunsaturated fat (n-6 PUFA) and cardiovascular disease, diabetes,
and cancer. He briefly reviewed four randomized clinical trials
with coronary endpoints. The fat intake for subjects in these
studies was 34 to 46 percent of energy. n-6 PUFA was much higher
(10 to 20 percent of energy) than the average American diet. The
results of these clinical trials consistently showed a significant
reduction of serum LDL cholesterol levels and incidence of
cardiovascular events.
The findings of observational studies of the relationship between
n-6 PUFAs and coronary heart disease have also been studied. A
review of 90,000 women in the Nurses' Health Study showed a strong
inverse association between median intake of n-6 PUFAs and relative
risk of both fatal and non-fatal coronary heart disease.
Dr. Hu noted that there have been several studies, which have
examined the effects of n-6 PUFAs on type 2 diabetes. Several
controlled metabolic trials support the benefits of substituting
linoleic acid for saturated fat in improving insulin sensitivity.
The Nurses' Health Study also showed a significant inverse association
between median intake of n-6 PUFAs and relative risk of type 2
diabetes.
Dr. Hu stated that one concern with n-6 PUFA is its potential
effect on cancer, because high polyunsaturated fat has been found to
promote tumor growth in animal studies. However, analysis of
twelve major prospective cohort studies found no evidence that high
polyunsaturated fat intake is associated with tumor growth. Based on
the epidemiological studies, there is no suggestion of increased
breast cancer risk with high n-6 PUFA consumption.
Dr. Hu noted that some people are concerned that a high level of
n-6 PUFAs may mitigate the benefits of n-3 PUFAs. They suggest
reducing n-6 PUFAs to maximize the benefits of n-3 PUFAs, and some
have proposed that the ratio is more important than the absolute
amount of n-6 and n-3. Dr. Hu stated that the evidence suggests
that both n-6 and n-3 are important, that high intake of n-6 does not
mitigate the benefits of n-3, and that the benefits may be additive.
Alpha-Linolenic acid (ALA) is the main source of n-3 PUFAs in the
diet, primarily from plant-based foods. A review of the Nurses'
Health Study found that both ALA and linoleic acid (LA) were
associated with significant decreased risk of fatal coronary heart
disease and that the ratio was not associated with risk. A
higher amount of n-6 PUFAs does not appear to mitigate the benefits of
ALA or fish n-3 fatty acids. Therefore, Dr. Hu recommended that
rather than decreasing n-6 PUFA intake, nutritional strategies should
maximize the benefits of both types of fatty acids through a modest
increase in n-6 and a more dramatic increase in n-3.
Dr. Hu noted that in 1989, the Diet and Health Committee of the
National Academy of Sciences concluded that, "Intake of total fat per
se, independent of the relative content of different types of fatty
acids, is not associated with high blood cholesterol levels and
coronary heart disease." Subsequent studies have shown that the type
of fat is in fact more important than the total amount of fat in the
diet.
Guidelines issued in 2001 by the National Cholesterol Education
Program allow 25 to 35 percent of energy from total fat. The
2002 IOM Macronutrient Report recommended 20 to 35 percent of energy
as an acceptable range but did not set an upper limit for total fat.
The 2000 Dietary Guidelines recommend an upper limit of 30
percent of energy from fat.
A major concern today is the high incidence of obesity. A
low-fat diet has been promoted for weight loss and prevention of
obesity, and conventional wisdom holds that the more fat you eat, the
more likely you are to become obese. However, the evidence does
not support the conventional wisdom.
Short-term studies show that all types of diet will lead to weight
loss if calories are reduced. Long-term studies provide more
valuable information because they show whether a diet can be followed
over the long run and whether it can be used to maintain weight loss.
Sixteen long-term studies (six to eighteen months in duration) found
no evidence that a low-fat diet is more beneficial than a control
diet. Reducing the percent of dietary energy from fat causes a
small short-term reduction in weight, but there appears to be little,
if any, relation between dietary fat composition over the range of 18
to 40 percent of energy and body fat.
Dr. Hu stated that studies conducted in the past three years have
found a moderately high-fat diet that includes nuts and olive oil to
be more beneficial in terms of adherence, weight loss, and weight
maintenance, while also reducing cardiovascular risk factors.
Dr. Hu stated that the exclusive focus on dietary fat has been a
distraction in efforts to control obesity and that the proliferation
of low-fat products has led to increased consumption of refined
carbohydrates. While it is difficult to draw a correlation
between the decrease in fat intake and the increase in obesity, there
is reason to be concerned about this dietary trend.
Dr. Hu suggested that the foundation of a healthy diet should be
food-based, not nutrient-based. There is evidence supporting the
benefits of plant-based foods. He proposed revising the base of
the Food Guide Pyramid to include three food groups fruits and
vegetables, whole grains, and nuts and legumes in light of the
strong evidence that these foods have benefits for cardiovascular
disease and cancer. He recommended placing the entire Pyramid on
a base of physical activity.
Dr. Ronald Krauss, Children's Hospital Oakland Research
Institute, discussed the role of the carbohydrate to fat ratio and
disease risk, the interaction of this ratio with the effects of
individual fatty acids on disease risk, and the relationship of the
carbohydrate to fat ratio to body weight, including maintenance and
weight loss.
He began with several caveats. First, most of the evidence
regarding the disease effects of carbohydrate to fat ratio is derived
from epidemiological and observational studies because it is difficult
to address disease endpoints through clinical trials.
Intermediate cardiovascular disease and diabetes risk biomarkers are
imperfect predictors of clinical disease. Second, the effects of
specific types of carbohydrates and the food sources of those
carbohydrates can vary as much as the effects of individual fatty
acids. Finally, the impact of this ratio on disease and disease
markers is strongly influenced by energy balance.
Dr. Krauss presented a table showing fat to carbohydrate ratios at
various levels of protein intake (15 to 30 percent of calories, in
five percent intervals). For each protein level, he calculated
fat and carbohydrate ratios compatible with the IOM AMDRs. He
then looked at published information through 2002 that related these
ratios to disease and disease risk markers with particular focus on
lipids and lipoproteins since they have a strong predictive value for
cardiovascular outcomes.
Two relationships with lipids were very clear in the studies he
reviewed: an increase in HDL cholesterol as fat is increased,
and a reduction in triglyceride as fat is increased. These
findings were highly consistent in many short-term observational and
clinical trials.
The most predictive measure for cardiovascular outcomes is the
ratio of total to HDL cholesterol. The studies that Dr. Krauss
reviewed showed a significant reduction in this ratio as fat level
increased in the diet. This raises interesting issues for
dietary recommendations regarding fat.
A meta-analysis conducted last year of more than 100 studies found
a strong positive effect of saturated fat on both HDL and LDL
cholesterol, such that the total to HDL cholesterol ratio is minimally
affected by saturated fat. Both mono- and poly-unsaturated fats
were associated with reductions in LDL. Monounsaturated fat
appears to be driving the inverse relationship between fat and lipid
levels, since it is the primary unsaturated fat in the diet.
Dr. Krauss examined disease outcome data from observational studies
of omega-3 fatty acids and lipid levels. These studies found a
strong inverse relation between intake of omega-3 fatty acid in the
form of ALA and triglyceride levels. Another metabolic feature
of these fatty acids is their effect on insulin sensitivity. Dr.
Krauss reviewed a study that compared a diet high in saturated fats, a
high carbohydrate diet, and a Mediterranean Diet. The study
found improved insulin sensitivity on the Mediterranean Diet that was
comparable to that achieved with a higher carbohydrate diet.
Summarizing the effects of carbohydrate and fat on metabolic risk,
Dr. Krauss noted that:
- Higher ratios lower HDL cholesterol and increase triglyceride
and total to HDL cholesterol
- Saturated fatty acids increase LDL and HDL cholesterol and reduce
insulin sensitivity, with no significant change in the total to HDL
cholesterol ratio, as compared to cis-monounsaturated fats and
polyunsaturated fats; these effects are greater for myristic and
palmitic acids than for stearic acids
- Cis- monounsaturated and n-6 polyunsaturated fatty acids reduce
total/HDL cholesterol ratio
- N-3 polyunsaturated fatty acids reduce triglycerides.
With regard to the question of whether the ratio of carbohydrate to
fat modifies the metabolic response to individual fatty acids, Dr.
Krauss stated that higher-fat, lower-carbohydrate diets should be
considered in the context of moderate to higher protein levels,
including more extreme diets that are relatively low in carbohydrate
and high in fat and protein.
To assist the Committee in understanding the impact of these more
extreme ratios on responsiveness to dietary fatty acids, Dr. Krauss
presented data from an unpublished study that he presented last year
to the American Heart Association. This three-year study looked
at the effects of saturated versus unsaturated fat on weight loss.
All subjects followed a baseline diet for one week after which they
were randomly assigned to four groups:
- Basal (Control Diet): 54% carbohydrate, 30%
fat (7% saturated, 13% monounsaturated), 16% protein
- Moderate Carbohydrate Diet: 39% carbohydrate, 31% fat (6%
saturated, 13% monounsaturated), 29% protein
- Lower Carbohydrate/Higher Saturated Fat: 26% carbohydrate,
45% fat (15% saturated, 20% monounsaturated), 29% protein
- Lower Carbohydrate/Lower Saturated Fat: 26% carbohydrate,
46% fat (9% saturated, 27% monounsaturated), 29% protein
This study presented an opportunity to examine the interaction of
fatty acid composition at the same level of carbohydrate and total
fat. To allow researchers to examine the effect of weight loss
on metabolic responses, the study was conducted in three phases:
a one-week pre-weight loss phase, with all subjects on the control
diet; a five-week weight loss phase, and a four-week post-weight loss
phase to stabilize weight.
At the end of the study, the lower carbohydrate/lower saturated fat
diet showed the most significant levels of LDL reduction both pre- and
post-weight loss. There was no significant change in LDL
cholesterol on the moderate carbohydrate diet or the lower
carbohydrate/higher saturated fat diet. Although the basal diet
was associated with only moderate reduction in LDL cholesterol in the
pre-weight loss phase, individuals on this diet actually achieved
significant reduction of LDL cholesterol in the post-weight loss
phase. The weight loss had virtually no effect on the LDL levels
for individuals on the other diets.
Dr. Krauss noted that the published studies he reviewed would have
predicted an insignificant reduction of LDL on the lower saturated fat
diet, yet this study found a substantial reduction. There
appears to be some interaction between carbohydrate intake and the
magnitude of saturated and unsaturated fatty acids on LDL cholesterol.
Dr. Krauss offered a potential explanation for these findings.
Studies conducted in his and others labs indicate that carbohydrate
intake and weight both affect metabolic pathways that give rise to
different forms of LDL. Under conditions where triglyceride
levels are low, such as in lean or active individuals or those with
low carbohydrate intake, the particular pathway that comes from the
liver results in a form of large or medium-sized LDL particles that
are cleared effectively by the LDL receptor. When triglyceride
levels are higher due to higher carbohydrate intake, increased
adiposity, or sedentary lifestyle, the pathway shifts to allow the
liver to deliver more triglycerides. This gives rise to a
distinct, small LDL particle that is cleared less avidly by LDL
receptors.
This latter pathway is a critical element of the metabolic
syndrome, type 2 diabetes and obesity. Low HDL, insulin
resistance, and many other metabolic disturbances that increase the
risk for heart disease accompany the small LDL response. The
low-carbohydrate, high-fat diet was associated with a substantial
reduction in small LDL when compared with the control diet,
independent of the saturated fat content of the diet. This is a
major benefit of weight loss and needs to be considered in the overall
equation.
Dr. Krauss noted that the triglyceride change associated with
low-carbohydrate, high-fat intakes appears to be a more significant
determinant of the small LDL response than saturated or unsaturated
fat content. However, saturated fat increases the concentrations
of the larger LDL particles, which are more cholesterol enriched.
Dr. Krauss stated that the best way to integrate this biochemistry
is to look at the ratio of total to HDL cholesterol. Both of the
low-carbohydrate, higher-protein, higher-fat diets in this study led
to a reduction in this ratio that was significantly different from the
control diet and more than would be predicted from previous studies.
However, the incremental benefits of weight loss on the atherogenic
indices are much less pronounced at low carbohydrate to fat ratios.
Dr. Krauss noted that there are no significant differences when
combining the effects of diet and weight loss. This suggests
that the carbohydrate to fat ratio and adiposity contribute to the
same net pathways.
Dr. Krauss noted that the experimental diets in this study used a
higher protein intake to allow lower carbohydrate levels. The
possible effects of increased protein intake are relatively under
studied.
Dr. Krauss concluded his presentation by addressing the
relationship of carbohydrate and fat intake to weight maintenance and
weight loss. He reviewed studies of at least one year in
duration that related change in percent fat intake to loss of body
weight, with fat intake ranging from about 12 percent to about 32
percent. As Dr. Hu mentioned earlier, these studies suggest that
lower-fat diets do not seem to offer particular advantages for weight
loss, although they may be acceptable for weight maintenance.
Ultimately, it is total energy and total calories that matter. It is
clear from all the data that the macronutrient distribution is not a
factor influencing weight loss when calories are controlled.
Two studies conducted in the past year sought to provide patients
with dietary recommendations based on literature from the Atkins
program versus conventional dietary recommendations. These
studies involved diets that were very low in carbohydrate and higher
in fat and protein (following the recommendations of the Atkins
program) compared with lower fat diets (following the conventional
dietary recommendations). Data from these studies showed that a
low-carbohydrate diet performed better than the low-fat diet over a
six- month period. However, a third study the only one carried
out for a period longer than six months found that these two diets
converged over time, presumably due to lack of compliance. The
lipid and lipoprotein changes in the last study are similar to those
found in the study conducted by Dr. Krauss. With lower
carbohydrate intake, the influence of fat content composition on
insulin sensitivity appears to be blunted.
In conclusion, Dr. Krauss stated that reduction in total fat leads
to modest reductions in weight. Reduction in dietary
carbohydrate to less than 30 percent of calories leads to large early
reductions in body weight. In both cases, reductions in body
weight are clearly related to changes in energy intake. However,
these changes may not be sustainable for most individuals.
Trials of low-carbohydrate diets for long-term prevention of weight
gain are lacking.
Dr. Joanne Slavin, University of Minnesota,
discussed dietary approaches to weight control, with an emphasis on
the role of carbohydrates and fiber. She noted that the primary
mechanism of weight control is to eat fewer calories and exercise
more.
Eating less carbohydrate can lead to significant change, because
carbohydrates are the major source of calories. Eating less fat
has a positive impact on calorie density, but palatability can be an
issue. Eating more protein will also lead to lower calorie
intake. But, Dr. Slavin stressed that there is little data that
any of these strategies are very effective in the long run.
The eating and exercise targets from the IOM Report propose 45 to
65 percent of calories from carbohydrates, 20 to 35 percent of
calories from fat, and 10 to 35 percent of calories from protein,
combined with a total of at least one hour each day in moderately
intense physical activity, which is double the daily goal set by the
1996 Surgeon General's report. Dr. Slavin stressed that
nutritional advice is wasted without physical activity. She
expressed concern that consumers do not understand the concept of
energy balance.
Dr. Slavin reported that case-control studies of dietary
composition find a pattern of Low- carbohydrate intake in obese
subjects. These studies also found a positive association
between the percentage of dietary fat and Body Mass Index (BMI).
Dr. Slavin noted that the form of carbohydrate is important, but there
is a shortage of good data in this area.
Studies have found that low-fat diets are the optimal choice for
the prevention of weight gain and obesity. Low-carbohydrate
diets are more effective at 3 and 6 months for weight loss, but there
is no difference between the two types of diets at 12 months.
Overweight subjects who consume low-fat, high-carbohydrate diets tend
to eat fewer calories, lose weight, and lose body fat.
Dr. Slavin noted that the National Weight Control Registry is a
useful source of information on weight management because it tracks
people who have lost at least 30 pounds and maintained that loss for
at least one year. On average, the individuals in the Registry
get 24 percent of their calories from fat, 56 percent from
carbohydrate, and 19 percent from protein. Many people stated
that eating breakfast was an important factor in their weight loss.
Most reported that they regularly monitor their food intake and body
weight. All reported high levels of physical activity.
This information underscores the fact that weight control is a
lifelong process that does not end when the desired weight is
achieved.
Dr. Slavin noted that nutritionists typically look at things that
can be measured, whether it is calories, macronutrients, or
micronutrients. She suggests that broader things such as
dietary patterns, intake of whole foods, timing and frequency of meals
are actually more important than we have given them credit for.
Another problem in nutrition is that elements of the diet are
interdependent. Only in a controlled feeding study is it
possible to hold fat intake constant and vary fiber intake. In the
real world, changing one aspect of the diet can result in many other
associated changes in nutrition. Reducing the amount of fat in
the diet will affect the intake of fat-soluble vitamins, while
eliminating high-carbohydrate foods can affect intake of other
nutrients.
In determining the appropriate balance of macronutrients for an
individual, Dr. Slavin sets the base with proteins. The DRI
recommends a range of 10 to 35 percent of calories from protein, 20 to
35 percent of calories from fat, and 45 to 65 percent of calories from
carbohydrates. There needs to be enough fat to get essential
fatty acids, fat-soluble vitamins, minerals, and other fat-soluble
phytochemicals that are just starting to be studied.
Carbohydrates are also an important source of vitamins, minerals,
and phytochemicals. The carbohydrate allowance also needs to
include adequate dietary fiber, which is 25 to 38 grams per day,
depending on age. The individual's calorie budget and activity
level are important factors in determining the overall macronutrient
balance.
Dr. Slavin emphasized that the various types of carbohydrates are
not equal. They differ in terms of their chemical structure
(mono-, di-, and polysaccharides). They differ in terms of
digestibility starches and sugars get digested, but fiber does not.
They differ in terms of speed of digestion and absorption. She
noted that this variable, often quantified as glycemic index, is
important for diabetics. Carbohydrates differ in terms of
fermentability some fibers are more likely than others to ferment in
the large intestine, and some ferment more quickly. Finally, the
physical structure of carbohydrates including particle size is
important, though it is hard to measure.
Dr. Slavin stated that there is general agreement that whole grains
contain many valuable components. However, many of these
important nutrients are lost in the milling that is required to
produce the refined grain products that many consumers prefer because
of their taste, texture, and longer shelf life.
Dr. Slavin illustrated the evolution of dietary advice regarding
whole grains over the past two decades. Prior to 1980, whole
grains were promoted as a source of fiber. In 1989, the National
Academy of Sciences report, Diet and Health, linked whole
grains with reduced risk for heart disease and some cancers. In
1999, the FDA permitted whole grain health claims on food packaging.
The fifth edition of the Dietary Guidelines, issued in 2000,
emphasized whole grains. Increased whole grain consumption is
one of the objectives of Healthy People 2010.
The 2000 Dietary Guidelines recommended "several servings"
of whole grains but did not set a quantitative goal. The
Healthy People 2010 objectives aim for three servings per day, a
goal that is also promoted by the USDA and the American Dietetic
Association. However, a 1995 study found that fewer than 10
percent of Americans were only eating one serving a day of whole
grains. A study published last year found that the average whole
grain intake was 0.8 servings a day for pre-school children and one
serving for adolescents.
Dr. Slavin stressed that before the Committee considers increasing
the goal, it is important to consider why people are not meeting the
current recommendations. USDA data show that whole grains
represent only 15 percent of U.S. grain consumption and 85 percent of
grains consumed is non-whole grain. If only whole grains are
recommended, consumers who are currently consuming 85 percent
non-whole grains will need to find acceptable ways to replace 85
percent of the grains in their diet. USDA data also show that
consumers get whole grains from many different products, including
breads, breakfast cereal, and grain snacks. The food industry
will need to come up with more choices within those categories for
consumers to meet whole grain recommendations.
Dr. Slavin summarized a review of whole grains and human health
that is currently in press. This review provides strong evidence
that whole grains are protective against cardiovascular disease,
cancer, diabetes, obesity, and all-cause mortality.
Epidemiological studies suggest that an intake of three servings of
whole grains per day is associated with significant risk reduction of
type 2 diabetes. Another recent study found that whole grain
consumption was significantly associated with insulin sensitivity.
A clinical study in which overweight subjects were fed whole and
refined grain diets for six weeks found that fasting insulin was 10
percent lower and insulin sensitivity improved with the whole grain
diet. Subjects on the whole grain diet also tended to lose
weight.
Dr. Slavin reviewed epidemiological studies relating to whole
grains and obesity. In the Framingham offspring study, whole
grain intake was inversely associated with BMI. In the Nurses'
Health Study published in 2003, women who consumed more whole grains
consistently weighed less than women who consumed less whole grains
and also had a significantly lower risk of major weight gain.
Another study found that whole grain foods improve markers of bowel
health in overweight men.
Although Dr. Slavin does work in the field of dietary fiber, her
laboratory also works with lignans and
phytoestrogens that are associated with dietary fiber in plant foods.
High levels of serum enterolactone, a mammalian lignan, have been
associated with decreased cardiovascular disease. People who eat
more whole grains have higher levels of serum enterolactone.
Other valuable components in whole grains that are known to have
protective effects against chronic diseases include sterols, resistant
starch, antioxidants, and phytate.
Dr. Slavin stressed that it is important to help consumers
understand what whole grains are and where they can be found.
The best way to find whole grain products is to read the ingredients
label. A whole grains seal or a whole grain health claim on the
package can be helpful, but different companies use them in different
ways. Many products that appear to be whole grain foods such
as multi-grain bread are not. Processed foods, such as cereal
and crackers, can be whole grains.
She stated that whole grains typically are our best source of
dietary fiber. The IOM recommends 25 grams per day for women and
38 grams per day for men under 50, and 21 grams per day for women and
30 grams per day for men over 50. These recommendations are
based on protection from cardiovascular disease. There is
insufficient evidence to set an upper intake level for fiber.
Current fiber intake is only 12 to 15 grams per day, so most people
get less than half of what they need.
Dr. Slavin pointed out that fiber is not a nutrient in the usual
sense. Dietary fiber consists of non-digestible carbohydrates
and lignan that are intrinsic and intact in plants. Functional
fiber consists of isolated, non-digestible carbohydrates that have
beneficial physiological effects in humans. Total fiber is the
combination of dietary and functional fiber.
Dr. Slavin emphasized that fiber that is intact and naturally
occurring in food is preferable to isolated fiber, which is the form
found in supplements. The original hypothesis regarding the
benefits of dietary fiber was based on populations consuming unrefined
diets that were high in dietary fiber and slowly digested
carbohydrates. Fiber-rich foods contain many biologically active
compounds that are integrated into the plant cellular structure.
These compounds are handled differently in the body than isolated
fiber.
Dr. Slavin was pleased that Dr. Hu had mentioned the benefits of
cereal fiber. She referenced a recent study that looked at cereal,
fruit, and vegetable fiber intake and the risk of cardiovascular
disease in elderly individuals. This study found that, even late
in life, cereal fiber consumption is associated with lower risk of
cardiovascular disease.
With regard to fiber and weight loss, Dr. Slavin noted that fiber
has many effects on the digestive tract. It takes longer to
digest, it slows down absorption, it slows down stomach emptying, and
there is more loss of fecal fat. Studies that compared the
effects of high-fiber versus low-fiber diets found about a 10 percent
decrease in voluntary energy intake. People tend to eat less on
high-fiber diets. These effects were more pronounced in obese
subjects. There is some data that fiber supplements taken
post-weight loss aid in weight maintenance.
A recent study published in The Journal of Nutrition
compared the effects of fermentable and non-fermentable fiber
supplements (27 grams per day). The researchers saw no effect on
food intake or body weight. This pilot study does not support
the use of fiber supplements for weight loss. However, Dr.
Slavin noted that this was only a three-week study.
Dr. Slavin shifted the focus to the issue of fiber and satiety.
She presented a recent study that measured glycemic response and
satiety response in subjects who ate several types of breads.
While there was very little difference in the glycemic index for the
various types of breads, there were fairly significant differences in
satiety that were not totally related to fiber. Of the breads
that were tested, the low-fat, high moisture bread had the biggest
change in the feeling of fullness. This suggests that although
fiber is one element of satiety, the volume of the food affects how
full people feel. Another study on satiety found that a more
viscous beverage produced greater and more prolonged reductions of
hunger. These studies underscore that how foods look and taste
is as important as their nutritional value.
Dr. Slavin noted that there are fairly consistent findings that
higher fiber intakes tend to be linked with lower body mass indexes.
The Seven Country Study found that physical activity and dietary
fiber, but not dietary fat, were related to skin-fold thickness.
Another study, the Coronary Artery Disease Risk Development in Young
Adults (CARDIA) study, found that fiber intake predicted weight gain
in young adults. Dr. Slavin expressed concern that
low-carbohydrate diets are also low-fiber diets. Data published
in 2000 found that the Atkins diet provided only 4 grams of fiber per
day, the Zone diet provided 18 grams per day, while the plant-based
Pritikin and Ornish diets provided 40 and 49 grams, respectively.
Dr. Slavin turned to a discussion of eating patterns. A
recent study found that children who eat breakfast cereal had a low
BMI. Another study found that intake of whole grain breakfast
cereals was inversely associated with total mortality. Data from
the National Weight Control Registry also suggested that eating
breakfast is important. Dr. Slavin stressed that it will be
important to emphasize to consumers that when you eat is as important
as what you eat.
Dr. Slavin noted that most Americans are meeting less than 70
percent of the DRI for fiber. On average, men need an additional
20 grams per day, and women need an additional 12 grams per day.
Those on a low-carbohydrate diet have an even greater deficit.
Dr. Slavin stressed that the Committee needs to consider how it will
help consumers get the fiber they need. Assuming an average of 3
grams of fiber per serving, men would need 12 servings of a
fiber-containing food per day, and women would need 8 servings.
Another option would be to increase the fiber content of popular foods
such as high-fiber cereals, or increase consumption of legumes, dried
fruits, fortified foods, or supplements.
Dr. Slavin concluded her presentation with several recommendations
for the Committee. First and foremost, she emphasized that
people eat food, not nutrients. The guidelines need to include
foods that people like and also provide essential nutrients.
Taste, convenience, and familiarity are important.
Second, she noted that whole grains are an important
vehicle for dietary fiber and other nutrients. The
change would be significant if we can get Americans to
increase their consumption of this valuable food group.
Finally, she recommended that strategies are
needed to get nutrients, including fiber, into the
low-calorie diets that are required for typically inactive
Americans, and energy levels must be appropriate for
sedentary individuals. The base of the Food Guide
Pyramid should stress the importance of fruits, vegetables,
grains, and legumes.
Discussion
Dr. King thanked the panelists for their presentations and opened
the floor for discussion.
Dr. Nicklas directed her question to Dr. Krauss and Dr.
Hu. She referenced the literature showing that less
than five percent of dietary ALA is available for conversion
to EPA and DHA, which is controversial. She noted that
Dr. Krauss very nicely showed that ALA decreases
triglycerides. She asked if there was any evidence
with regard to outcomes for cardiovascular disease between
the different types of omega-3.
Dr. Krauss replied that it is well established that the
longer chain omega-3s are potent triglyceride lowering
agents. On a gram-for-gram basis, he was not sure how
different they are from ALA. The dose that is
typically used to show triglyceride lowering is far higher
than we could expect to achieve in the diet. He
deferred to Dr. Hu with regard to the disease outcomes.
Dr. Hu agreed with Dr. Krauss that there is no question
that fish oils substantially lower triglycerides.
There have been many studies examining the effects of ALA
and canola or soybean oil on triglycerides, but the results
are not consistent.
The data for fish oil omega-3 is more convincing. Three
or four randomized clinical trials including the Diet and
Reinfarction Trial (DART) Study, the GISSI Prevention Trial,
and DART-2 have looked at heart disease and fish oil.
The GISSI Trial and DART have shown conclusively that
increasing fish intake can lower coronary heart disease
(CHD) mortality rate. Fish oil is probably beneficial
in reducing sudden deaths and fatal CHD among people with
established heart disease. There have been no trials
to determine whether fish oil can reduce heart disease in
the general population.
No randomized trials have been conducted for ALA and CHD
in either the general population or the high-risk
population. Dr. Hu mentioned the Lyon Diet Heart
Study, which showed that a diet high in ALA and with a high
amount of fruits and vegetables substantially reduced the
risk of sudden deaths, total mortality, and even cancer
mortality.
Dr. Kris-Etherton asked Dr. Hu if he would distinguish
between the longer chain omega-3s and ALA in his
recommendations that nutritional strategies should maximize
the benefits of both n-6 and n-3 fatty acids.
Dr. Hu replied that ALA is an essential fatty acid, while
fish oil, per se, is not. If you have adequate ALA,
you don't need fish oil. The amount of ALA in the diet
is at least 10 to 20 times higher than fish oil. Dr. Hu agreed that it is probably important to have separate
recommendations for ALA and fish oil.
Dr. Pi-Sunyer asked Dr. Krauss whether, given the fact
that monounsaturates drive the change in total HDL
cholesterol, the Committee should recommend increasing
monounsaturated fat.
Dr. Krauss replied that he would not necessarily distinguish mono-
and polyunsaturates with respect to their impact on risk for heart
disease. In terms of the data, most of the effect is due to
monounsaturates because they are a larger percentage of the variation
in fat intake that has been studied.
Dr. Lupton asked whether there is sufficient evidence to
make specific recommendations on glycemic versus
non-glycemic carbohydrates. Dr. Slavin stated that the
glycemic index is an interesting concept, but it is not
useful as a general guideline. Dr. Krauss noted that
the glycemic index poses three problems: it is difficult to
quantify and define complex carbohydrates; glucose is not
the only issue with carbohydrates; and it is not clear
whether there is any benefit regarding satiety and other
issues with weight loss. Dr. Hu noted that the
glycemic index has been misused to classify specific foods
as "good" or "bad" and should not be used as the sole
criteria for choosing foods. However, it could be a
useful research tool and could serve as the basis of
recommendations that address eating patterns, such as
guidelines to reduce the overall glycemic index of the diet.
This may be more useful for diabetics than for general
audiences.
Dr. Pi-Sunyer noted that it is important to consider the
overall glycemic index of a mixed meal. For example,
whole grains lower the glycemic index of bananas.
Returning to the issue of dietary pattern and cancer
risk, Dr. Go asked the panel whether it is the type of fat
or total fat intake that is important. Dr. Hu
responded that there is no relation between total fat intake
and cancer risk. The evidence is fairly strong that
higher levels of animal fat result in greater risk for colon
cancer, but it is not clear whether that is due to the fat
or other compounds in meat. There is no such
correlation with breast cancer. The link between fiber
and cancer risk is still undetermined. Dr. Slavin
noted that colon studies are fairly clear that higher fiber
intake is protective for colon and breast cancer, although
these findings overlap with phytoestrogen data. It
will be important to find dietary patterns that are
protective.
Dr. King asked whether the DRIs for fiber are reasonable
if no one can follow them. Dr. Slavin responded that
the recommendations are not impossible on a plant-based
diet, though she acknowledged that they are difficult to
meet with the typical diet in this country. The DRIs
may be too high for children, but they are a good goal for
adults. The real cause for concern is diets that have
no fiber.
Dr. Nicklas noted that most studies on fiber and satiety
have focused on adults. She asked how the lack of
fiber affects satiety and intake of other foods in children.
Dr. Slavin responded that a child's initial diet breast
milk contains no fiber. There is a gradual
transition in the diet to foods that contain fiber. In
Dr. Slavin's opinion, the DRI levels for fiber in children
are too high.
Dr. Lupton asked whether types or amounts of
carbohydrates should be the driving force behind
recommendations and whether there should be a recommendation
on dietary fiber. Dr. Slavin reiterated her concern
that recommendations on dietary fiber lead to the use of
supplements rather than real foods, with a corresponding
loss of other nutrients in plant-based foods. Dr. Hu
stated that for maximum benefits, whole grains should be the
driving force behind carbohydrate recommendations. It
is important to stress that refined carbohydrates should be
reduced to balance the increased intake of whole grains.
He noted that it is difficult for the general public to
count grams of fiber. Dr. Slavin stated that she had
been surprised to find that there was no link in the
scientific data between carbohydrate intake and obesity.
Dr. Hu noted that it is very difficult to study the relation
between carbohydrates and body weight because the metabolic
process is complex.
Dr. Kris-Etherton asked if the speakers could recommend a
fat to carbohydrate ratio for weight loss and maintenance.
Dr. Krauss did not think that any macronutrient ratio is
better for weight loss, though a low-fat diet appears to be
better for maintenance. He noted that the distribution
between fats and carbohydrates and the types of
carbohydrates in the diet become minimal as physical
activity increases. It would be important to promote a
variety of ways to achieve weight loss. While the
level of carbohydrate consumption in this country may be
excessive, reduced carbohydrate intake needs to be balanced
with the need for fiber.
Dr. Slavin stated that there is no real solution without
exercise. High carbohydrate diets are useful for
higher activity levels. There need to be better
choices within that category.
Dr. Hu agreed that there is no definitive answer or
optimal diet because activity levels and metabolic profiles
vary. It is important to balance science with what
people will do. The Atkins and Ornish diets represent
two extremes; few people can stick with them. Although
weight loss studies are inconclusive, they seem to suggest
holding fat constant and increasing protein versus
carbohydrate, for levels of about 25 percent protein, 35
percent fat, and 40 to 45 percent carbohydrate.
Studies are needed in this area.
Dr. Pate noted that the current Dietary Guidelines
say to aim for total fat intake of no more than 30 percent
of calories as fat. He asked if the panelists would
recommend changing that. Dr. Hu said yes; Dr. Slavin said
no, except for extremely active individuals.
Dr. Clydesdale asked if it would help to change food
labeling to reflect fiber content. Dr. Slavin said
this would be helpful, because consumers do want to do
better.
Dr. Appel asked whether the Committee should make a
distinction between types of carbohydrates, given the
confusion regarding this issue. Dr. Hu stated that
there is strong evidence for the benefits of substituting
whole grains for refined grains. Dr. Krauss said the
distinction should be made, but it could be hard to
translate this into recommendations that are actionable.
He suggested focusing on sugars and fiber. Dr. Slavin
stated that the Committee should make no such distinction
because there is little evidence that carbohydrates are bad.
The current information of total carbohydrates on the
Nutrition Facts Label, with the sub-listing of dietary fiber
and sugars should be retained. She recommended
including a fiber guideline due to its protective factors
against chronic disease.
(Lunch: 12:40-1:45)
Dr. Janet C. King
welcomed Committee members back to the meeting and introduced Dr. Mary
Ann Johnson, who was invited to speak on nutritional needs of the
elderly. Dr. Johnson is a Professor of Foods and Nutrition at
the University of Georgia. Her interests and areas of expertise
include nutrient bioavailability and interactions involving vitamins
and minerals. Dr. Johnson's research targets human populations,
particularly older individuals. She has studied older
individuals in personal care homes, those who are receiving home
delivered meals or meals at congregate feeding centers,
community-dwelling elderly, as well as the elderly in general.
Dr. Johnson works with state and local agencies through the Georgia
Division of Aging Services.
Presentation and Discussion: Nutritional Needs of the Elderly M.
Johnson
Dr. Mary Ann Johnson, University of Georgia,
began her presentation by providing some context for the issues she
was asked to address. Currently, 35 million people in the U.S. are
over age 65 (more than 12 percent of the population). By 2020,
there will be about 54 million older adults. By 2050, there will be 70
million older adults in the country one out of every five people.
Older adults vary tremendously in their functional level. While
some are training for competitive athletic events, others at the same
age are institutionalized with nutrition related disorders, such as
diabetes or heart disease, or other disorders, such as dementia.
Dr. Johnson pointed out that while dietary
recommendations are generally developed with
community-dwelling, healthy individuals in mind, many
federal and state regulations mandate that these and other
diet-related guidelines be used for meal planning for
congregate and home delivered meals and for meals at
long-term care and assisted living facilities and geriatric
hospitals.
Dr. Johnson stated that many older people have a
tremendous stake in what the Committee deems as a healthy
diet because they are at high risk for nutrition-related
chronic diseases. She questioned the endpoints for
determining nutritional adequacy, noting that poor vitamin
or mineral status have not been ruled out as risk factors
for age-related disorders that greatly impair the quality of
life for many older people, including sarcopenia, impaired
muscle strength, falls, dementia, delirium, depression,
hearing and visual disorders, and impaired immune function.
Dr. Johnson presented a table summarizing how and why
certain nutritional requirements change with age and how
these changes are related to food intake:
- Energy: Energy needs decrease with age
because older adults have less muscle tissue and hence less
energy expenditure. As a result, they need to eat less to
maintain weight.
- Iron: Iron needs in women over age 50 decrease by
more than 50 percent due to cessation of menstruation. In theory,
women over age 50 could eat less iron-dense foods.
- Vitamin B-6: Requirements for this nutrient increase
with age. Several studies have shown a relationship between oral
intake of vitamin B-6 and certain biochemical processes. There
are many sources for this nutrient, including typical foods, fortified
foods, and supplements.
- Vitamin B-12: This nutrient, along with calcium and
vitamin D, is widely recognized as a nutrition and health problem in
older people. The RDA specifies that above age 50, the majority of
vitamin B-12 should be from a crystalline form. This is due to
impaired absorption that seems to be linked to the helicobacter pylori
(H. Pylori) microorganism. Vitamin B-12 can be obtained
in some fortified foods and through supplements. Federal
regulations do not require adding vitamin B-12 to fortified foods, and
it is not naturally present in whole grains.
- Calcium: The need for calcium increases with age to
promote bone health in both men and women. The change appears to
be related to a decrease in absorption. Calcium is present in typical
foods, especially in dairy products. The recommendations are two
to three servings of dairy foods for adults and older people, but the
typical intake of milk is only about one serving. The current
Dietary Guidelines emphasize that people who consume few dairy
foods should take a calcium supplement. Dr. Johnson encouraged the
Committee to retain that language.
- Vitamin D: There is a three-fold increase in the need
for this nutrient among older adults. The current recommendation
is five micrograms a day for adults under age 50, 10 micrograms from
age 50 to 70, and 15 micrograms for those over age 70. This
increasing need appears to be linked with decreasing ability of the
skin to synthesize vitamin D from the sun. The most common
source of vitamin D is fortified milk, because few typical foods
contain this nutrient. However, it would take six cups of milk
per day to meet the vitamin D recommendation for those over age 70.
Also, most other dairy foods are not made with vitamin D-fortified
milk. Dr. Johnson encouraged the committee to keep the current
recommendation, but to add that older adults may need a supplement of
vitamin D.
- Vitamin E: There is some evidence that high intake
might prevent some age-related disorders, though the issue is
controversial and the evidence inconsistent. There is currently
no change in the RDA for older adults. Vitamin E is low in
typical foods and it is difficult to design a diet that meets the
current RDA. Vitamin E is present in many supplements.
There are many chemical forms of vitamin E in foods; the chemical
forms in supplements would be much more limited.
Dr. Johnson noted that she was less enthusiastic about plant-based
diets than previous speakers because even the most well designed
plant-based diets are deficient in some nutrients, particularly
vitamins D and B-12 which are not naturally present in plant-based
diets.
Dr. Johnson stated that, in her opinion, indexing beyond age and
gender would be extremely impractical for the general public. It
would be especially difficult for those using the Dietary
Guidelines for meal planning in long-term care facilities,
assisted living, home delivered, and congregate meals. Fiber
would be one exception, as discussed earlier in the day, but
micronutrient requirements need to be independent of energy.
Dr. Johnson stated that nutrition problems in older people are not
related to energy density problems. They have more to do with
problems in food choices, nutrition knowledge, availability of healthy
food, and access to food. Food security is also an issue for
older adults, many of whom have to choose between buying food and
buying medicine or paying rent or utilities. A recent study
suggests that the issue of food security is different among older
people because they are more knowledgeable about what foods are
healthy.
Dr. Johnson stated that while the nutritional problems of the
elderly could be overcome in part by consuming more nutrient-dense
diets, the requirements for some nutrients are so high that they are
beyond what typical, or even fortified foods, can provide. It
would be difficult to redesign the food supply to meet nutrient
requirements across the lifecycle when younger adults need five
micrograms of vitamin D a day and older people may need 15 or more.
Dr. Johnson then presented new evidence that illustrate potential
health benefits of vitamin B-12, vitamin D, and vitamin E. She
stressed that it is important to include a message about vitamin B-12
and vitamin D in the
Dietary Guidelines and that the Committee should consider the
potential benefits of vitamin E.
Vitamin B-12 status has been linked to depression in some studies,
though not all. Depression is a widespread disorder in older people,
and it has also been linked to other nutrients. Poor B-12 status has
been linked in some studies to poor cognition, dementia, and
neurophysiological disorders, which are also common problems in older
people. In Dr. Johnson's opinion, the 1998 RDA for B-12 may be
too low. Since the DRIs were published for the B vitamins, at
least four studies have suggested that older people may need nearly
three times the recommended amount of the crystalline B-12.
Given the importance of B-12, Dr. Johnson stressed that it is vital to
ensure that people get at least what is currently officially
recommended. Crystalline intake should be tracked at the
national level and included in the USDA databases.
Vitamin D is another important nutrient for older people. In
addition to the role of vitamin D in bone health, there is an emerging
literature showing that poor vitamin D status is linked to falls.
Other studies are examining the role of vitamin D in muscle function,
the link between vitamin D deficiency and chronic pain, and the link
between low vitamin D status and multiple sclerosis. Several
researchers are concerned that the 1997 adequate intake for vitamin D
may be too low because the level that is associated with optimal
health is not well defined. While this issue is being clarified,
it is important to ensure that older people are getting the vitamin D
that they need. Dr. Johnson encouraged the Committee to keep the
recommendation that older people may need a vitamin D supplement.
It will be difficult to fortify the food supply to ensure adequacy
across all age groups.
Vitamin E is controversial but quite interesting. Poor
vitamin E status has been linked in some studies to cardiovascular
disease and dementia and other cognitive disorders. Some studies
have shown that vitamin E supplements may offer some benefit for
various cardiovascular disease outcomes, dementia and cognitive
disorders, and immune function. Dr. Johnson urged the Committee
to consider how the potential benefits of high doses of vitamin E
might be included in nutritional recommendations for older people.
In conclusion, Dr. Johnson noted that older people can make
beneficial changes in their nutrition and physical activity patterns.
Well-designed, community-based educational programs can help them make
these changes. She emphasized that older people need practical,
reliable, and scientifically valid advice about healthy eating to
ensure nutritional adequacy, decrease their risk of chronic disease,
and improve their quality of life.
Discussion
Dr. King thanked Dr. Johnson for her comprehensive overview of the
nutritional needs of the elderly. She asked if she was correct
in understanding that Dr. Johnson suggested that the Committee
recommend supplements of vitamin D, calcium (if they don't consume
dairy products), and supplements of vitamin E. Dr. Johnson
stated that she would encourage the Committee to retain the language
in the 2000 Dietary Guidelines for vitamin D and calcium.
The question of vitamin E supplementation requires further review.
Dr. Weaver stressed that vitamin D requires more
attention. She hoped the NIH conference on vitamin D
held last October would help raise awareness that the vitamin
D requirements may be too low. In the meantime, UV-B
lights may be the most practical approach. Dr. Johnson
noted that UV-B light exposure can raise the risk of skin
cancer and that UV-B light exposure is not that well
quantified for older people.
Dr. Weaver asked if Dr. Johnson was recommending
crystalline form of vitamin B-12 and how she would handle the
recommendations. Dr. Johnson responded that the RDA for
B-12 says that the majority should come from crystalline,
whether through supplements or fortified foods. The
problem is that few fortified foods contain B-12 besides
fortified breakfast cereals. Dr. Johnson noted that
vitamin B-12 is very common in multi-vitamins.
Referring to Dr. Johnson's statement suggesting that the
dietary recommendations for older people should not be
indexed for energy, Dr. Pate asked if she would argue against
making adjustments for physical activity level. He also
asked if her reasoning was based on potential complications
for institutions that are required to follow the Dietary
Guidelines, or if it was based on other factors.
Dr. Johnson clarified that she was speaking mainly of the
micronutrients, not fat and fiber. There is no good
reason to index most micronutrients to energy. However, Dr.
Johnson agreed that physical activity is as important for
older people as for people of any other age.
Dr. Clydesdale asked what treatments exist for vitamin
B-12 deficiency. Dr. Johnson stated that B-12
deficiency in older people results from a variety of factors,
one of which is the loss of the intrinsic factor, which is a
protein that binds to B-12 to deliver it effectively to the
intestinal tract. This results in a much more profound
inability to absorb B-12 over time. Oral intakes of at
least 500 micrograms per day appear to overcome the loss of
instrinsic factor as well as restore B-12 stores resulting
from other causes of B-12 deficiency (e.g., atrophic
gastritis). The more common cause of B-12 deficiency is
atrophic gastritis, which involves a decrease in the
production of acid and pepsinogen in the stomach and
subsequent decrease in cleavage of B-12 from animal foods.
It is currently believed that atrophic gastritis does not
markedly diminish the ability to absorb crystalline B-12
found in some dietary supplements and fortified foods, which
is why crystalline B-12 is recommended for adults over age 50
as a preventive measure.
Dr. Nicklas asked if some macronutrients were more
difficult to digest than others with increased aging.
Dr. Johnson replied that most research suggests that general
processes of absorption are not that different with older
people. Changes with absorption are usually thought to
be disease related.
Dr. King asked if Dr. Johnson would recommend any changes
in the food patterns for elderly individuals in comparison to
younger adults, since her comment about plant-based diets
seemed to imply that older adults might need higher levels of
animal protein. Dr. Johnson noted that the key issue is
to identify strategies to get older people to follow the
existing recommendations, rather than developing new food
patterns. She clarified that she did not mean to imply
that one type of protein was better for older people.
Her point was that a plant-based diet does not provide
vitamin D and vitamin B-12. Supplements are the best
way for older people to get some nutrients unless we
radically change our food fortification practices.
Dr. Kris-Etherton asked whether Dr. Johnson would
recommend that supplements be at a level to achieve a DRI
recommendation, or if there would be any reason to go higher,
such as with vitamin E. Dr. Johnson said that it is
premature to make specific recommendations for vitamin E at
this time.
Dr. Weaver noted that Dr. Johnson had not recommended any
specific differences in fiber intake for the elderly and
asked her to comment on whether age would make any difference
in our understanding of the relationship between alcohol
intake and chronic disease. Dr. Johnson stated that the
current fiber recommendations are based on studies that
include many older people. She would recommend the
current DRIs.
Dr. Johnson referred the question of alcohol and age to
the Committee because she was not familiar with the
literature. However, she noted that since older people
consume fewer calories, they need to be mindful of the fact
that alcohol does not provide micronutrients. In
addition, alcohol-induced impairments such as falling and
visual and cognitive problems could be exaggerated in older
people.
Dr. King referred to Dr. Johnson's statement that the
capacity to absorb calcium diminishes with aging and noted
that some literature suggests the same is true for iron and
possibly zinc. She asked whether the capacity of older
adults to absorb these minerals would be impaired if the
fiber recommendation for the elderly was the same as for
younger adults. Dr. Johnson stated that the impact of
fiber on mineral absorption is not significant. Dr.
King noted that the phytate that is found in the fiber is
usually the problem. Dr. Johnson agreed that could be
an issue if consumption of unleavened whole grains increased,
but, in general, fiber is not a cause for concern.
Dr. King thanked Dr. Johnson for her presentation.
(Break: 2:30-2:45)
Public Oral Testimony
Dr. King introduced the public oral testimony section of the
meeting. She noted that over thirty individuals and groups would
be sharing their research perspectives and expertise with the
Committee. She reiterated Dr. Beato's statement regarding the
important role of public comments in developing the Dietary
Guidelines and emphasized that the Committee would welcome written
comments throughout the process. After summarizing the
procedures for submitting written comments that were outlined in the
Federal Register notice, she laid out the ground rules for the
public oral testimony. She noted that presenters would have
three minutes to present their testimony and should stop speaking when
the red light came on at the podium. She then introduced the
first presenter.
Mr. Richard Hanneman, Salt Institute, stated that his
organization is the trade association of salt companies and is funded
from membership dues. He acknowledged that salt in the diet is
related to blood pressure and that federal policy since 1980 has
encouraged a reduction in dietary sodium intakes. He called the
Committee's attention to three important developments in the past
decade: the emerging consensus that evidenced-based medicine should
direct policy; the emerging consensus that evidence-based medicine
should focus on health outcomes; and the Data Quality Act, which
requires that data, used as the basis for recommendations, should be
replicable, and should meet certain quality standards.
Mr. Hanneman noted that the recommendations of the HHS Preventive
Services Task Force, the Cochrane Collaboration cited by Dr. Hu, and
the Canadian guidelines have all concluded that there is insufficient
evidence to support the reduction of dietary sodium. He stated
that the Committee should focus its efforts on improving overall diet
quality. The Salt Institute endorses the Dietary Approaches to
Stop Hypertension (DASH) Diet, which is also endorsed by the
Seventh Report of the Joint National Committee on Prevention,
Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7).
The DASH-Sodium study shows that sodium reduction is ineffective for
normotensives and not very important for hypertensives.
The Salt Institute also is concerned about the declining amount of
iodine in the American diet a nutrient that is provided through
iodized salt.
The Salt Institute recommends that the Committee make
evidence-based recommendations ensuring compliance with the Data
Quality Act and eliminate the dietary guideline on salt.
Mr. Robert Earl, National Food Processors Association,
stated that the guidelines must be easily understood, easily
implemented, and must trigger behavioral change if they are to
contribute to public health. The goals of the Dietary
Guidelines should be to motivate and stimulate action on diet and
lifestyle by consumers.
Mr. Earl urged the Committee to place substantial emphasis on
"calories count" messages in addressing the balance between food
intake and physical activity. The National Food Processors
Association believes that it is critical to increase guidance on
physical activity, combined with positive, "how to eat" messages, as
opposed to negative, "what to eat" messages.
Mr. Earl stressed that there must be a commitment to assessing
consumer understanding of the Dietary Guidelines and the
effectiveness of the Dietary Guidelines in promoting behavior
change. Consumer education should then follow.
Mr. Earl urged the committee approach any consideration
of changing the focus of the guidelines from healthy
Americans to America's overweight and obese populations with
consideration to scientific evidence and effective change.
Mr. Earl urged that the Committee clearly articulate the critical
need for synergy among the Dietary Guidelines, the Food Guide
Pyramid, and food labeling. Metrics such as energy requirements,
physical activity, serving sizes, and nutrient standards should be
consistent across the
Dietary Guidelines and other communications tools. The
DRI values are scientifically sound and should be used for the
Dietary Guidelines, the Food Guide Pyramid, and for future food
nutrition labeling changes.
Dr. Elizabeth Pivonka, Produce for Better Health Foundation
(PBH), informed the Committee that PBH is the founding partner,
along with the National Cancer Institute, of the National Five-A-Day
for Better Health Program that encourages all Americans to eat at
least five to nine servings of fruits and vegetables each day.
PBH is a not-for-profit 501(c)(3) educational foundation, with
financial support from grants and volunteer contributions from the
fruit and vegetable industry, the public health community, and
concerned citizens.
Dr. Pivonka stated that science supports the important role that
fruits and vegetables play in reducing the risks of chronic diseases.
She highlighted three recommendations during her testimony for
strengthening the guidelines with regard to fruits and vegetables:
- The Committee should strengthen the fruit and vegetable
guideline to state, "Eat at least five to ten servings of fruits and
vegetables every day," with greater emphasis on eating fruits and
vegetables in a way that maintains their integrity as healthful
foods. Dr. Pivonka noted that replacing low-nutrient,
energy-dense foods with fruits and vegetables will help fight the
obesity epidemic, and that fruits and vegetables are an excellent
source of fiber.
- The Committee should include the concept of color as a way for
consumers to put into practice the otherwise vague concept of variety
and to expand their intake of traditional nutrients, as well as
phytochemicals. Dr.Pivonka mentioned the PBH's The Color Way
campaign as a platform for increasing consumption.
- The guideline for fruits and vegetables should be strengthened to
stress the importance of introducing fruits and vegetables in the
early years, in light of recent evidence that 25 percent of infants
and toddlers do not consume any fruits or vegetables.
Ms. Alison Kretser, Grocery Manufacturers of America (GMA),
stated that GMA recognizes that it has a role to play in combating
obesity and continues to seek opportunities to provide solutions.
GMA and its members believe it is important for Americans to
understand that to be healthy they must eat a nutritionally balanced
diet, be physically active, and moderate their food intake to match
their level of physical activity. GMA recommends that the
Committee change the name of the Dietary Guidelines to the
"Dietary and Physical Activity Guidelines."
Ms. Amy Myrdal, Dole Food Company, stated that Dole is a
long-time supporter of the National Five-A-Day Partnership, which
consists of government agencies, non-profit organizations, and
industry working collaboratively to increase consumption of fruits and
vegetables for better health. Ms. Myrdal stated that Dole is
concerned about the gap between recommended and actual fruit and
vegetable intake especially among children. She noted that
research demonstrates that children who eat the most fruits are least
likely to be overweight and that consumers generally understand the
importance of fruits and vegetables in a healthful diet, though they
fall far short of meeting the recommended number of servings.
Ms. Myrdal stated that consumers need to be provided with the
messages, tools, and support in order to meetthese recommendations.
Ms. Myrdal presented four recommendations to the Committee:
�
Provide a clear actionable guideline for fruits and
vegetables, such as "Consider eating at least five to nine, or five to
ten servings of colorful fruits and vegetables each day." Include
specific examples and simple tips for preparing and serving fruits and
vegetables.
�
Acknowledge consumer preferences and tastes in the
variety of product options available to consumers.
�
Include specific information on the role of fruits and
vegetables in weight management, providing essential nutrients without
excessive calories.
�
Encourage increased public/private collaboration to
maximize resources to conduct the scientific and consumer research
required to develop effective educational and promotional programs.
Dr. Joyce Nettleton, Alaska Seafood Marketing Institute,
stated that the Institute believes the scientific evidence supporting
a range of health benefits from the regular consumption of fish is
sufficiently abundant and convincing to warrant a recommendation to
the public to consume fish, particularly fatty fish, twice a week.
Dr. Nettleton cited three reasons for expanding dietary advice to
include regular fish consumption in the Dietary Guidelines.
First, the current
Dietary Guidelines fall short of ensuring adequate and desirable
intakes of long-chain omega-3 polyunsaturated fatty acids, or PUFAs,
because they are barely mentioned in the Dietary Guidelines.
Second, the proposed revision would make the Dietary Guidelines
more effective for women of childbearing age and most adults.
Seafood is the major dietary source of an essential fatty acid for
fetal and infant development, and the omega-3 long-chain PUFAs found
in fish are associated with significant reductions in the risk of
cardiovascular disease and mortality. Third, regular consumption
of fish would help offset the potentially excessive intake of omega-6
PUFAs, whose high levels compete with omega-3 PUFAs for the same
metabolic pathways and have been shown to be pro-atherogenic in large
amounts.
Dr. Nettleton stated that, in contrast to the recent DRI report,
the Institute believes the evidence indicates that current intakes of
omega-3 PUFAs are inadequate. The need for omega-3 long-chain
PUFAs is best fulfilled by the consumption of long-chain PUFAs; that
is, those with 20 carbons or more. These are the most
biologically active forms of omega-3s in cardiovascular health and, in
some cases, the only active forms.
The allotted time ran out before Dr. Nettleton completed her
testimony.
Dr. Margo Wootan, Center for Science in the Public Interest,
focused her remarks on six main points. First, the Center
believes that it is critical to provide clear advice about energy
balance throughout the Dietary Guidelines, including clear
advice about why and how to choose sensible portions.
Second, the
Dietary Guidelines should place greater emphasis on saturated fat
and should expand and strengthen the Dietary Guidelines' advice
about trans fat. That advice should be motivational as
well as scientifically accurate. The fat guideline should
encourage people to consume no more than 20 grams of saturated and
trans fat, combined. The advice about limiting dietary cholesterol
intake should be maintained.
Third, given rising sugar intakes, calorie intakes, and obesity
rates, the word "moderate" should be replaced with clear advice to
limit intake of refined sugars. A simpler guideline could read:
"Consume fewer soft drinks and sweets."
Fourth, the separate guideline on fruits and vegetables should
stress the quantity of fruits and vegetables to consume. The
supporting text should encourage eating a variety of fruits and
vegetables and provide advice about choosing healthy options.
Fifth, the current grain guideline should be changed to
something similar to: "Choose whole grains whenever
possible." Many grain products are leading sources of
saturated fat, trans fat, and refined sugars.
Americans need to consume different grains, not more grains.
Finally, the sodium guideline should state more clearly that
manufacturers and restaurants, not consumers, are responsible for most
added salts. That guideline also should include quantitative
recommendation for sodium intakes consistent with the daily values on
food labels.
Dr. Greg Miller, National Dairy Council, prefaced his
remarks by stating that the Council is funded by dairy farmers.
The Council believes that dietary guidance should be food-based. Dairy
foods make calories count by delivering a variety of important
nutrients that help reduce the risk of chronic diseases and aid in
weight management. Evidence indicates that three to four
servings of dairy foods might play a role in weight management
efforts, when coupled with a balanced, reduced-calorie diet.
The DASH trials and other studies have clearly demonstrated that a
balanced diet containing at least three servings of dairy foods a day
is useful in controlling blood pressure. This benefit is twice
as great in African-Americans.
Dairy foods are also important for bone health. Calcium intakes for
bone health are most likely to be met in a diet that provides three to
four servings of dairy foods a day. A review of USDA's technical
reassessment of the Food Guide Pyramid showed that several key groups
of people would not get sufficient calcium without increasing the
number of dairy servings. The Committee should evaluate the
potential negative impact of supporting fortified, high-calcium
sources that have fewer nutrients than dairy products. The
nutrient bioavailability of these products also is a concern.
In closing, Dr. Miller stated that dietary guidance should be
food-based because that is how people consume their nutrients.
Choosing foods wisely to provide balance, variety and moderation
should remain the cornerstone of the dietary guidance for the general
population.
Dr. Charles Baker, The Sugar Association, Inc., stated that
the Sugar Association represents U.S. sugar cane and sugar beet
growers and processors. It was established in 1943 to monitor
nutrition science and educate consumers.
The Association supports sugar as a safe, useful, and important
food ingredient, based on the totality of scientific evidence. Dr.
Baker stated that the Association shares the health community's alarm
about the rising rates of obesity, especially among children, and that
it
wished to address the growing momentum to connect negative health
outcomes such as obesity and nutrient displacement with the
consumption of added sugars.
During the debate of the 2000 dietary guideline on sugars, the
Sugar Association, along with many in the food industry, called for an
independent review of the complete body of scientific literature of
sugars to be undertaken by the National Academy of Sciences. The
NAS Report concluded that there is inadequate evidence of health risks
to establish an upper intake level for either total sugars, or added
sugars. The IOM review found that displacement was evident with
some micronutrients, but only in some population groups, and then only
after intake of added sugars exceeded 25 percent of daily calories.
Dr. Baker noted that the U.S. average intake of added sugars is 16
percent.
The IOM panel concluded that there is no clear evidence or
consistent association between increased intake of added sugars and
BMI. Experts acknowledge obesity occurs from energy imbalance.
The current emphasis on cutting carbohydrates and eliminating sugars
only obscures the significance of the caloric balance message.
Dr. Baker stated that our grandmothers' advice to "eat a little bit
of everything and then go outside and play" recognized the central
importance of moderation, portion control, and daily activity and
healthy lifestyles.
In conclusion, Dr. Baker stated that the Association respectfully
asks the Committee to maintain the scientific integrity of the
Dietary Guidelines for Americans by de-emphasizing the inordinate
focus on added sugars prevalent in the 2000 Edition.
Ms. Mary Young, National Cattlemen's Beef Association,
prefaced her remarks by noting that the Association is funded by beef
farmers and ranchers. She stated that the industry has responded
to public health recommendations by providing leaner cuts of beef.
Beef is now 20 percent leaner than it was 14 years ago. At least
19 cuts of beef meet government guidelines for lean. Twelve of
these cuts have, on average, one more gram of saturated fat than a
skinless chicken breast.
Ms. Young stated that the fatty acid profile of beef is commonly
misunderstood. Half of the fatty acids in beef are monounsaturated.
One-third of the saturated fat is stearic acid, which has been shown
to have a neutral or cholesterol-lowering effect. A study in the
Archives of
Internal Medicine showed that lean beef is interchangeable with
lean chicken and fish on blood cholesterol levels. Beef provides
nutrients that are beneficial for health through all life stages. It
is the number one food source of protein, zinc and vitamin B-12 in
American diets, the number two source of vitamin B-6, and the number
three source of iron and niacin.
Ms. Young cited a CSFII analysis showing that those who eat 3.6
ounces of beef each day are more likely to meet 100 percent of the
daily value for protein, iron, zinc and B vitamins. They are
also more likely to rate high on variety scores and to consume the
recommended number servings of vegetables.
Ms. Young concluded by stating that lean beef, like fruits,
vegetables, whole grains, and low-fat dairy, is a nutrient-dense food.
She stressed that dietary guidance that promotes naturally
nutrient-rich foods can be an insurance policy for future health.
Mr. Paul Weller, Apple Processors Association (APA), stated
that APA and its member firms support the 2000 Dietary Guidelines
and the Food Guide Pyramid, which highlight the importance of fresh
fruits and vegetables, as well as 100 percent processed fruits and
vegetables, in a balanced diet. He noted that APA provided
supporting research for its testimony in written comments that were
previously submitted to the Committee.
Mr. Weller stressed that it is important to distinguish 100 percent
fruit products from fruit sugar or fruit fat-blended products.
Mr. Weller noted that recent articles have urged caution in feeding
fruit juice to children, suggesting that high intakes of juice may
contribute to childhood obesity. The preponderance of research
has found no relationship between children's juice intake and short
stature or overweight. He encouraged the Committee to base its
recommendations on national food consumption data rather than small,
non-representative clinical studies to determine the relationship
between 100 percent fruit juice, and fruit product consumption in
childhood obesity.
Finally, Mr. Weller noted that fresh fruits and vegetables are not
always convenient or affordable. National recommendations should
include processed fruit products and 100 percent juices, which are
shelf-stable alternative sources of vitamin C, folate, potassium, and,
in some cases, calcium in fortified fruit products.
Ms. Kathy Means, Produce Marketing Association, noted that
her organization represents and is funded by produce marketers.
Ms. Means stated that the Committee should maintain and strengthen the
guideline on fruits and vegetables and should specify that consumers
should eat five to ten servings of fruits and vegetables a day.
In addition, the Committee should integrate and reinforce actionable
messages based on credible sound science and consistent messages about
fruit and vegetable consumption throughout the Dietary Guidelines
wherever possible.
Ms. Means then urged the Committee to encourage consumers to eat
fruits and vegetables instead of foods that are high in calories,
sodium and added sugars to gain health benefits and control weight.
The Dietary Guidelines
should stress consumption of whole foods and should specify that
whole fruits and vegetables, rather than food supplements, offer
health benefits from the synergy of each unique combination of
nutrients and phytonutrients that we know about, and those we have yet
to discover.
She stated that the
Dietary Guidelines should encourage consumers to feed children
fruits and vegetables to encourage good eating habits that will last a
lifetime, fight childhood obesity, and reduce long-term healthcare
costs for the future.
Finally, Ms. Means urged the Committee to develop a strong
communications program that will help get the word out to consumers
about the Dietary Guidelines, particularly with regard to
increased fruit and vegetable consumption through consumer messages
that are simple, well understood, specific and actionable.
Ms. Nancy Chapman, Soyfoods Association of North America (SANA),
noted that her organization is a trade association of soyfarmers,
soymanufacturers, processors, chefs, and educators. She
commended the 2000 edition of the Dietary Guidelines for
acknowledging the cultural diversity in American food choices and
presenting plant-based foods, such as soyfoods, as a good source of
several key nutrients. She stated that providing more examples
of soyfoods would make the
Dietary Guidelines more practical for many Americans.
Ms. Chapman noted that, in addition to providing important
nutrients, such as calcium, iron, fiber, and high quality protein, soy
has also been linked with lowered risk of heart disease and, possibly,
other chronic diseases. Soyfoods have been identified as an
important dietary factor in decreasing the risk for cardiovascular
disease by lowering LDL cholesterol, as well as increasing arterial
compliance. Emerging evidence, which has been submitted to the
Committee in the form of written comments, indicates that soyfoods may
also have a beneficial effect on bone health, diabetes, hypertension,
prostate and breast cancer, weight control, and menopausal symptoms.
Soyfoods from whole beans have become a fast growing part of the
American diet. In 2003, one in six Americans incorporated some form of
soy in their diet at least once a week, according to the United
Soybean Board. In closing, Ms. Chapman recommended that the
Dietary Guidelines should include a wide variety of soyfoods from
both traditional and modern processing.
Dr. Jeffrey Blumberg, Wyeth Consumer Health Care and Tufts
University, noted that nutrition status surveys and national
nutrition monitoring efforts consistently reveal that a significant
portion of the American population fails to meet the RDA for several
key vitamins and minerals. In addition to large segments of the
population that are particularly vulnerable, the general population
falls short of micronutrient goals due to typical American dietary
patterns.
Dr. Blumberg stated that while getting Americans to follow the
Dietary Guidelines
established by this Committee should remain the top priority for
nutrition policy, a daily multi-vitamin, multi-mineral supplement
could be an effective safety net to ensure that Americans are meeting
the recommended levels of micronutrients.
A growing body of research reveals an inverse association between
inadequate micronutrient intake and the risk of some birth defects and
several chronic diseases. The benefits of folic acid on neural
tube birth defects and of calcium and vitamin D on osteoporosis are
widely recognized. In other cases, the data are still emerging,
but the promise is clear.
Dr. Blumberg stated that the revised Dietary Guidelines
should recommend a daily multi-vitamin supplement. In 2000, the
Committee saw fit to recommend specific vitamin and mineral
supplements for certain at-risk populations. The recommendation
of a daily multi-vitamin for the population at-large in 2005 is
simpler to communicate, easier to comply with, less expensive, and
more effective in ensuring that all Americans meet all of their
micronutrient requirements.
Ms. Lynn O'Brien Nabors, Calorie Control Council, prefaced
her remarks by noting that the Calorie Control Council is an
international association of manufacturers of low-calorie and reduced
fat foods and beverages, including the manufacturers of a variety of
sweeteners, fat replacers, and low-calorie ingredients used in these
foods.
The 2000 Dietary Guidelines Advisory Committee acknowledged that
intense sweeteners are low in calories and the usefulness of these
products, as well as fat-free and low-fat dairy products, and hopes
the 2005 Committee will include a similar statement.
Ms. Nabors cited the Council's 2000 Light Survey, which found that
180 million adult Americans use low-calorie, sugar-free, and
reduced-fat products. Almost eight out of ten of these consumers
say that they would like additional light products. She stated
that all sweeteners and fat replacers that are currently available
have been thoroughly reviewed by the FDA. Although their safety
is well documented, a great deal of misinformation about these
ingredients circulates widely.
The American Diabetes Association (ADA) has stated that the
FDA-approved, low-calorie sweeteners underwent rigorous scrutiny and
were shown to be safe for the public, including diabetics and pregnant
women. ADA has also stated that the FDA provides assurance that
current fat replacers are safe to use in foods. Including similar
statements in the 2005 Dietary Guidelines would greatly assist
in minimizing consumer concerns related to sweeteners and fat
replacers.
Dr. Edward Siguel
stated that he specializes in essential fats, a term he coined to
represent the omega-3 and omega-6 families of fatty acids. Using
a method he invented to accurately measure essential fatty acid
deficiency, Dr. Siguel found that about 30 percent of adult Americans
are deficient in omega-6 fats, and about 70 percent are deficient in
omega-3 fats, using samples from the Framingham Heart Study and
several other populations.
Dr. Siguel stated that he has found that there is no scientifically
valid study regarding the nutritional requirements for essential fatty
acids. All the studies he has reviewed have incorrect data
because they do not accurately measure the different kinds of
essential fatty acids.
Dr. Siguel stated that the recommendations pertaining to trans
fats, saturated fatty acids, and cholesterol should be discarded.
The emphasis should be on total calories, grams per day of essential
fatty acids, and eating enough of other nutrients.
Dr. Amy Lanou, Physicians' Committee for Responsible Medicine
(PCRM), began her presentation by proposing several changes in the
way Americans eat. She recommended increasing consumption of
plant-based foods, including fruits, vegetables, grains, and legumes;
reducing reliance on highly processed foods; and limiting or avoiding
products of animal origin.
Dr. Lanou then offered several recommendations that PCRM believes
would strengthen the Dietary Guidelines. First, PCRM recommends
replacing the guideline, "Let the Pyramid guide your food choices"
with a more direct message, "Choose a diet built from plant foods."
Dr. Lanou stated that science clearly shows that diets built from
plant foods, vegetarian diets and vegan diets reduce the risk of
cancer, heart disease, hypertension, and diabetes, among other medical
conditions.
Second, PCRM recommends that the Committee make dairy products
optional and highlight the full range of calcium-containing foods in
the U.S. food supply. Dr. Lanou noted that many non-dairy
calcium sources have the advantage of being low in saturated fat and
high in fiber.
The allotted time ran out before Dr. Lanou completed her testimony.
Mr. Robert Guenther, United Fresh Fruit and Vegetable
Association, stated that the association is the produce industry's
oldest national trade association and public policy advocate for
producers, wholesalers, distributors, brokers, and processors of fresh
fruits and vegetables.
Mr. Guenther noted that fruit and vegetable consumption remain
below the recommended levels included in the last edition of the
Dietary Guidelines. His association strongly urges the
Committee to put forth new enhanced recommendations in this area.
Such guidelines should promote much needed behavior change based on
the scientifically based health benefits of a diet rich in produce.
Mr. Guenther briefly commented on three important issues that his
association believes should be considered as part of the revised
Dietary Guidelines. First, the Dietary Guidelines
should more clearly acknowledge the scientific findings that support
fruit and vegetables as a vital foundation of optimal health.
Second, the Dietary Guidelines
should include a measurable range of five to ten servings of fruit and
vegetables per day, which is consistent with USDA's proposed revision
of the Food Guide Pyramid and provides consumers with concrete
guidance. Finally, the Dietary Guidelines should help to
promote behavior changes that will support optimal health.
Dr. Mary Enig, Weston A. Price Foundation, recommended
abandoning the current Food Pyramid concept and returning the
Dietary Guidelines to a plan that stresses high-quality foods from
four basic groups. She stated that the Dietary Guidelines
should urge avoidance of processed foods containing refined and
partially hydrogenated vegetable oils; highly sugared foods,
especially those foods containing high fructose corn syrup; and
refined, highly processed protein isolates. The Dietary
Guidelines should encourage use of beneficial, unprocessed,
unrefined saturated and monounsaturated fats and oils. Also the
Dietary Guidelines should limit added sugars to no more than 10
percent of daily caloric intake.
Dr. Enig stated that using the Pyramid to select foods results in a
diet that is very high in carbohydrates and very low in natural fat.
The carbohydrates that are selected invariably are refined, and the
fats and oils are partially hydrogenated, high trans fats,
and/or very high omega-6 and missing omega-3. She noted that
diets high in refined carbohydrates lead to diabetes. Diets high
in trans fat or with excessive omega-6 interfere with glucose
and insulin handling and lead to vision problems in children and to
increased asthma, immune dysfunctions, heart disease, and cancer.
Adequate animal foods provide nutrients that are not found in diets
devoid of them. Diets devoid of natural saturates interfere with
omega-3 function.
The Foundation recommends eating high quality, unprocessed foods
from each of the following four groups: animal foods; grains and
legumes; fruits and vegetables, preferably fresh or frozen; and fats
and oils. The Foundation also recommends limiting intake of
sweets, white flour products, soft drinks, processed foods,
polyunsaturates, and partially hydrogenated vegetable fats.
Dr. Esther Meyers, American Dietetic Association
(ADA), noted that the Association is the world's largest
association for food and nutrition professionals. Her
presentation focused on three points that were included in
the ADA's written testimony.
First, ADA suggested that some of the controversy and confusion
regarding the fat and sugars guidelines might be avoided by replacing
the current guidelines with a guideline on nutrient density, such as,
"Foods that supply energy, but few nutrients, should be used sparingly
in the diet." This type of guideline would limit the confusion
regarding the high fat or high sugars foods and help clarify issues
surrounding energy balance and moderation.
Second, ADA recommended that the Dietary Guidelines continue
to focus on food and the whole diet rather than specific nutrients.
Some at-risk populations may require attention to specific nutrients
and supplements, but most people can achieve nutrient adequacy via a
balanced diet.
Finally, ADA emphasized the importance of consumer-friendly
messaging. The practice of consumer testing the guidelines prior
to publication should continue and should include both qualitative and
quantitative research. Public education on the Dietary
Guidelines is essential. The Dietary Guidelines should be
harmonized with the other nutrient education tools, such as the USDA
Food Guide Pyramid, the Nutrition Facts label, and the American
Diabetes Association Exchange List. For example, the Pyramid
serving size for juice is three-fourths cup, while the label says one
cup, and the Exchange List indicates one-half cup.
Dr. Alex Hershaft, Farm Animal Reform Movement (FARM), noted
that FARM is a national non-profit organization advocating plant-based
eating since 1976. It is funded by individual contributions and
has no food industry affiliation.
Dr. Hershaft stated that the nation's diet is shaped less by the
science-based guidelines of this Committee than by the profit-based
advertising claims of the food industry and the politically based
subsidy and regulatory programs of the USDA. He cited three
areas where he felt the Committee could correct this situation.
First, Dr. Hershaft suggested that government nutrition programs,
such as the National School Lunch Program, should be improved by
encouraging them to comply with the Dietary Guidelines.
Second, he suggested that the Committee should respond to diet
crazes that can have life-threatening consequences by appointing a
team to advise consumers of the long-term consequences of violating
the Dietary Guidelines.
Third, Dr. Hershaft urged the Committee to consider developing a
special edition of the
Dietary Guidelines for children. This edition should be
geared to children's nutritional needs, be graphically designed to
appeal to children, and should impress on food manufacturers, parents,
school administrators, and government officials their responsibilities
for our nation's health.
Dr. Diana Zuckerman, National Center for Policy Research for
Women and Families,
recommended that, in addition to focusing on the scientific issues,
the Committee should focus on how to influence Americans' eating and
exercise habits. She suggested that changing how serving sizes
are measured would make the Guidelines more accessible to consumers.
It would also be helpful if the Food Pyramid and Nutrition Facts
labels were consistent with each other, and with reality. Dr.
Zuckerman suggested creating a black box around calories on the
nutritional label, in an effort to get people to pay attention to the
calorie information.
Dr. Zuckerman stated that the food intake patterns should be
specified for sedentary individuals, as well as for those who
exercise. Presenting the two patterns side-by-side would create
an incentive for people to exercise more. A public information
campaign that is easy to understand, remember, and follow is also
needed.
Mr. Clay Hough, International Dairy Foods Association,
stated that IDFA is a trade association with over 500 members who
supply 85 percent of the milk, cheese, yogurt, and frozen desserts
sold in the United States. He presented new research findings
that reinforce the need for the
Dietary Guidelines to recommend dairy foods as part of a healthy
diet.
Mr. Hough stated that emerging evidence indicates that dairy
products help burn fat and enhance weight loss. Numerous studies
confirm that people who consume more dairy products are less likely to
be overweight or obese. These benefits of dairy calcium products
have been demonstrated in people of different ages, genders, and
races. Dairy calcium also impacts body composition, maintaining
muscle mass while lowering body fat, and the DASH study has shown it
can help reduce hypertension. For these reasons, the Dietary
Guidelines should recommend at least three servings of dairy a
day.
Mr. Hough noted that studies have shown that people diagnosed with
lactose intolerance can comfortably eat yogurt and cheese, and drink
milk in moderate amounts.
Mr. Hough stressed that non-dairy foods, such as soy beverages, are
not substitutes for dairy. Soy beverages are not natural sources of
calcium, and the bioavailability of calcium in soy beverages has been
found to be inferior to that in milk. These foods also lack the
overall nutrient profile of milk.
The current
Dietary Guidelines suggest that individuals between 18 and 50
years of age need two servings of milk daily. According to the
Institute of Medicine, the adequate intake of calcium for men and
women between ages 18 and 50 is 1,000 milligrams a day. In order
to achieve this, a person would have to consume three servings of
dairy per day. IDFA therefore strongly urges that the Dietary
Guidelines
recommend at least three servings of dairy a day for all people.
Dr. Gil Wilshire, Carbohydrate Awareness Council, Inc. (CAC),
informed the Committee that the CAC is a newly incorporated member
organization that is active in organizing the sector of the food
industry that produces controlled-carbohydrate foods.
Dr. Wilshire began by stating that the current
Dietary Guidelines and the Food Pyramid are based on
flawed data. Virtually every population-based or other
comparative study has failed to account for bias or the
confounding variables of trans fat and carbohydrate
consumption.
Dr. Wilshire cited recently published, randomized control
trials demonstrating that the increased intake of natural
dietary fats in the context of a normal caloric diet
improves the surrogate markers of atherosclerotic disease.
Low-carbohydrate diets produce lower insulin and higher
growth hormone levels in the blood, which has been shown to
aid in the maintenance of bone and muscle mass in the
elderly, and the promotion of lipolysis in individuals who
are overweight. Low-carbohydrate diets also delay the
onset of type 2 diabetes, improve the adverse effects of the
metabolic syndrome, and ameliorate symptoms of polycystic
ovary disease in women.
Dr. Wilshire stated that generous amounts of dietary
protein have never been proven to be harmful in persons with
normal kidney and liver function. He also stated that
there is no dietary requirement for carbohydrates. The
beneficial nutrients found in grain and potato products are
more easily derived from lower-carbohydrate food sources,
such as non-starchy vegetables, berries, and some fruits.
Dr. Wilshire stated that converging evidence from
numerous sources strongly suggests that proteins and
naturally occurring fats and oils are the indispensable
components of a healthy diet and should constitute the
majority of the foodstuffs consumed by the general
population. He therefore recommends reversing the
low-fat, high-carbohydrate recommendations that are
reflected in the current Food Pyramid.
Dr. Rui Hai Liu, Produce for Better Health Foundation and
Cornell University, focused his presentation on the dietary
benefits of the fruits and vegetables that contain significant amounts
of bioactive compounds. He stated that these foods may provide
desirable health benefits beyond basic nutrition, including reducing
the risk of chronic diseases such as cancer, cardiovascular disease,
Alzheimer's disease, and diabetes. There is strong scientific
evidence to support a recommendation to consume five to ten servings
of a wide variety of fruits and vegetables.
Dr. Liu stated that prevention is a more effective
strategy than treatment of the chronic disease. It is
estimated that one-third of all cancer deaths in the United
States could be avoided through dietary modifications, such
as increased consumption of fruits and vegetables.
Dr. Liu stated that whole foods provide additional
benefits that cannot be obtained from dietary antioxidants.
Current evidence indicates antioxidant nutrients alone
cannot explain observed health benefits of diets rich in
fruits and vegetables, because taken alone, the individual
antioxidants studied in clinical trials do not appear to
have consistent preventive effects. Laboratory studies
show that fruit and vegetable phytochemical extracts exhibit
strong antioxidant and anti-cancer activity.
Fruits and vegetables eaten in the recommended amounts
are safe. Dr. Liu therefore believes a recommendation
to eat five to ten servings of a variety of fruits and
vegetables daily is a proper strategy to reduce the risk of
chronic disease and to meet nutrient requirements for
optimum health.
Dr. Nathaniel Clark, American Cancer Association,
American Diabetes Association, and American Heart
Association, noted that the three organizations chose to
present comments together due to the huge toll that cancer,
diabetes, heart disease and stroke take on the American
public. Mr. Clark stated that these diseases are
largely preventable through healthy diets, physical
activity, and maintenance of a healthy weight, and he
presented the organizations' recommendations.
First, while dietary patterns are important, the quality
of food choices within each food group should also be
emphasized and attention should be given to the concept of
energy density.
Second, the Committee should make a strong statement
about the relationship between weight control and chronic
disease risk. Portion control should be emphasized
throughout the
Dietary Guidelines. Messages to limit refined grains and
foods high in fat and added sugar should be explicit.
The Dietary Guidelines must acknowledge that both
physical activity and calorie reduction are necessary for
successful weight loss and management.
Third, increasing scientific evidence indicates that the
type of fat in the diet plays more of a role than the total
amount of fat when it comes to reducing the risk of chronic
disease. Therefore, messages to eat a diet low in saturated
fat remain appropriate. Messages to reduce total fat
intake should be made in the context of calorie control.
Fourth, legumes and starchy vegetables should be shifted
from the vegetable and fruit group to the grain group.
Fifth, the Dietary Guidelines should emphasize the
importance of physical activity in promoting good health and
preventing chronic disease for both youth and adults.
Mr. Clark concluded by stating that the organizations
encourage the Committee to develop a complimentary document
for policymakers that would articulate policy changes that
can help support implementation of the Dietary Guidelines.
Ms. Cynthia Reeser presented her own independent
recommendations. She noted that she is a member of the ADA
and is actively involved in the work of the Vegetarian
Nutrition Dietetic Practice Group. Ms. Reeser stated
that the Dietary Guidelines are having a marginal
impact on addressing the growing number of adults and
children who are overweight or obese and proposed that the
Committee take a new approach.
Research has revealed that consumers want to know how
they will benefit from the food choices the Dietary
Guidelines
recommend and that their primary concern is weight management. In
2004, the recommendations of many diets are more popular
than the
Dietary Guidelines' conservative approach.
Ms. Reeser suggested revising and updating the "Aim for a
healthy weight" guideline to more clearly convey the short-
and long-term health and nutrition benefits and motivate
consumers. The Dietary Guidelines should also
provide clear, simple, and specific directions regarding
strategies and techniques that consumers can use to make
changes.
Ms. Reeser stated that the guidelines, "Choose sensible
portion sizes"and "Control portion size"presume that people
know what sensible portions are and how to control them.
She recommended visual portion references and noted that she
had provided specific suggestions in her written testimony.
Ms. Reeser closed by urging the Committee to encourage
increased consumption of whole plant foods, possibly by
creating a new guideline, "Build your meals around whole or
unrefined plant foods." She stated that beans, seeds, and
nuts deserve their own place on the Pyramid that is distinct
from the Meat group and that soyfoods also deserve more
emphasis.
Dr. Frances Taccone, International Five-A-Day
Federation, introduced her testimony by stating that
approximately 30 countries are now conducting fruit and
vegetable promotions like the U.S. Five-to-Nine Program.
The leaders of these national nutrition programs have formed
an international network called The Five-A-Day Federation.
In 2003, the Federation launched a collaboration with the
World Health Organization to develop a global fruit and
vegetable initiative as one strategy to reduce the burden of
non-communicable diseases and obesity.
Dr. Taccone stressed that the decisions of this Committee
have far-reaching global impact, especially in countries
beginning their Five-A-Day type programs. She
therefore urged the Committee to make the strongest possible
recommendation regarding the daily intake of fruits and
vegetables. Specifically, she urged the Committee to
set a new U.S. guideline, increasing the number of servings
of fruits and vegetables each day to five to ten.
Dr. Taccone noted that this recommendation would put U.S.
nutrition policy in synchrony with other developed nations
and the global health movement. The global health
trend is to recommend the goal, rather than the baseline.
This strategy sends a strong, clear message that a healthy
diet is based upon ample, not minimal, servings of fruits
and vegetables.
Dr. Taccone concluded by stating that neither the U.S.
nor the world can wait until all the research is finished
and all the evidence is evaluated. Assertive nutrition
policy that promotes preventive and self-health care
measures is needed now.
Dr. Katherine A. Beals, U.S. Potato Board,
focused her presentation on the limitations of a glycemic
index, with particular emphasis on data that had not been
presented by Drs. Krauss, Hu, and Slavin.
Dr. Beals noted that the glycemic index was originally
conceived as an inherent property of a carbohydrate-rich
food as opposed to a metabolic response of an individual to
a carbohydrate-rich food. Theoretically, the glycemic
index of a given carbohydrate should be constant from person
to person. In reality, the glycemic index can vary
considerably, depending on factors such as processing,
preparation, variety, and origin. She stated that the
glycemic index of potatoes can vary significantly, depending
on where they were grown.
Dr. Beals stated that the glycemic index was originally
developed to describe the rate of carbohydrate digestion and
absorption into the plasma. However, the blood glucose
concentration of plasma after carbohydrate consumption
represents the balance of both the entry and removal of
glucose from the blood. She cited a study conducted at
the University of Texas at Austin that compared the plasma
glucose kinetics of a low-glycemic index bran cereal to a
high-glycemic index corn flake cereal.
The allotted time ran out before Dr. Beals completed her
testimony.
Mr. Dan Snyder, Ms. Stephanie Fu, and Mr. Ken Buraker
presented recommendations for graphic changes in the Food
Guide Pyramid. The objectives of the proposed changes
were to emphasize the healthiest choices in each food
category, to show how all foods can fit, and to engage
consumers through technology.
Mr. Snyder first turned the Pyramid on its side so that
all food groups touch the base of the Pyramid, or the
foundation of the diet, and continue vertically to the top.
Gradations in shading were used within each vertical band,
with darker colors toward the base, where the most
nutrient-dense would be placed, and gradually lighter colors
going up toward the apex, indicating foods that are less
nutrient dense.
Mr. Buraker also proposed an interactive website,
FoodPyramid.Gov. Moving the cursor over certain band
areas within the Pyramid would show foods at various levels
of nutrient density. The allotted time ran out before the
team completed its testimony.
Dr. Richard Black, International Life Sciences
Institute of North America (ILSI N.A.), prefaced his
remarks by stating that ILSI N.A. is a non-profit 501(c)(3)
organization that seeks to bring scientists together from
industry, academia, and government to solve issues of mutual
concern to the public health. The majority of its
funding comes from industry. Dr. Black noted that ILSI
N.A. had submitted written comments and that he would
restrict his comments to three key points: evaluation of the
science; utilization of other expert reports; and food
safety.
Dr. Black encouraged the Committee to continue to take a
rigorous, evidence-based approach in evaluating the science
and determining the conclusions that can and cannot be made
from the evidence. He also noted that while nutrition
is a relatively young science that is still evolving,
consumers do not want nutrition advice to change. This
presents challenges for the Committee, which must defend its
recommendations, and for nutrition communicators, who must
educate consumers about the new advice.
Dr. Black encouraged the Committee to use contemporary
expert reports, such as the DRI report, as much as possible,
rather than reinventing the wheel.
Finally, Dr. Black urged the Committee to include the
important issue of food safety in the Dietary Guidelines.
He noted that while nutrition has long-term benefits for
health, food safety can have an immediate impact on
morbidity and mortality. The objectives are easy to
define, they are relatively easy to implement, and the
messages can be targeted to specific at-risk groups.
Dr. King thanked each individual who took time to prepare
the information that they shared with the Committee and
assured them that the Committee appreciated their
perspectives and insights. She stated once again that
public commentary was a continuous process and that
additional written comments could be sent to the address in
the Federal Register notice.
General Discussion of Overarching Issues
Dr. King noted that the eight Subcommittees would present their
reports on the second day of the meeting. She proposed that the
Committee use the remainder of the first day to discuss overarching
issues that go beyond the work of the Subcommittees.
Dr. King stated that the official charge to the Committee to come
up with dietary guidelines for reducing the risk of chronic disease
contained two additional endpoints: how to manage body weight,
and nutrient adequacy. She noted that there were three aspects
to weight management: maintaining current weight, losing weight
to achieve appropriate body weight, and sustaining a weight loss.
She asked whether the Committee wanted to consider all three of those
aspects and, if so, why or whether there were some aspects that
should not be considered in the report.
Dr. Pate stated that while he would not speak against any of the
three aspects, the most unique contribution that the Committee could
make would be to emphasize prevention of excessive weight gain.
Dr. Caballero agreed that the Committee should focus on one aspect,
while trying to look at the common elements among the three. He
noted that many of the issues that had been discussed during the day
including energy density, portion size, and physical activity were
related to avoiding excess weight gain and to maintaining weight loss.
In his opinion, it would be difficult for the Committee to give more
specific guidance for weight loss. There are many ways to lose weight
in the short term. The real difficulty is to maintain that
weight loss once the weight loss strategies are stopped.
Dr. Pi-Sunyer agreed that the most important aspect for the
Committee is prevention of weight gain. The American public
tends to gain weight every year, and prevention is particularly
important for children, adolescents, and young adults. He noted
that significantly more is known about prevention of weight gain than
about the other two aspects.
Dr. Clydesdale agreed with what had been said. However, he
thought it would be important to recognize that consumers are
confronted with many different approaches for losing weight. He
felt the Committee might be remiss if it did not at least comment
about weight loss, including the fact that the mechanism for weight
loss is not well understood.
Dr. Bronner supported the position of prevention, especially given
the epidemic in children. She suggested that the Committee could
look at the preventive mechanisms for each life stage that can be
found in the literature.
Dr. Kris-Etherton agreed that the major focus should be weight
control, but that it would be important to comment on weight loss.
Dr. Lupton agreed that prevention of weight gain should be the
primary focus. However, having chaired and defended the
Macronutrient Report, which did not deal with weight loss, she now
believes that it would be important to have a section that addresses
how to best lose weight, especially since the mechanisms for weight
loss and prevention may not be the same.
Dr. Nicklas agreed with Dr. Lupton that the methods for preventing
weight gain could be very different than the methods for weight loss.
She noted that the statement would have to be worded carefully and
that comments about diets should be made within a positive context.
Dr. King noted that in 2000, the Committee stated: "If you need to
lose weight, do so gradually." She asked if the Committee should
go further than that.
Dr. Caballero thought that even a rudimentary evaluation of all the
ways to lose weight would be beyond what people could absorb, but that
the Committee could say more than, "Do it gradually." He
suggested that rather than emphasizing the differences between weight
loss and weight maintenance, the Committee should emphasize the
commonality, which is energy balance physical activity, combined
with low- energy density food, healthy snacks, and portion size.
Dr. Kris-Etherton noted that the American Dietetic Association's
website has guidelines for healthy weight loss, or criteria for
evaluating a healthy weight loss plan. She suggested that
something like that would be very helpful for consumers.
Dr. Bronner cited research at Cornell that demonstrated that
failure to lose weight following pregnancy was associated with
increased BMI. She suggested that a discussion of the impact of
lifecycle transitions on weight might be an important knowledge-based
component to include in the report.
Dr. Pate stated that while he favored emphasizing prevention, he
agreed that the Committee could be perceived as having overlooked the
other two aspects if it did not at least comment on them.
Dr. Pi-Sunyer stressed that the Committee's report must be
evidence-based. He noted that most dieters come back to baseline
within at least three years. There is much more data with regard
to prevention than there is with regard to weight loss.
Dr. Kris-Etherton responded that the Committee could give some
guidance about the importance of making sure that a weight loss diet
is nutritionally adequate. There may be some other
commonalities, such as physical activity.
Dr. King asked whether Dr. Kris-Etherton was suggesting that the
report should contain general comments about the adequacy of the diet
and the role of physical activity, rather than getting into specifics
regarding certain proportions of calories coming from carbohydrate or
fat. Dr. Kris-Etherton agreed that this was what she was
proposing.
Dr. Caballero agreed that there is scarce evidence about which
approach works for long-term weight loss and maintenance. But he
noted that many studies have shown that those individuals who maintain
an active lifestyle after they lose weight are much more likely to
maintain that weight loss than people who just rely on diet.
Advice about physical activity would be important throughout the
Dietary Guidelines.
Dr. Clydesdale stated that it would be important to stress to
consumers that calories do count and that no combination of foods will
reduce the number of calories that those foods contain.
Dr. Camargo noted that there seemed to be a consensus that what
makes a diet effective is that people eat fewer calories. He
suggested stating that as a shared property of all effective weight
loss plans, without specifically mentioning brands, names, or
celebrities. For primary prevention and weight maintenance, the
message would emphasize energy balance.
Dr. King summarized the discussion by stating that this section of
the report would focus on prevention of excessive weight gain.
In the weight loss section, the report would continue to state, "If
you need to lose weight do so gradually," while also emphasizing the
importance of physical activity, energy balance, and the fact that
calories do count in achieving a healthy weight loss pattern.
She noted that Committee members had suggested focusing on common
elements that pertain to all three aspects of weight management.
She cited physical activity as one common element and asked for other
examples. Suggestions from the Committee included nutrient
density, energy density, portion size, and satiety.
There was some discussion regarding the relative importance of
nutrient density and energy density. Dr. Nicklas noted that the
Nutrient Adequacy Subcommittee would address that issue in their
report.
Dr. King noted that portion sizes had come up several times during
the day and that this issue affects both nutrient adequacy and the
risk of chronic disease. She asked whether there was adequate
scientific evidence to show that increased portion sizes have
contributed to the rise in obesity. Dr. Kris-Etherton cited a
study by Barbara Rolls that found that people who are given larger
portion sizes tend to eat more. She noted there is also evidence
from short-term studies showing that people don't compensate by eating
less they eat above what their calorie needs are for weight
maintenance. Dr. Nicklas cited two studies with children that
had similar findings, and an epidemiologic study that showed that
portion sizes have increased over time. She stated that it is
not clear whether people over-consume in one meal, or compensate less
at other meals, and she agreed that scientific literature on portion
size and BMI is lacking.
Dr. Caballero noted that while some people can compensate for
overeating over time, others find it more difficult to maintain energy
balance. He recalled that at its first meeting, the Committee
agreed that the individual should not bear the entire burden. It
is also important to create more favorable conditions for people who
are not genetically lucky to regulate their energy balance, and
portion size may play a role in this.
Dr. Weaver asked what the Committee could do about portion size,
beyond recommending that they be based on measurements. She
asked Dr. Hentges whether the Committee could make recommendations
about labeling. Dr. Hentges emphasized that the Committee's
recommendations must be evidence-based. He agreed with Dr.
Weaver that statements mandating the size of food packages would be
beyond the Committee's purview. He suggested that guidance on
effective portion sizes should be part of an implementation strategy
that would include industry and other partners.
Dr. Camargo proposed that part of the educational mission of this
guideline would be to teach consumers that serving sizes have changed
for many foods, perhaps with graphics showing how size and caloric
content have increased over time.
Dr. King reminded the Committee that in 2000, the committee said,
"Choose sensible portion sizes," with some guidance for how to do
that. Dr. Pate suggested that the Committee consider a much stronger
statement. He stressed that the statement should be based on the
scientific evidence and that the Committee would need to complete the
literature review. Dr. Clydesdale proposed a statement such as,
"To reduce caloric intake, reduce portion size."
Dr. Pi-Sunyer suggested that the concept might be easier to
understand if portion size differences could be equated with physical
activity expenditure. Dr. Kris-Etherton suggested that the
Committee look at the "Portion Distortion" quiz on the website of the
National Heart, Lung, and Blood Institute, which shows how portion
sizes have increased over the years and what that means in terms of
physical activity.
Dr. Pate cautioned that such an approach could have a negative
impact when trying to communicate the value of physical activity.
He noted that the daily mismatch between intake and expenditure when
one is looking to prevent future weight gain is not very great;
therefore, the dose of physical activity that could help to address
that is not very great. He was concerned about sending a message
that you could never perform enough physical activity to balance the
extra intake of a larger portion.
Dr. King asked whether portion size had any impact on nutritional
adequacy or any other endpoints, or if it was just an energy balance
issue. Dr. Camargo replied that portion size would have impact
on nutritional adequacy if the portion sizes were growing only in the
realm of the foods which were least nutritious which, unfortunately,
appears to be the case. Dr. King noted that this was related to
the issue of energy density, or nutrient density, and she asked Dr.
Weaver if her Subcommittee would discuss nutrient density in its
report. Dr. Weaver stated that the Subcommittee had identified this as
one of the topics that they would pursue next.
Dr. Bronner suggested that it might be helpful to use household
measures and bring the serving size recommendations more in line with
what people understand. Dr. King agreed that this would make sense.
She then asked whether satiety was an issue that needed to be
addressed in the report, and if so, how.
Dr. Weaver noted that the Nutrient Adequacy statements might
include a message to increase consumption of nuts and seeds and
legumes in light of recent studies showing the satiety value for nut
consumption. Dr. King noted that the Energy Subcommittee was
going to look at the issue of satiety with regard to breakfast.
Dr. Clydesdale stated that he would like to see the literature, if
any, on people who override the satiety of an energy-dense food.
He expressed concern that a message to eat more nuts would only be
helpful for those who do not have a weight problem.
Dr. King asked if any of the Subcommittees had addressed the issue
of nuts and satiety. Dr. Weaver said the Nutrient Adequacy
Subcommittee would address this issue. Dr. Lupton stated that
the Carbohydrates Subcommittee had a literature review on satiety in
fiber and fiber nuts.
Dr. Appel noted that the issue of satiety was relevant to many
aspects of the diet and that it should either be considered as a whole
or not at all. He also expressed concern about increasing the
workload of the Subcommittees.
Dr. King asked whether it would be possible to do a review of all
of the factors in the diet that could have an effect on satiety.
Several Committee members were in favor of conducting such a review.
Dr. Pi-Sunyer noted that the satiety literature was particularly
difficult. He was concerned that the Subcommittees would be
asked to review a large number of studies that would not provide
sufficient evidence for a specific recommendation.
Dr. Rattay noted that Dr. Barbara Rolls was one of the experts who
would present at the next meeting and suggested that she could discuss
the issue of satiety at that time. Dr. Appel expressed concern
about the lack of evidence-based studies regarding satiety and
suggested that it might be preferable to ask Dr. Rolls to focus on
energy density.
Review of Second Day Agenda
After ascertaining that the Committee had no further comments
regarding weight management, Dr. King briefly reviewed the agenda for
the second day of the meeting. She noted that the Committee
would focus on energy and the macronutrients in the morning, and would
discuss nutrient adequacy, ethanol, the lifecycle, food safety, and
fluid and electrolytes in the afternoon. At the end of the day,
the Committee would discuss specific tasks that would need to be done
prior to the next meeting in March in order to move from
nutrient-based scientific reviews to food-based conclusive statements
focused on reducing the risk for chronic disease.
Dr. King thanked the speakers for their presentations and recessed
the meeting.
(Recessed: 5:14 p.m.)
Thursday, January 29
(8:40 a.m.)
Dr. Janet King, DGAC Chair, welcomed the Committee and
observers to the second day of the meeting. She stated that each of
the Subcommittees would be presenting the findings of their work to
date to the full Committee for discussion and consideration.
Dr. King noted that when the Subcommittees began their work, they
identified research questions that could serve as the basis for
formulating dietary guidance to promote health. The research questions
were then categorized for clarification. "A" questions were
important questions for which summary tables already existed from
other authoritative reports. "B" questions were important
questions for which summary tables did not exist. These questions were
then prioritized by the subcommittees in order of importance and
summary tables were developed for those of top priority. "C" questions
were those for which there were either very limited data, which the
subcommittee knew to be insufficient to support science-based changes
in the guideline, or the question required an evaluation of either
published or publicly available data. The Subcommittee reports would
review the status of these research questions.
Dr. King then turned the floor over to Dr. Pi-Sunyer for the Energy
Balance presentation.
Energy Balance Presentation and Discussion
X. Pi-Sunyer, Lead
Dr. Pi-Sunyer introduced the other members of
Energy Balance and Weight Maintenance Subcommittee, which included Dr.
Appel, Dr. Caballero and Dr. Pate. He stated that the Subcommittee
would discuss three of the nine research questions during this
session. The remaining questions were still being reviewed.
Dr. Pi-Sunyer reviewed the Subcommittee's
research questions, indicated their category, and noted which
questions would be discussed during this presentation:
- Is
there a level of habitual physical activity that can be recommended
for prevention of weight gain? Many people may require more than the
recommended 30 minutes per day to prevent weight gain and the
question is, how much more. Does this differ by age, gender, race
and ethnicity, pregnancy and lactation? (Category A, to be discussed
by Dr. Pate)
-
How does a
high-carbohydrate, low-fat diet compare to a high-fat,
low-carbohydrate diet for maintaining weight in people with normal
BMIs? (i.e., does the population maintain weight better by eating
a diet composed of 40 percent fat compared to a diet composed of
20 percent fat?) How does a high carbohydrate, low fat diet
compare to a high-fat, low carbohydrate diet for weight loss (in
people with higher than normal BMIs)? (Category A, to be discussed
later in the day)
- What is the
relationship between fruit and vegetable consumption and BMI?
(Category A, to be discussed by Dr. Appel)
- What is the best
pattern for calorie consumption throughout the day? (i.e., three
meals a day, or six meals a day? Is breakfast critical to prevent
weight gain?) (Category B, literature review in progress)
- How much physical
activity is required to maintain weight loss? (Category A, to be
presented by Dr. Caballero)
- What is the
relationship between energy density and BMI? (Category A or B,
literature review in progress, to be discussed in March with Dr.
Barbara Rolls as an expert witness)
- Is there a level
of activity below which one cannot regulate appetite? (Category B,
literature review in progress, to be discussed in March)
- Does portion size
effect total energy intake? (Category A or B, literature review in
progress, to be addressed in March)
- What
is the most commonly reported leisure time physical activity modes
for those who report less than 150, 150 to 300, or greater than 300
minutes of leisure time/physical activity? What is the typical
physical activity pattern for individuals in these three categories?
(Category C, being evaluated from NHANES data)
Dr. Pi-Sunyer turned the floor over to Dr. Pate
to discuss Question #1: Is there a level of habitual physical activity
that can be recommended for prevention of weight gain?
Dr. Pate noted that, after extensive discussion,
the Subcommittee had concluded that it should continue to work on this
issue through the March meeting, for two reasons. First, the
Subcommittee identified an expert who will speak at that meeting about
current efforts to review and update the prevailing adult physical
activity recommendation. Second, an expert panel recently met under
the auspices of the Centers for Disease Control and Prevention (CDC)
to consider recommendations on physical activity for children and
adolescents. The panel's draft report is expected prior to March
meeting.
Dr. Pate noted that the 2000 Dietary
Guidelines endorsed or incorporated the then-prevailing adult and
youth physical activity recommendations. The Subcommittee felt it
would be important to hear from those groups regarding the progress on
potential modification or updating of the current recommendations.
The central question is whether the Dietary
Guidelines should recommend something more than 30 minutes daily
of moderate intensity physical activity for the specific purpose of
preventing excessive weight gain. There is considerable literature on
this issue that has been reviewed extensively by other groups and
expert panels. The Subcommittee is reviewing individual studies as
well as those consensus documents to determine whether or not the
conclusions of those panels are sufficient for the basis of a
recommendation.
Dr. Pate stated that the tentative thinking of
the Subcommittee is that there is at least substantial, if not
definitive, evidence to suggest that many persons need more than 30
minutes of physical activity daily to prevent excessive weight gain.
The issue that needs to be resolved prior to the March meeting is
whether or not some specific number of minutes of moderate to vigorous
physical activity per day can be pointed to as particularly important
for the prevention of excessive weight gain.
Dr. Pi-Sunyer thanked Dr. Pate for his summary
and called on Dr. Caballero to address Question #5: How much physical
activity is required to maintain weight loss?
Dr. Caballero stated that there is a great deal
of evidence in this area. A number of studies have information on
individuals who have lost weight and have been followed for up to five
years. Their final outcome in terms of body weight was related to
patterns of activity, as well as diet and other factors. The
literature and consensus statements of the past several years are less
contradictory than for never-obese individuals.
Two important conclusions emerged from the review
of the literature and consensus statements. First, the contribution of
physical activity to the weight loss process is relatively modest.
However, once an individual has achieved a weight loss, the inclusion
of a physical activity program, or the existence of a physical
activity pattern during the following months or years is consistently
associated with better maintenance of the post-obese weight.
The Subcommittee believes that two factors are
responsible for these findings. First, the level of physical activity
helps the individual maintain a negative energy balance and does not
result in weight gain. Second, the routine of physical activity also
helps in other aspects of maintaining weight, such as watching your
diet. In general, individuals who have a more structured approach
after they lost weight are more successful in maintaining that
weight.
Dr. Caballero noted that there is also general
consensus that the amount of activity required to maintain weight in a
formerly obese person is higher than for an individual who was never
obese. After reviewing the literature, the Subcommittee tentatively
reached the conclusion that an individual who has reduced his or her
weight would require 60 to 90 minutes a day of moderate activity in
order to avoid weight gain. He also pointed out that in many of the
follow-up studies, the differences in diets, or energy intake, were
not substantial; therefore, the main factor in weight maintenance
after weight loss is physical activity.
Dr. Pi-Sunyer thanked Dr. Caballero and turned
the floor over to Dr. Appel, who addressed Question #3: What is the
relationship between fruit and vegetable consumption and BMI?
Dr. Appel noted that this question was also a
work in progress. There are many observational studies associating
weight with BMI, but most of these are cross-sectional studies; there
are very few longitudinal studies. To date, four clinical trials have
attempted to identify whether increased consumption of fruits and
vegetables leads to weight loss among individuals who are overweight.
Unfortunately, most of those trials do not isolate fruits and
vegetables from other changes in behavior. Dr. Appel stated that it
may be difficult to isolate a specific effect of fruits and vegetables
on BMI, but he hoped to be able to expand on this at the next meeting.
Dr. Pi-Sunyer
turned the floor over to Dr. King for open discussion.
Discussion
Dr. King opened the discussion by asking Dr. Pate
and Dr. Caballero to clarify whether the 30-minute recommendation for
physical activity was for weight loss or preventing weight regain. Dr.
Pate stated that this recommendation evolved from a collaborative
project conducted by the CDC and the American College of Sports
Medicine (ACSM). It was included in the Surgeon General's report in
1996 as well as the report of an NIH conference around the same time.
In all cases, the panels concluded that 30 minutes of at least
moderate intensity activity daily was appropriate. However, those
reviews focused largely on the prospective epidemiologic studies
looking at chronic disease outcomes and not prevention of weight gain.
The IOM macronutrient panel that made the 60-minute recommendation
specifically considered prevention of weight gain. Dr. Pate noted that
the challenge is to balance the two considerations, so that whatever
recommendation is included in the Dietary Guidelines is
appropriate and is stated in a manner that is not confusing to the
public.
Dr. Caballero reminded the Committee of the
difference between a recommendation and a requirement. The requirement
could be 60 minutes, but the Dietary Guidelines could recommend
that the goal for the next five years is at least 30 minutes for the
majority of the population. He stated that panels that endorsed the
30-minute recommendation acknowledged that more activity provides more
benefits, but 30 minutes was considered to be a reasonable goal for
the majority of the population. Dr. Pate concurred that the 30-minute
recommendation was selected because it has been consistently found to
provide benefit. It has never been presented as a minimum or optimal
level of physical activity, nor has been presented as a limit. He
expected that the effort to update the 30-minute recommendation may
highlight the fact that there is additional benefit associated with
higher levels of activity, in terms of both total dose and intensity.
There was some discussion among Committee members
as to whether the recommended amount of physical activity could be
accumulated in short bouts. Dr. Pate stated that the CDC-ACSM
recommendation did sanction accumulating physical activity in bouts as
short as 10 minutes in duration, based on the experimental exercise
training literature. More recent studies have found the same
physiologic effects with bouts as short as five minutes, accumulating
to 30 minutes. He noted that there is a need for better clarification
of the baseline upon which the 30 minutes sit. Most experts would say
that is on top of normal, day-to-day physical activity associated with
the normal American lifestyle.
Dr. King asked if the Subcommittee anticipated
coming up with a suggested range for physical activity somewhere
between 30 to 90 minutes, with a graphic showing the benefit of
exercise at different levels. Dr. Pi-Sunyer said they would certainly
come up with a range, with or without a graphic.
Dr. Clydesdale asked if any literature existed
regarding how best to make recommendations in order to elicit optimal
behavior change. Dr. Pate acknowledged that the health communication
aspect was complicated but essential. He stated that a group at CDC
was working on ways to communicate these messages to the public, but
the issue of how to effect behavior change remains elusive. Physical
activity behavior in this country has not changed very much, despite
the effort that has been invested in encouraging those changes.
Dr. Go asked whether the Subcommittee would put
the energy requirement or intakes as the numerator or denominator in
relation to physical activity. Dr. Pate replied that while the
Subcommittee's primary concern is energy balance, it was not
interested in energy balance at a very low-level of energy turn over.
He expected that the Subcommittee would endorse energy balance based
on a level of physical activity that is consistent with good health.
Dr. Caballero noted that the Subcommittee had
defined energy requirements as the level of energy that maintains a
stable healthy body weight and a level of physical activity consistent
with good long-term health.
Dr. Weaver asked if there was evidence suggesting that monitoring
weight or activity levels influences behavior. Dr. Pate said that
monitoring is supported by the intervention literature to a certain
extent. There was some evidence that pedometers lead to better
adherence to increased physical activity, though he did not think the
Subcommittee would be that specific in its recommendations.
Dr. King asked if the Subcommittee was proposing
30 minutes of physical activity every day, most days, or some days.
Dr. Pate replied that the data suggests that it should be at least 30
minutes each day, averaged over the week. He noted that the CDC-ACSM
guideline was phrased, "preferably all days of the week," to
communicate that physical activity should be a regular part of one's
life. The CDC has operationalized that to mean five or more days per
week.
Dr. Appel noted that moderate and vigorous
activity had been grouped together and asked whether the
recommendation would be modified for those whose activity level was
already quite high. Dr. Pate replied that it would make sense to
indicate that the minutes required would be fewer if the activity is
more vigorous and that the modification to the earlier CDC-ACSM
Guideline would probably attempt to make such a distinction.
Dr. Camargo raised the point that it is more
difficult for people to keep track of how much exercise they are
getting when moderate physical activity is considered acceptable. Dr.
Pate agreed that moderate activity is more difficult to measure and
that it is also difficult to communicate the difference between
moderate physical activity, which has been shown to have health
benefits, versus light activity, for which the evidence is not clear.
Dr. King reminded the Committee that it had
agreed to address the issue of preventing excess weight gain and to
make some general comments about how to lose weight if that is
necessary. She asked if physical activity was an effective way to lose
weight. Dr. Pi-Sunyer replied that it was not. Dr. Pate stated that
physical activity as a part of a weight loss regimen may make a modest
contribution, but it is not a major factor. Dr. Caballero stated that
physical activity was more important in the maintenance phase. He
suggested that those who exercise while they lose weight establish a
routine and increase their capacity to exercise. Dr. King noted that
the recommendations should include a comment that it is important to
establish a pattern of physical activity as part of a weight loss
regimen.
Dr. Pate stated that there was fairly consistent
literature indicating that those who exercise as a part of a weight
loss regimen tend to lose less lean weight than those who diet only.
During the maintenance phase, the greater lean weight would contribute
to a higher basal metabolic rate and overall greater energy
expenditure.
Dr. Pi-Sunyer emphasized the Subcommittee's
belief that physical activity must be a major part of the
communication effort regarding the Dietary Guidelines, whether
as part of the Pyramid or through another mechanism. Dr. King agreed
and assured the Subcommittee that the report would include a strong
statement to that effect.
Dr. King thanked the Subcommittee members for
their work and congratulated them on their progress. She reminded the
Subcommittee that they had been given the additional task of including
some discussion of an appropriate plan for losing weight, in a general
context. She then turned the floor over to Dr. Kris-Etherton and the
Fatty Acids Subcommittee.
Fatty Acids Presentation and Discussion
P. Kris-Etherton, Lead
Dr. Kris-Etherton introduced the other members of
the Subcommittee, which included Dr. Camargo, Dr. Go, and Dr. Nicklas.
She stated that the presentation would include a summary of the
Subcommittee's research questions and the priority assigned to each;
review of a sample summary table for the research relative to
metabolic syndrome; the status of the literature search; the areas in
which the Subcommittee had requested additional analysis; and a
discussion of next steps.
Dr. Kris-Etherton began with a review of the
Subcommittee's "A"-ranked questions. The Subcommittee identified two
research questions related to cancer: What is the relationship between
fat and cancer? What is the relationship between fatty acids and the
fatty acid ratio in different cancers? Dr. Kris-Etherton noted that
the Subcommittee was gathering that information from the National
Cancer Institute.
The next question identified by the Subcommittee
was: What is the effect of total fat to carbohydrate ratio on
cardiovascular disease? The Subcommittee hoped to make a contribution
by determining whether the fatty acid ratios, taking into account
dietary protein, and physical activity play any role.
The Subcommittee determined that trans
fatty acids needed investigation. The trans questions are: What
is the effect of sources of trans fatty acids (naturally
occurring, man made, CLA) on lipids and cancer? Dr. Kris-Etherton
stated that that information appears in the DRI report.
Another topic of importance was omega-3 fatty
acids. The question was: What is the effect of sources of omega-3
fatty acids on bioavailability and blood lipids? Dr. Kris-Etherton
stated that a report on "Effects of Omega-3 Fatty Acids on
Cardiovascular Risk Factors and CVD" is pending from the Agency for
Healthcare Research and Quality in the U.S. Department of Health and
Human Services.
The Subcommittee identified several important "B"-ranked questions on which it was gathering information. They were
particularly interested in how fat and fatty acid ratio comes into
play with respect to these research questions, because very little had
been done in this area.
The first question was: What is the effect of
total fat to carbohydrate ratio on metabolic syndrome? Dr.
Kris-Etherton stated that she would go over the table that the
Subcommittee prepared and summarize the studies they had
reviewed to date relative to this question.
The second question was: What is the effect of
total fat to carbohydrate ratio on overweight and obesity? Dr.
Kris-Etherton stated that a new Subcommittee would be formed to
address the issue of macronutrients.
The third question was: What is the effect of
total fat to carbohydrate ratio on cancer? The Subcommittee was
working with NCI on that topic.
The fourth question was: What is the effect of
total fat to carbohydrate ratio on nutrient adequacy? The Subcommittee
requested data on this from USDA.
The fifth, and final, question in this category
was: What is the effect of the total fat to carbohydrate ratio on
diabetes? The Subcommittee believed that these data were in the IOM
DRI Report.
Dr. Kris-Etherton then discussed the status of
the Subcommittee's data analysis pertaining to the effect of total fat
to carbohydrate ratio on metabolic syndrome. The Subcommittee feels
that it has a robust database to look at this question. It reviewed
six observational studies published between 1999 and 2003 for a total
of 12,270 subjects and 18 clinical trials reported between 1992 and
2003 on 797 subjects. The studies were conducted in Australia, China,
Denmark, Finland, France, Italy, Spain, Sweden, the United Kingdom,
and the United States, providing a global perspective on the issue.
More than half of the clinical studies were published in the past
three years. The template prepared by the Subcommittee to review the
clinical trials included the citation, the design, populations,
groups, outcomes, duration, baseline level for the different
endpoints, results, and relevant comments.
Given that the IOM has recommended 20 to 35
percent of calories from fat, and given that a guiding principal of
the Committee is to achieve nutrient adequacy, the Subcommittee wants
to look at variations in food patterns that would meet nutrient
adequacy at various levels of fat within the recommended range. The
Subcommittee is also asking how the omega-3 and omega-6 ratio, ALA
levels, and EPA and DHA levels relate to different food patterns
relative to different amounts of total fat. Dr. Kris-Etherton noted
that data pertaining to these questions are forthcoming from USDA.
Dr. Kris-Etherton stated that the Subcommittee
would develop a base diet by removing all added fat and then
manipulating other food groups to see what could be achieved in terms
of nutrient adequacy. The ultimate goal is to come up with a variety
of nutritionally adequate food patterns that meet macronutrient goals
and fatty acid targets.
Dr. Kris-Etherton identified a number of
additional questions that are being considered by the Subcommittee:
- What happens when we try to plan diets that have 35
percent calories from fat? Can they be planned without exceeding
calorie needs? What dietary changes would be needed to accomplish
this, while maintaining energy balance and meeting all nutrient needs
and fatty acid targets?
- What is the impact on nutrient and calorie intake of
increasing nut consumption?
- What is the impact on other nutrients in the diet if the
food patterns incorporate two servings of fish per week?
Dr. Kris-Etherton stated that the Subcommittee
feels it can make two definitive conclusions at this point: First,
trans fat, saturated fats, and cholesterol raise the total to HDL
cholesterol ratio. Second, recommending moderate fat within the 20 to
35 percent of calorie range is consistent with the DRIs for
macronutrients.
She also noted that many questions still remain
for the Food Guide Pyramid. First, USDA has questions about what
should be classified as solid fat. In particular, it is unclear
whether soft margarines should be classified as solid fat, or if their
fatty acid profile would justify classifying them as a liquid fat. The
issue of total fat relative to total fat across the lifecycle is
important. The Committee needs to decide whether to make specific
quantitative recommendations regarding saturated fat, trans
fat, and cholesterol (Dr. Kris-Etherton pointed out that the IOM
stated that these should be kept as low as possible, but did not make
specific recommendations). A benchmark is needed for diet planning and
for nutrition labeling. There is the issue of whether the cholesterol
recommendation should be made in terms of a set amount (i.e., less
than 300 milligrams a day) or in terms of amount per 1,000 calories.
And many questions remain regarding types of fats and fatty acids in
particular, what recommendations should be made for omega-3 fatty
acids, including EPA and DHA, omega-6 fatty acids, and monounsaturated
fatty acids.
Dr. Kris-Etherton then opened the floor for discussion
Discussion
Dr. King asked Dr. Kris-Etherton to expand on
what the Subcommittee's conclusive statements might be. Dr.
Kris-Etherton stated that they would be consistent with the current
Dietary Guidelines. That is, to decrease saturated fatty acids and
cholesterol. The Subcommittee might want to include a statement to
decrease trans fatty acids, within the context of a diet that
is moderate in total fat.
Dr. Appel asked whether the total cholesterol to
HDL cholesterol ratio or LDL should be used as the benchmark. He noted
that studies are coming out that show high carbohydrate diets reducing
HDL, but that research tends to focus more on LDL. Dr. Kris-Etherton
stated that the Subcommittee had used the total to HDL ratio because
it was new, but she recognized that LDL was the established standard
used for national cholesterol education programs.
Dr. Kris-Etherton asked other Subcommittee
members to comment on the conclusions. Dr. Nicklas stated that the
Subcommittee had looked at potentially adopting the DRI recommendation
that trans fatty acids should be as low as possible, with the
caveat that it should be within the context of the recommended food
patterns. The Subcommittee also considered the question of whether
cholesterol should be adjusted for energy intake, similar to
macronutrients. Cholesterol recommendations have been less than 300
milligrams. However, a very low percentage of children's diets exceed
300 milligrams, simply because they do not eat the same amount of
calories as adults. The Subcommittee will consider this. The
Subcommittee will discuss these issues and other questions pertaining
to food patterns with the Nutrient Adequacy Subcommittee.
With regard to the issue of solid fats, Dr.
Nicklas noted that soft margarines are combined with oils in the food
patterns. The Subcommittee asked if it was appropriate to group
margarines that contain trans fatty acids with those that are
made with canola oil or other unsaturated fatty acids. Many companies
are replacing the trans fatty acids in stick margarines with
stearic acid. The Subcommittee needs more information on the extent to
which this is occurring before it makes a recommendation as to how to
classify margarines.
A final issue was the fact that the DRIs included
two ranges for percentage of calories from fat 20 to 35, or 25 to 35,
depending upon age and gender. Dr. Nicklas stated that the Nutrient
Adequacy and Fatty Acid Subcommittees would consider whether the
Dietary Guidelines should include two separate ranges or whether a
single range could be recommended.
Discussion ensued as to whether 20 percent fat
could be considered moderate, or whether that should more accurately
be considered a low-fat diet, especially for younger age groups.
Several Committee members suggested that the Dietary Guidelines
could simply present an acceptable range, without describing it as a
low, high, or moderate amount of fat.
Dr. Caballero stated that it was his
understanding that more and more products have reduced or eliminated
trans fatty acid. He was concerned about placing too much
emphasis on something that represents a small percentage of daily
calories when there are so many important messages that must be
included in the Dietary Guidelines. Dr. Kris-Etherton replied
that in developing benchmarks and possible numbers, the Subcommittee
would need to decide whether to put saturated fats and trans
together, or whether to establish a separate recommendation for each
type of fat.
Dr. King stated that if the trans fat
content of the diet is shifting downward, a specific recommendation
might be out of date before the report even comes out. She suggested
that it might be more reasonable to recommend keeping it as low as
possible, without stating a number.
Dr. Pi-Sunyer asked how the Subcommittee proposed
to deal with monounsaturates. He expressed concern that
recommendations to increase consumption of energy-dense foods such as
nuts and olive oil would result in higher energy intake. Dr.
Kris-Etherton replied that this issue would be clarified when the
Subcommittee examines the food patterns that USDA is developing for
various levels of fat. She stated that the Subcommittee would follow
the recommendation of the National Cholesterol Education Program that
monounsaturates should not exceed 20 percent.
Dr. Kris-Etherton noted that when people think of
low energy dense diets, they automatically think of low-fat diets.
While that can be the case, a moderate fat diet that is high in fruits
and vegetables, plus good fats, can be low in energy density.
Dr. Lupton returned to the subject of stearic
acid. She noted that the hypothesis had always been that although it
is a saturated fatty acid, stearic acid is non-atherogenic. However,
she believed that the literature was fairly divided. She suggested
that it would be appropriate to revisit the literature now that
stearic acid is becoming more prevalent in the food supply. Committee
members had differing views regarding that suggestion. Dr.
Kris-Etherton stated that in addition to looking at the market share
for stearic acid, it would be important to look at the point of
comparison because stearic acid raises cholesterol compared to
linoleic acid but has a neutral effect compared with carbohydrate.
Dr. King stated that this section of the report
seemed extremely complicated and asked how the Subcommittee would
present all of the information to the public. Dr. Kris-Etherton stated
that they were planning to develop different food patterns that would
allow a great deal of flexibility in diet choices.
Dr. King asked Dr. Nicklas to clarify her concept
of the cholesterol/energy ratio. Dr. Nicklas reiterated that children
do not consume enough calories to exceed the 300 milligram
recommendation. There has been some discussion as to whether
cholesterol should be adjusted for energy intake as other
macronutrients are. The Subcommittee will be examining this.
Discussion ensued as to whether it was important
for children to limit their cholesterol intake. Dr. Nicklas stated
that there are a number of nutrients that may not be applicable for
the younger age groups or for the elderly and proposed to address that
issue in the Nutrient Adequacy presentation. Ultimately, it would be
important for the food patterns to be consistent with the
recommendations and provide nutrient adequacy.
Dr. King reminded the Committee that the goals
for the Dietary Guidelines are: (1) to manage body weight; (2)
to achieve nutrient adequacy; and (3) to reduce the risk of chronic
disease. If there are some important issues around the cholesterol
intake of children with regard to one of those three goals, the
Committee should make a definitive statement.
Dr. Appel raised the issue of omega-3 and asked
whether there was sufficient evidence to support a recommendation to
increase consumption of fish. He noted that there are some clinical
trials of omega-3 with regard to secondary prevention, but only
observational data when it comes to primary prevention. Dr.
Kris-Etherton replied that all but one of the studies the Subcommittee
had reviewed showed health benefits of about 500 milligrams a day with
regard to prevention of heart disease. The Subcommittee would work
with the food patterns being developed by USDA to see what impact fish
consumption would have on the total diet. She noted that there is a
growing database showing health benefits of ALA. Food sources of ALA
include walnuts, canola oil, flax seed, and soybeans.
Dr. King asked if the Subcommittee thought it
would be necessary to make a comment about the type of dairy products
that are chosen, in terms of fat content. Dr. Kris-Etherton replied
that the food patterns are based on the lowest-fat choices within the
different foods groups, with a daily allotment for fats within calorie
levels to maintain energy balance. There will be a budget for both
calories and fat. The fat budget c an be used for higher-fat foods in
any food group. The most flexible way of presenting it is to start
with the lean and decide where to add.
Dr. King asked Dr. Clydesdale whether he had any
food safety concerns regarding the recommendations of two servings per
week of fish. Dr. Clydesdale stated that the Subcommittee was taking
its lead from the FDA's Food Advisory Committee. That body recently
recommended that there be no warnings put on fish until we learn more
about the specific types of mercury and in what species that mercury
exists. He noted that limiting or eliminating fish could have the
unintended consequence of removing a good source of many other
nutrients.
Dr. King
commended the Fatty Acid Subcommittee for doing an excellent job
delineating a vast array of issues.
(Break, 10:15-10:30)
Carbohydrates Presentation and Discussion
J. Lupton, Lead
Dr. Lupton acknowledged the members of the
Subcommittee Dr. Clydesdale, Dr. Pate, and Dr. Pi-Sunyer and thanked
the staff, including lead staff member, Joan Lyon, and Dr. Pamela
Pehrsson, who helped with review of fiber literature.
Dr. Lupton informed the Committee that she had
organized the Subcommittee's nine research questions into five
categories: 1) carbohydrate intake and obesity; 2) whole grains versus
refined grains; 3) the significance of added sugars to health; 4)
carbohydrate intake and disease specifically coronary heart disease
and diabetes, and the related issue of glycemic response; and 5) the
overall significance of fiber in the diet.
Category 1 included two research questions: What
is the relationship of carbohydrate intake to obesity? Is one ratio of
carbohydrate to fat to protein better able to sustain a healthy BMI
than another? Dr. Lupton noted that these issues would be taken over
by a new subcommittee on macronutrient ratio, which would include
members of the Carbohydrate Subcommittee. The findings of that
Subcommittee would be discussed at a future meeting. Dr. Lupton stated
that the Carbohydrate Subcommittee had identified a number of
consultants to address certain issues, including Dr. Slavin, Dr.
Krauss, and Dr. Hu.
Category 2 included one research question: Is
there a measurable difference to human health between whole grain
consumption and refined grain consumption? Dr. Lupton noted that
Dr. Slavin had addressed that issue in detail
during her presentation.
Dr. Lupton stated that Category 3 the health
effects of added sugars was probably the most contentious area. The
Committee would need to document any proposed changes to the
recommendations in the strongest fashion with evidence-based research.
The first question, was: Is there a way to quantify the level at which
added sugar consumption may negatively impact human health?
Specifically, the Subcommittee wanted to determine if there was any
evidence that added sugar consumption was associated with decreased
micronutrient intake or increased weight. The Subcommittee added
another question that may or may not prove relevant: What is the
relationship of fructose intake to human health?
Category 4 included two research questions: What
is the relationship of carbohydrate intake to diabetes and heart
disease? How does the glycemic response relate to disease, if it does?
Category 5 included the two remaining questions:
Does consumption of high fiber foods affect satiety? Should specific
types of fibers be recommended to improve laxation?
Dr. Lupton stated that she would review the five
categories and their associated questions, with a focus on the status
of research in each area, the Subcommittee's thoughts in that area,
and directions for future work. She requested input from the Committee
as to whether the Subcommittee was on the right track.
Dr. Lupton noted that the Subcommittee made
several discoveries at the outset of their work. The first was that
the literature on definitions of carbohydrates is especially
confusing. Definitions differ from one paper to another, and some
papers do not specify what is included in the definition. As a result,
it is difficult to determine the ramifications of carbohydrate level
in the diet. Dr. Lupton recommended that the report include a glossary
that would define specific attributes of carbohydrates.
The issue of glycemic carbohydrate versus
available carbohydrate was also confusing. The Food and Agriculture
Organization recommends glycemic carbohydrate, which it defines as
providing carbohydrate for metabolism. Others have a different
definition.
Dr. Lupton noted that there are also various
definitions of dietary fiber. Some researchers specify fiber that is
intact from foods, while others include fiber that is synthesized in
the laboratory. The issue of whole grains versus refined grains versus
enriched grains is another area where greater clarity is needed.
Dr. Lupton stated that when the Subcommittee
began its literature review it quickly discovered that its research
questions needed to specify the type of carbohydrate. The question of
whether carbohydrate intake affects obesity then becomes a series of
questions: Do sugars affect obesity? Do starches or fiber, or whole
grains versus refined grains, or high glycemic foods versus low
glycemic carbohydrates affect obesity? The various types of
carbohydrates need to be treated as separate entities, because sugars
and fiber can have the opposite effects.
Dr. Lupton stressed that, when looking at weight
gain and obesity, the rest of the diet is as important as the type of
carbohydrate, if not more so. This comes back to the issue of
carbohydrate to fat to protein ratio, which will be addressed by the
new subcommittee on macronutrients.
Dr. Lupton shifted the focus of her presentation
to the ultimate goal of the Subcommittee's work, which is to determine
whether the existing Dietary Guidelines need to be modified.
She noted that half of the existing Dietary Guidelines could be
affected by the Subcommittee's decisions regarding carbohydrates.
These include:
- Aim for a healthy weight,
- Let the Pyramid guide your food choices,
- Choose a variety of grains daily, especially, whole grains,
- Choose a variety of fruits and vegetables daily, and
- Choose beverages and foods to moderate your intake of sugars.
Dr. Lupton then provided an overview of the
Subcommittee's literature search in Category 1, which was the
relationship of carbohydrate intake to obesity. To research the first
question in this category (the relationship of carbohydrate intake to
obesity), the Subcommittee searched Medline from 1999 to the present
(1999 was the cut-off from the previous Dietary Guidelines
report). The search excluded upfront animal in-vitro studies and
review articles. The search produced 94 articles, of which 27 were
retained. After reading the articles, 24 were retained. Articles were
not retained if carbohydrates were not the intervention.
Nine of the articles that were retained involved
carbohydrate to protein to fat ratio and weight loss. The new
subcommittee on macronutrients will deal with those. The remaining
articles were divided into two categories: specific carbohydrate
interventions; and high glycemic versus low glycemic carbohydrate,
intake and satiety factors.
With respect to the issue of carbohydrate intake
and obesity, Dr. Lupton asked the Committee to comment on whether the
Subcommittee should base its conclusions on type of carbohydrate, and
whether it had specified the right categories for type of
carbohydrates. She also asked for input as to whether the Subcommittee
should focus exclusively on the final outcome, or BMI, or if it should
look at intermediate endpoints, such as satiety, insulin response, or
post-prandial blood glucose concentrations. She noted that these are
two different literature bases.
The second research question in Category 1 was
whether there is a measurable difference to human health between whole
grain consumption and refined grain consumption. The literature search
found 81 abstracts pertaining to whole grains and human health, of
which 67 were retained as being relevant to this topic. Dr. Lupton was
pleased to find that the abstracts they retained were the same ones
that Dr. Slavin had cited in her presentation. The Subcommittee is in
the process of reviewing these studies.
Dr. Lupton asked the full Committee whether whole
grains should be the driving force of a carbohydrate recommendation
for the Dietary Guidelines if the review of the literature
confirms that whole grains have a significant beneficial effect on
human health. Alternatively, should the Subcommittee attempt to
determine how much of the health benefits are due to the whole grain
itself, and how much are due to its fiber content? Dr. Lupton noted
that fiber is the major component that is lost when grain is refined
and is not present in enriched grain products. As a result, many would
argue that fiber is responsible for the benefits of whole grain. Dr.
Lupton also asked whether recommending whole grain as a proxy for
fiber would place too great an emphasis on grain products at the
expense of other fiber sources such as fruits, vegetables, and
legumes.
Dr. Lupton returned to the subject of added
sugars because it was a complicated issue. The Subcommittee had two
research questions in this area. The first was whether it is possible
to quantify the level at which added sugar consumption might
negatively impact human health. Dr. Lupton noted that there might be
more than one mechanism involved, each of which would need to be
investigated. One hypothesis is that sugar in the diet can lead to a
dilution of micronutrients among people who reduce their intake of
other foods to compensate for the extra calories in the sugar. Another
possible outcome of added sugar could be weight gain among those who
consume the sugars on top of their normal diets. These are two
separate literature bases. Another issue that the Subcommittee
proposed to research was the relationship of fructose to human health.
Dr. Lupton noted that the issue of added sugars
was covered extensively in the IOM Macronutrient Report, which
recommended that added sugar should be no more than 25 percent of
total calories. The recommendation was based on added sugar intake
data that was combined with nutrient intake data. She presented a
table from the Macronutrient Report showing that, in general, as added
sugar intake goes up, the intake of micronutrients goes down. At 25
percent of added sugar intake, there was a depression in the intake of
specific micronutrients. Dr. Lupton stated that while the Food and
Agriculture Organization/World Health Organization stated that the
level should be lower than 25 percent, she was unaware of any
arguments for increasing the limit.
To complicate matters further, Dr. Lupton cited a
recently published study that suggested the outcome can vary depending
on the food to which the sugars are added. Added sugars in sweetened
dairy products were positively associated with calcium intakes, and
added sugars in breakfast cereals increased the likelihood of children
and adolescents to meet the recommendations for calcium, folate, iron,
and dairy products. On the other hand, added sugars in sweetened
beverages, sugars and sweets, and sweetened grains decreased the
likelihood of meeting the DRIs for calcium, folate and iron. And, the
only children whose mean calcium intake met the AI were those who did
not consume sugar-sweetened beverages.
Dr. Lupton raised the question of whether it is
possible to meet 100 percent of the DRIs for all nutrients without
exceeding recommended energy intake levels. After reviewing the
proposed food patterns, she discovered that the maximum amount of
discretionary calories after meeting the DRIs for all nutrients would
be 13 percent of intake and that level would only be valid for those
at the highest end of the scale (active males, with proposed intake of
3,200 K-cals). Those at the lowest end of the scale (sedentary adult
males and females, children from ages four to eight, females aged 51
to 70, and adults over age 70, with proposed intake of 1,200 to 1,600
K-cals) would have only six percent of their calories available for
discretionary intake, including added sugars. Given that information,
Dr. Lupton asked whether the ability to meet 100 percent of the DRIs
at a specific energy intake level is a justifiable and reasonable
approach. Should the concept of nutrient density be considered instead
of specifying added sugars? Would it be preferable to talk about
discretionary calories that could be used in a variety of ways, to
stress the need for nutrient density?
Dr. Lupton turned to the fourth category of
questions the relationship of carbohydrate intake to diabetes and
heart disease. She stated that the IOM Macronutrient Committee found
that there was very little literature on the role of carbohydrates,
per se. The Macronutrient Committee also concluded that there was
insufficient evidence on which to base a recommendation regarding the
glycemic response. With regard to heart disease, the only carbohydrate
included in the Macronutrient Report was fiber. The report includes a
number of tables on the relationship of dietary fiber to heart
disease. Dr. Lupton noted that, for the first time, there is now an AI
for dietary fiber. She asked the Committee if it agreed with the
recommendations from the Macronutrient Report in this area.
The fifth category was the overall significance
of fiber in the diet. Dr. Lupton noted that the Subcommittee's
research questions in this area and many others could be answered by
the Macronutrient Report. As such, these questions would fall into
category "A." She asked the full Committee if there were any specific
questions on fiber that need to be answered that were not covered by
the Macronutrient Report? Most importantly, she asked if fiber intake
should form the basis of the food related recommendations, or if the
Dietary Guidelines should recommend a particular food source
for fiber.
Dr. Lupton opened the floor to discussion, noting
that she would repeat the Subcommittee's questions for the full
Committee in the order that she had just presented them. She began by
asking for the Committee's comments on the relationship of
carbohydrate to weight.
Discussion
Dr. Pate noted that the Committee had decided to
emphasize prevention of weight gain rather than weight loss, per se.
He asked Dr. Lupton if the Subcommittee had reviewed any
epidemiological studies. Dr. Lupton noted that they had only found one
such study, but that they might find others when they do subsequent
searches by type of carbohydrate.
The Committee concurred with Dr. Lupton that
glycemic index should not be reviewed further. Dr. Kris-Etherton
suggested that it might be worth looking at the literature on glycemic
response if time allowed. Dr. King noted, and others agreed, that
glycemic response and other intermediate endpoints might vary with
BMI. Committee members suggested that the Subcommittee review the
literature for both normal and overweight individuals to determine if
certain associations were limited to people who are sedentary or
overweight. It was noted that it might be difficult to construct a
summary table about intermediate endpoints such as satiety, insulin
resistance, response, or post-prandial glucose, since well-accepted
clinical outcomes in these areas are lacking.
Committee members noted that foods such as
fruits, vegetables, and legumes should be added to the list of types
of carbohydrates for the purposes of the literature review. Dr. Lupton
expressed concern that more subcategories would result in fewer
studies, which in turn would weaken the evidence base for
recommendations.
Dr. Caballero noted that it would be important to
acknowledge that millions of Americans appear to be listening to a
number of prominent nutrition experts who have gone on record blaming
the increase in obesity in the United States on the recommendation to
reduce fat intake. It will be important to have a very solid evidence
base because the Dietary Guidelines will have to address that
issue one way or the other.
Dr. Pate asked whether there was any literature
that addressed specifically sugar beverage intake and weight or
obesity issues. Dr. Lupton deferred discussion of that question. She
then asked for the Committee's input as to whether whole grains should
be the driving force behind a carbohydrate recommendation.
Dr. Weaver supported a flexible approach that
would allow individuals to choose foods to meet fiber needs. Dr.
Clydesdale raised a concern about addressing the need to improve food
labeling regarding whole grains, which might entail changing some of
the laws. There was general agreement among Committee members that
fiber should be considered the primary factor in the health benefits
of whole grains. Dr. Weaver noted that the food patterns include
grains partly because of their contribution of micronutrients, as well
as fiber.
With regard to the issue of added sugar, there
was general discussion but no consensus about whether it would be
possible to justify aiming for 100 percent of DRIs at each energy
level. The Committee noted that many variables were involved,
including the amount of fat and protein in the diet. The importance of
flexibility was stressed once again.
Dr. Pate raised the issue of added sugars in
beverages, which is a food item that is understood very well by the
public. Dr. Lupton replied that the Subcommittee would present the
result of their review in this area at the next meeting. Dr. Caballero
stated that it might be important to ask Barbara Rolls to comment on
whether the ability to regulate and compensate for liquid calories is
different than solid calories. Dr. Lupton agreed that discussion of
this topic should be deferred until the facts were available. She
noted that the question of whether nutrient density should be
considered instead of specifying particular foods, like added sugars
or added fats, was emerging as an overarching issue.
Dr. Lupton turned to the issue of the
relationship of overall carbohydrates to disease. She noted that the
relationship between fiber and coronary heart disease was a
well-documented endpoint and asked whether the Committee supported
accepting the DRI recommendation for fiber. Dr. Nicklas suggested
looking at a range of fiber intake, particularly for younger children,
to see how that affects the food patterns. She noted that decreasing
the number of servings from legumes would provide additional
flexibility regarding sources of fiber. Dr. Lupton noted that the DRI
report did contain transition recommendations for fiber in children.
In response to a question from Dr. King, Dr.
Lupton confirmed that the IOM Macronutrient Committee had developed
the range of recommended fiber intake by assuming 14 grams of fiber
per 1,000 K-cal intake. Those at the higher end of the calorie intake
have a higher requirement for fiber because they are eating more
calories. Dr. Nicklas asked if recommendations took into account the
diminished capacity of the elderly to absorb vitamins and minerals.
Dr. Lupton replied that fiber levels for the elderly were lower
because their calorie needs were lower. The IOM Committee determined
that there should not be an upper level of intake for fiber,
especially in light of laxation concerns among older people. She noted
that mineral balance studies with fiber were no longer being
conducted, so there would be no additional evidence in that area.
Dr.
Lupton thanked the Committee for their input and turned the floor over
to Dr. King. Dr. King congratulated the Subcommittee for an excellent
piece of work and for clarifying all of the issues that need to be
addressed under the general area of carbohydrate. She noted that the
presentations on fatty acids and carbohydrates underscored the need
for a macronutrient subcommittee. She asked Dr. Lupton and Dr. Kris-Etherton
to serve on that subcommittee, along with Dr. Pi-Sunyer, Dr.
Caballero, and Dr. Weaver.
Additional Areas for Further Discussion
Dr. King called the Committee's attention to a
list of additional areas for further discussion, and that the list had
been compiled after reviewing the 2000 Dietary Guidelines in
order to help in the transition from nutrient-based analysis to
food-based recommendations. The following Subcommittees agreed to
address each issue:
- The proportion of cereals that should be whole grains
(Nutrient Adequacy, Carbohydrates)
- The number of servings as fruits and vegetables
(Nutrient Adequacy, Energy, Carbohydrates)
- Guidance about the intake of added sugars (Carbohydrate,
Energy; possibly Nutrient Adequacy)
- Choose and prepare foods with less salt (Fluid and
Electrolytes)
- Guidance on amounts of fats, types of fats, and
cholesterol (Fatty Acids, Macronutrients)
- Guidance about alcohol intake (Ethanol, Energy; possibly
Macronutrients)
Dr. King
proposed waiting until after the presentations from the remaining
Subcommittees before determining which ones would address issues
related to dairy foods, nutrient density, nuts and legumes, and the
foundation of the diet.
(Lunch: 12:00-1:10)
Nutrient Adequacy Presentation and Discussion
C. Weaver, Lead
Dr. Weaver noted that she had been working with
Dr. Nicklas, Dr. Bronner, and Dr. Go. The Subcommittee chose to adopt
the DRIs as a standard and the proposed food patterns in the
Federal Register developed by USDA staff as a starting point.
The Subcommittee's priority issues for research
were to determine whether there were any nutrients for which the DRI
set a requirement that were not met by the food patterns, and how much
flexibility was available in the patterns to accommodate special
needs.
The Subcommittee identified three priority
research issues:
- The proposed Food Guide Pyramid patterns did not meet vitamin E
recommendations from the DRI. Can we make dietary suggestions for
meeting the requirements? Is the evidence sufficiently strong to merit
recommendations that ensure meeting the RDA?
- How much flexibility is there is meeting nutrient adequacy of the diet
by specifying minimal servings of a specific food or group of foods?
- Are there special considerations for meeting nutrient needs throughout
the lifecycle beyond the DRIs, especially for the elderly?
The Subcommittee classified the first question as
level "A" because of the IOM Report that relates vitamin E and disease
and discusses how the RDA was set. The second and third questions were
classified as level "C," as it was not possible to develop summary
tables and the Subcommittee required input from outside experts.
To address the first question, the Subcommittee
asked vitamin E researcher, Dr. Maret Traber, who served on the IOM
Panel that developed the RDAs for vitamin E to provide them research
for their consideration. They asked her to address a number of
questions: What advice would you give consumers on how to meet the new
vitamin E requirements? Are there different recommendations for
different populations? How strong is the scientific evidence on the
effects of vitamin E on the prevention of chronic disease? Is there a
particular form of vitamin E other than alpha-tocopherol that may be
beneficial? And, how accurate are the alpha-tocopherol values in the
national nutrient databases?
One example for meeting the vitamin E
recommendations through foods was to consume one ounce of almonds,
plus one ounce of sunflower seeds, plus two tablespoons of peanut
butter daily. The Subcommittee found this to be far too prescriptive
and asked the staff to identify food sources of vitamin E, including
the vitamin E concentration per serving and the contribution of that
category of that food in the typical American diet. It was found that
foods that were high in vitamin E were not often consumed in
significant amounts. It would be important to consider consumption
patterns when making recommendations.
With regard to health, there is a study that
showed increased consumption of nuts led to increases in
alpha-tocopherol blood plasma levels, suggesting it might be
reasonable to advocate that including nuts in your diet as a rich
source of vitamin E has this health effect.
Dr. Weaver stated that, according to the DRI
Report, there is very little evidence suggesting that vitamin E plays
a role in the prevention of chronic disease. The Subcommittee
determined that the study that was used as the basis for the RDA was
not worthy of extraordinary measures to recommend getting 100 percent
of the RDA. Dr. Weaver noted that since the IOM Report was issued, the
HOPE Trial came out stating that there was no harm or benefit in
all-cause mortality associated with supplementing the diet with
vitamin E.
The Subcommittee was
also interested in vitamin E bioavailability with fortified
foods or supplements. A recent study on fortified cereals showed that
fortified cereals raised plasma vitamin E levels. One explanation may
be because vitamin E is on the surface of the food and therefore
absorbed quite readily. Some research indicates that bioavailability
can be compromised on a low-fat diet.
The form of vitamin E appears to be important.
The RDA is based on alpha-tocopherol, because it is the only form that
has been shown to reverse vitamin E deficiency symptoms. There is
insufficient evidence that gamma-tocopherol can be a substitute.
Dr. Weaver noted that it is difficult to estimate
the vitamin E intakes of the population. Food composition databases
remain a barrier, but capturing accurate survey data on what people
eat, especially amount and type of fat, is an even greater weakness.
The Subcommittee's conclusion at this point with
regard to a vitamin E requirement is not to alter the proposed Food
Guide Pyramid patterns in an attempt to specifically meet the RDA for
vitamin E. However, the text should point out sources of vitamin E so
that consumers could try to increase their intake. Dr. Weaver noted
that the proposed Food Guide Pyramid patterns are moving toward
improved vitamin E intake.
Dr. Weaver then addressed the issue of how to
make recommendations for food choices as flexible as possible and
still meet nearly 100 percent of the RDAs for the different nutrients,
aside from vitamin E. To date, the Subcommittee has focused on the
grains and cereals group. All of the twelve food patterns recommend
that half of the servings in this group should be whole grains. The
Subcommittee asked whether nutritional adequacy would be compromised
if enriched grains were omitted from the diet. An analysis conducted
by USDA showed that some patterns would have shortfalls in folate,
calcium, magnesium, iron, and fiber.
USDA helped the Subcommittee identify two
strategies to achieve 100% of the nutrients in that category. The
first was to replace enriched grains serving-for-serving with whole
grains. The second was to replace each serving of enriched grains with
dark green vegetables and legumes (one cup of each per serving of
enriched grains on an 1,800 calorie food pattern).
Dr. Weaver reminded the Committee that the goal
of the food patterns was to meet the nutrient requirements and
appropriate energy balance with the fewest changes from the typical or
current American eating habits. She referred to Dr. Hentges'
presentation on the first day, which showed that the proposed food
patterns were already asking Americans to make dramatic changes in
their intake of certain types of foods compared to what they are
currently consuming. She asked the Committee to keep that in mind
before proposing any additional "what if" scenarios.
Dr. Weaver noted that it would be possible to
offer further flexibility for individuals' eating preferences.
Interactive educational tools would be helpful in that regard.
The Subcommittee discussed placing soft margarine
with solid fats, rather than with oils, because of their trans
fat content. They felt this was an overarching issue and deferred
discussion on that question.
Dr. Weaver noted that the Subcommittee had
discussed a unique position for legumes, seeds, and nuts. In the end,
they decided against that, because removing them from the Meat group
would leave no plant-based alternatives in that group, while removing
them from the Vegetable group could send a message to consume fewer
vegetables.
The Subcommittee invited Dr. Johnson to address
the nutritional needs of the elderly. Dr. Weaver stated that the
Subcommittee would consider several of Dr. Johnson's suggestions,
including supplementation for vitamin B-12 for that group, and would
have further discussions regarding vitamin D.
Dr. Weaver noted that Dr. Bronner had asked the
Subcommittee to address the role of dairy products in youth, not only
for building peak bone mass but for offsetting or reducing risk of
osteoporosis and chronic diseases later in life. Dr. Weaver stated
that the Subcommittee would address that question.
Dr. Weaver asked the Committee whether there were
any other questions about flexibility of food groups, or emphasis on
food groups to meet nutrient recommendations that the Subcommittee
should consider. She stated that her Subcommittee was particularly
interested in the nutrient density aspect of that question, and she
noted that USDA staff had prepared an analysis of the nutrients by
food group in one food pattern. Dr. Weaver felt this was an important
first-step in addressing the issue of nutrient density. It also paved
the way for designing interactive tools for consumer use. For example,
if a person disliked the deep yellow vegetables that provide 40
percent of their vitamin A, the computer could provide additional
choices for obtaining that nutrient.
Dr. Weaver opened the floor for discussion.
Discussion
Dr. Clydesdale asked whether the discussion about
replacing enriched grains also involved fortified whole grains. Dr.
Weaver replied that some fortified foods were included, but others
were not.
Dr. King asked Dr. Weaver to clarify the
Subcommittee's proposal that it would be acceptable to recommend food
patterns that do not meet the RDA for vitamin E. Dr. Weaver stated
that the lowest amount of vitamin E in the proposed food patterns is
50 percent. The Subcommittee felt the evidence did not support making
a stronger recommendation, other than to provide a list of good
sources of vitamin E in the text. Dr. Appel cautioned that the
Committee would have to defend very carefully a recommendation to meet
only half of the RDA, even if the RDA was based on a bad study.
Dr. Lupton asked if this would be the only
instance where the Committee would go against the DRIs. She noted that
the best way to phrase it might be to say that we acknowledge the DRI,
but it is not easy to meet that level through food choices. In that
case, the Committee could go as low as 50 percent and provide the
evidence that this would not be harmful. Dr. King concurred, and she
added that it would be important to include information on how to meet
the vitamin E RDA so that if individuals chose to go that way, they
would know how to do so.
The discussion returned to the issue of whether
the food patterns need to meet 100 percent of the RDA. Dr. King noted
the RDA is set to meet the nutrient requirements of 97.5 percent of
the population. She asked whether the Committee should be using the
RDAs, or if it should be using the EAR, which meets the needs of 50
percent of the population. Dr. Lupton pointed out that there is no EAR
for nutrients that have AI levels, and she asked what comparable
number would be used use for nutrients that do not have an RDA.
Dr. Pate noted that an attempt was made in the
food patterns to adjust for activity level and asked if the
Subcommittee's considerations were based on the sedentary food
patterns. Dr. Weaver replied that they had looked at all twelve
proposed patterns. A discussion ensued regarding what level would be
used for the Dietary Guidelines. There was a secondary
discussion about how to reconcile the descriptive terms for levels of
physical activity in the CDC report and the DRIs. Dr. Weaver expressed
concern that specifying one pattern would remove much of the
flexibility that exists when there are twelve patterns. The current
Pyramid expresses this flexibility by providing a range of servings
within each food group.
Dr. King stated that the Food Guide Pyramid
incorporates two very important things in diets and nutrition. One is
the pattern of the food groups, and the second is the quantity within
the food groups. She stated that the Committee appeared to be
struggling with how to integrate those two things, because quantity is
directly tied to energy needs, and the pattern is related to nutrient
adequacy. She asked Dr. Hentges if USDA had ever envisioned a graphic
that would deal with nutrient adequacy by showing people what food
groups they need to include in their diets every day, with some
non-quantitative, but qualitative information on amounts, possibly
with different levels of energy intake as a sub-graphics.
Dr. Hentges replied that this would be part of
the consumer testing, but the technical, science-based parameters for
the guidance would need to be developed before they could adequately
develop the messages and graphic imaging to convey that guidance.
A lengthy discussion ensued. Dr. Pate stated that
it seemed the most consistent to target both the activity and the
dietary recommendations at the same healthy lifestyle. Dr. Nicklas
stated that it would be important to consider how to incorporate needs
for different age groups when selecting physical activity and energy
levels.
Dr. Bronner stated that it was her understanding
that the Committee agreed that no one table would fit the lifecycle
and reflect the complexity of the population. Rather, it would develop
one model around which many of the messages could be communicated, and
individuals could customize this model based on their activity level
and energy needs.
Dr. King asked if the Subcommittee was looking at
several different patterns to address nutrient adequacy, independent
of energy needs. Dr. Weaver replied that they were working with all 12
patterns simultaneously. Any proposed iterations were done across all
12 patterns. In coming weeks, the Subcommittee would be examining the
issue of nutrient density by looking at the contribution of different
foods within the 12 patterns, nutrient-by-nutrient, in order to be
able to generate information regarding flexibility of food choices.
Dr. King asked Dr. Weaver whether she thought the
relationship of dairy food intake and bone health in the young and the
risk of osteoporosis later in life was an issue that needed to be
addressed. Dr. Bronner stated that this question had come out of her
thinking about how to communicate messages around nutrient needs at
different points in the lifecycle. One of the clearest examples of
that was calcium. Calcium intake is crucial for building bone in the
early years, and then is protective of disease, disability, and health
care costs at a later point in life. Dr. Bronner would be reviewing
the evidence and would present her findings at the next meeting. The
Committee concurred that this would be an important message to
include.
Summarizing the discussion, Dr. King stated that
the Subcommittee would not have to go back and try to meet the vitamin
E RDA, but the rationale for that decision would have to be developed
carefully. The Subcommittee would review food patterns at different
levels of fat, looking at different combinations that promote nutrient
density. Finally, the Subcommittee would review the literature with
regard to dairy food consumption, bone health, and risk of
osteoporosis, and incorporating this into the activity patterns.
Dr. Nicklas added two additional items. The
Subcommittee would look at fiber ranges at the younger ages and see
how that alters the food patterns. The Subcommittee would also look at
different subgroups of fruits and vegetables and see how that alters
the patterns, and it would also look to see if it might be necessary
to make separate recommendations for fruits as a whole versus fruits
and juices.
Dr. Bronner stated that she would not need to
make a separate presentation, since the Nutrient Adequacy Subcommittee
would now be addressing lifecycle issues.
Dr. King
turned the floor over to Dr. Clydesdale and the Food Safety
Subcommittee.
Food Safety Presentation and Discussion
F. Clydesdale, Lead
Dr. Clydesdale stated that his colleagues on this
Subcommittee were Dr. Camargo and Dr. Weaver and thanked the staff for
their support. He noted that his presentation would consist of a
review of what the experts had said, plans for future investigations,
recommendations to date, and possible future recommendations.
The Food Safety Subcommittee had three level "B" research questions. The first question, and also the Subcommittee's
top priority, was: What acts or activities are most likely to cause
food safety problems, such as food borne illness? And try to
prioritize these acts. The Subcommittee wanted to make sure that these
activities would be addressed in the recommendations in the
appropriate detail and the appropriate manner. The Subcommittee met
via conference call with several experts, because there was no
comprehensive table already developed in the scientific literature or
otherwise.
The second question was: What data are there
regarding effectiveness of hand washing, including use of bacterial
cleansers in preventing food borne illness? The Subcommittee's third
research question was: How do people view the recommendations on food
safety and do they change their behavior? What makes them change their
behavior? Dr. Clydesdale stated that the Subcommittee had reviewed the
data on questions one and two. Question three was addressed to some
extent by one of the scientific speakers, but the Subcommittee is
still investigating this area.
To address the first research question, the
Subcommittee consulted with Dr. Mike Doyle from the University of
Georgia; Dr. Lydia Medeiros from Ohio State University; and Dr. Isabel
Walls from the International Life Sciences Institute, Risk Science
Institute.
Dr. Doyle ranked ordered the activities as:
improper hand washing; failing to keep foods cool at proper
temperatures; failing to avoid cross-contamination; and inadequate
cooking. He referred the Subcommittee to a 1988 paper, which he said
reviewed the literature fairly well in this area. That paper included
the same activities, with improper cooling ranked as the major cause
of food borne illness, followed by improper hand washing.
Dr. Clydesdale stated that the advice to clean,
separate, cook, and chill which is the "Fight Bac!" message, is still
applicable and critical for consumers. The Subcommittee would
recommend keeping that message, with the addition of another chill
step before cooking. The revised advice would be to clean, separate,
chill, cook, and chill. He stressed that consumers need to be told in
exquisite detail exactly what to do.
A paper by one of the Subcommittee's other
consultants, Dr. Medeiros, emphasized the primary importance of using
a thermometer to cook foods thoroughly. (Dr. Clydesdale noted that the
Subcommittee would like to retain the thermometer graphic that appears
in the current Dietary Guidelines.) That paper also listed hand
washing, avoidance of cross-contamination, and avoidance of certain
foods likely to be contaminated as important actions to prevent food
borne illness. In another paper that focused on consumer education,
Dr. Medeiros cited hand washing, adequate cooking, and avoiding
cross-contamination as the three primary messages, with secondary
messages of keep food safe to eat, and avoid foods from unsafe
sources.
The Subcommittee's plans for future investigation
are to expand its discussion of high-risk categories; to determine
methods and recommendations for cleaning fresh fruits and vegetables;
and to continue its evaluation of mechanisms for behavior change.
Dr. Clydesdale listed the high-risk groups as "the three Ps": people (special needs groups); pathogens (listeria and
others); and products, especially ready-to-eat products. The special
needs groups identified in the current Dietary Guidelines are
pregnant women; young children; older persons; and people with
weakened immune systems or certain chronic illnesses. The Subcommittee
is looking at others, including people with diabetes, people on
steroids, and people with chronic suppression of gastric acids and
immune compromise. The Subcommittee will ask the full panel to comment
on whether these should be included in the Dietary Guidelines.
Dr. Clydesdale presented data from a paper by Dr.
Medeiros and others that showed the food handling behaviors and
specific pathogens of importance to pregnant women, infants, and young
children. He noted that listeria is a major pathogen in ready-to-eat
products. While the normal healthy population appears to be at very
low risk for listeria, there is a very high mortality rate among those
in high-risk groups. Dr. Clydesdale emphasized the importance of
letting consumers know that there are certain foods they should avoid
under certain situations.
Dr. Clydesdale noted that there have been recent
outbreaks of food borne infections from fresh produce. The
Subcommittee prepared a list of proper procedures for cleaning various
types of fruits and vegetables and would continue to review the
literature, particularly with regard to root tubers and fragile
fruits. The Subcommittee would like to include detailed instructions
in the Guidelines.
Dr. Clydesdale reported that the Subcommittee
would make a quantitative recommendation on hand washing with soap and
water; it would expand the advice on cleaning refrigerators and
counter-tops to avoid cross-contamination and the risk of pathogens;
it would keep the "Fight Bac!" message, with the addition of a second
chill step; and it is considering the methylmercury fish
recommendation. The Subcommittee would also expand the advice about
throwing out unsafe food.
The Subcommittee conducted a literature review
and prepared summary tables on hand washing. The findings included: 1)
Alcohols have very poor activity against bacterial spores; 2)
Ingredients used in hand-based gels for retailer food service must be
approved for food additives; and 3) Retail and food service work
involves high potential for wet hands contaminated with proteinaceous
material, but the research questions the efficacy of alcohol on moist
hands and hands contaminated with proteinaceous material.
The FDA and CDC both recommend washing hands with
soap and water, when it comes to food handling. The CDC recommends
washing for 15 to 20 seconds, or long enough to sing the "Happy
Birthday" song twice. The Subcommittee proposes to include detailed handwashing instructions in the Dietary Guidelines.
The rationale for keeping the "Fight Bac!" message is the fact that awareness of any campaign about safe food
handling was up to 46 percent in 1999, versus 39 percent in 1997 when
the Partnership for Food Safety Education started. And surveys of
consumers in two cities where a concentrated "Fight Bac!" education
effort took place showed a higher awareness of general food safety
principles, when compared to national averages. The literature also
showed large improvements in consumer food safety practices between
1993 and 1998, and a 2001 survey found that these gains were
maintained or improved.
With regard to methylmercury, Dr. Clydesdale
noted that the FDA Food Advisory Committee recently recommended
maintaining current dietary advice. The FDA's dietary advice
specifically states that fish and shellfish can be an important part
of a healthy diet. In the absence of sufficient information on the
forms of methylmercury in each species of fish, the Subcommittee would
go along with the FDA Food Advisory Committee's recommendation and
would not propose any new messages in this area.
Dr. Clydesdale opened the floor for discussion.
Discussion
Dr. Kris-Etherton asked if the Subcommittee would be dealing with
issues such as PCBs in fish, hoof-and-mouth disease, and mad cow
disease that are hot buttons for consumers. Dr. Clydesdale replied
that while the Subcommittee acknowledged the level of public concern,
it felt that it would be more important to emphasize the big risks
that they can do something about than to fill them with fear about
things that are much smaller risks.
In response to questions from Dr. Appel, Dr. Clydesdale stated that
the Subcommittee would prepare detailed information on how to avoid
contamination in specific foods, including deli meats. He emphasized
that the Subcommittee does not want its recommendations to have the
unintended consequences of eliminating foods that are convenient for
people to eat.
Dr. King congratulated the Subcommittee on its work to date. She
informed the Committee that at the end of the day she would like to
have each of the Subcommittee leads give a mini-report of what key
conclusions they had come to as a result of the day's discussions,
what conclusive statements and rationale they would be able to give to
Dr. Suitor in early February to start drafting the report, and what
key things they would be working on between now and the March meeting.
(Break; 2:30-2:45)
Ethanol Presentation and Discussion
C. Camargo, Lead
The Ethanol Subcommittee consisted of Dr.
Camargo, Dr. Kris-Etherton, and Dr. Appel. Dr. Camargo prefaced his
presentation by acknowledging that alcohol is a contentious issue and
people have strong feelings about it. He then provided an overview of
the relevant advice in the 2000 Dietary Guidelines, which were
the starting point for the Subcommittee's work.
The ethanol recommendation in the 2000 Dietary
Guidelines was, "If you drink alcoholic beverages, do so in
moderation." There were three supporting statements for this
recommendation: Alcoholic beverages supply calories, but few
nutrients. Alcoholic beverages are harmful when consumed in excess,
and some people should not drink at all. If adults choose to drink
alcoholic beverages, they should consume them only in moderation, and
with meals to slow absorption.
"Moderation" was defined in the 2000 Dietary
Guidelines as no more than two drinks per day for men, and no more
than one drink per day for women. The Dietary Guidelines stated
that drinking in moderation may lower risk for coronary heart disease,
but mainly among men over age 45, and women over age 55. And another
highlight of the last iteration was the statement that even one drink
per day can slightly raise the risk of breast cancer.
The Subcommittee felt that the advice in the 2000
Dietary Guidelines was accurate and did not require
modification. Through their discussions, the Subcommittee identified
several new issues. Dr. Camargo thanked HHS, USDA, and the National
Institute on Alcohol Abuse and Alcoholism (NIAAA) for assistance. He
stated that the NIAAA's State of the Science Report was an excellent
document that summarized the last few years of literature. Dr. Camargo
noted that, in many respects, the NIAAA report supports leaving the
guideline largely intact because the latest data has largely confirmed
what was known at that time.
The first additional issue that the Subcommittee
discussed was the need to state clearly that abstention is an option
and to recognize that 35 percent of adult Americans do not drink
alcohol. The Subcommittee would propose adding this to the guideline.
The second issue was the possibility of lowering
the drinking limit for older men. The Subcommittee had data tables
drawn up so it could review the data to see whether the mortality
benefit was the same in older Americans. The data were largely
consistent with what is seen in other adults. After further research,
the Subcommittee determined that body composition arguments might
support lowering the drinking limit for older men to one drink per
day, though the evidence was not compelling. A discussion with experts
at NIAAA indicated that this may no longer be a critical issue because
as Americans are aging better, they are losing less lean body mass.
Dr. Camargo noted that the Subcommittee also
discussed racial and ethnic differences in alcohol metabolism. It was
the consensus of the group that these were not significant at the
moderate drinking level.
The Subcommittee felt that it would be important
to emphasize variability of calories from alcoholic beverages,
specifically noting that some alcoholic beverages, like dessert wines
or mixed drinks, can have almost three times as many calories as those
beverages are listed in the current Dietary Guidelines.
The Subcommittee also wanted to mention "designer drinks," which are
newer alcohol products that tend to target young adults and, possibly,
underage drinkers.
The Subcommittee thought that the discussion of
adverse impacts should be broadened. In particular, references to
"cirrhosis" should be changed to "liver damage," since lower levels of
alcohol intake can result in liver function abnormalities short of
cirrhosis.
The Subcommittee considered whether to change the
"drink with meals" advice to "drink with food." However, the foods
that are generally consumed with alcohol, apart from a meal, are
generally not the sort of snack foods that the Subcommittee wanted to
promote. They also reviewed compelling data showing how the quantity
and volume of a meal could slow the absorption of alcohol. As a
result, the Subcommittee proposed keeping the current language.
Dr. Camargo stated that the Subcommittee was in
the process of looking at associations between alcohol intake and a
variety of nutritional diet parameters, such as BMI, calories,
physical activity, macronutrients, micronutrients, and diet quality.
To date, they have prepared a data table on alcohol and BMI. As
expected, the literature was quite inconclusive. There was not a
strong association between consuming one or two drinks a day and
weight. With respect to macronutrients and micronutrients, the
Subcommittee's preliminary impression was that one to two drinks a day
would not be associated with any deficiency. With respect to diet, the
Subcommittee asked the USDA to do an analysis of some national
datasets looking at the Healthy Eating Index of people at different
levels of alcohol intake in the moderate range.
Dr. Camargo stated that he would favor putting
some comment about alcohol in the graphic of the Food Guide Pyramid.
He noted that the comment would need to specify that the advice be for
adults. Dr. Camargo requested input from the full Committee regarding
this question.
One area where the Subcommittee thought it might
change the current Guideline was to separate out some compelling,
temporary reasons to not drink alcohol, such as when planning to
drive, operate machinery, or take part in activities that require
attention, skill, or coordination. In the current Dietary
Guidelines, these are lumped together with larger reasons not to
drink, such as personal history of alcoholism or being underage.
The Subcommittee also recommended adding
breastfeeding to the list of temporary reasons to not drink. Dr.
Camargo emphasized that it would be important to dispel myths about
alcohol as a lactation aid. Recent data indicates that alcohol
consumption while breastfeeding has adverse effects on the infant's
feeding and behavior. Dr. Camargo suggested that the advice could also
state that if a breastfeeding woman does choose to drink in
moderation, she should do so after feeding her infant so that the
alcohol could be absorbed before the next feeding.
The Subcommittee recommended maintaining the
emphasis on the hazards of heavy drinking, but without specifying the
exact level of pattern of consumption.
The Subcommittee also proposed adding information
on why alcohol should not be consumed by adolescents, with an emphasis
on the risk of traumatic injury and death, which is the number one
cause of death in that age group. The animal data on the effect of
alcohol on brains could also help to illustrate why drinking is
inappropriate for adolescents. The Subcommittee also discussed the
fact that in some other cultures teenagers can drink and not have the
binge drinking experience that we have in this country. They concluded
that it would be beyond the scope of the Dietary Guidelines to
attempt to change the cultural milieu.
Dr. Camargo noted that there are some
demonstrated benefits of drinking. Studies conducted around the world
with different age groups including older adults consistently show
that alcohol can have a favorable impact on total mortality.
Dr. Camargo stated that there also continues to
be papers talking about beverage-specific effects. The Subcommittee
felt that while laboratory findings suggested that red wine might have
some extra health benefits, this finding did not translate into the
epidemiologic data. They found examples of populations who consumed
largely beer, and others who consumed largely distilled spirits
enjoyed the mortality reduction. Dr. Camargo thought that the primary
ingredient was ethanol. He opened that up to the larger group.
Dr. Camargo concluded his presentations with
several recommendations aimed at changing the culture around alcohol.
The first was to put a simple label on alcoholic beverages that shows
their caloric content (though not nutrients). The second
recommendation was to ban alcohol advertising when and where it might
encourage underage drinking. The final recommendation was to
consolidate authority about alcoholic beverages under one federal
agency.
Dr.
Camargo thanked the Committee and opened the floor to discussion.
Discussion
With regard to the issue of breastfeeding, Dr.
Weaver expressed concern that the concept of "safe timing" may be seen
as an endorsement for lactating women to drink. She also noted that it
would be unrealistic, given the difficulty of predicting when an
infant will want to feed. Dr. Camargo replied that the statement would
have to be worded carefully. While he agreed that the Subcommittee
should not endorse drinking for breastfeeding women, it should not
ignore the fact that many women believe that drinking can aid
lactation. He also stated that it would be unrealistic to expect women
to avoid drinking any alcohol during a one-year breastfeeding period.
He noted that the Subcommittee would retain the current Guideline for
pregnancy, which is zero tolerance. Dr. Bronner supported including
lactation in the literature review in order to see what the metabolic
process is.
Dr. Pate asked if the Subcommittee would
highlight DUI-related deaths and injuries to a greater extent than in
the previous Dietary Guidelines. Dr. Camargo replied that one
way to do that would be to list reasons why the group that is at
highest risk of traumatic injury i.e., adolescents should not drink.
Another way would be to go beyond the Dietary Guidelines to
target situations that lead to drinking-related deaths and injuries,
which could be suggested in the data section of the technical report.
Dr. King asked whether the liver disease that is
seen with high intakes of alcohol was a greater problem among obese
individuals who are also prone to fatty liver. Dr. Pi-Sunyer stated
that was not the case. Although people who have fatty livers tend to
be obese, these individuals generally do not drink much alcohol. Dr.
Camargo noted that one of the problems in this area is that many
studies in which moderate drinking is associated with a variety of
negative outcomes, actually define moderate drinking as three or more
drinks. The effects on the liver are minimal at the level defined in
the existing guideline, which clearly defines a maximum of one drink
per day for women and two drinks per day for men.
Dr. King asked the Committee to comment on the
possibility of including alcohol in the Food Guide Pyramid. Dr. Pi-Sunyer
was concerned that some consumers might understand this to mean that
alcohol consumption was recommended. Dr. Caballero noted that it would
make sense in a culture where wine was part of the typical dietary
pattern. Dr. Camargo stated that he understood those views, but he
also felt that including alcohol in the Pyramid would present an
opportunity to teach Americans about sensible drinking as they are
learning about nutrition. Dr. Kris-Etherton suggested that alcohol
could be included in the top of the Pyramid, along with added sugars
and added fats. Dr. Nicklas noted that if alcohol were included, there
would need to be a separate Pyramid for adults and children. Dr.
Clydesdale agreed that including alcohol in the Pyramid could give
adolescents more license to drink. Dr. Caballero noted that it would
be one of the only restrictive messages in the Pyramid, which on the
whole is designed to emphasize positive messages.
Dr. Lupton asked if the Subcommittee had
considered addressing the link between heavy drinking and impaired
judgment regarding sexual behavior, especially among younger people.
Dr. Camargo noted that the Subcommittee had, in fact, considered that
as another argument to try to discourage underage drinking. He noted
that this message could support efforts to prevent sexually
transmitted diseases and unwanted pregnancy, which are often
associated with underage drinking.
Dr. Caballero expressed concern about including
animal data in the report. While he did not question the evidence, he
thought this would be inconsistent with the rest of the Dietary
Guidelines, which generally did not quote animal data. Dr. Camargo
clarified that the animal studies would be included as supporting data
in the technical report and would not be quoted in the consumer guide.
He noted that animal studies had been used very effectively to promote
a zero-tolerance position for drinking during pregnancy.
Dr.
Pi-Sunyer asked if the alcohol recommendation should be modified for
older adults. Dr. Camargo replied that after reviewing the data, the
Subcommittee decided to maintain the existing guideline. This decision
was supported by the conclusions of the NIAAA report, which stated:
"Although elderly drinkers reach higher blood alcohol concentrations
(BACs) with lower levels of consumption than the younger counterparts,
their level of impairment at any given BAC level does not differ from
that of younger drinkers."
Fluid and Electrolytes Presentation and Discussion
L. Appel, Lead
Dr. Appel began his presentation by stating that
the Fluid and Electrolytes Subcommittee consisted of himself, Dr.
Caballero, Dr. Pate, and Dr. Weaver. Michael Sawka, U.S. Army Research
Institute of Environmental Medicine, served as a consultant on water,
and Kim Stitzel is the staff person for the committee.
Dr. Appel noted that he served as chair of IOM
Report on Fluid and Electrolytes, which looked at water, salt (sodium
chloride), potassium, and sulfate. The report had not been released as
of this meeting. He stated that the Subcommittee would only be dealing
with water, salt, and potassium; it would not address sulfate.
Dr. Appel stated that the Subcommittee had five
level "A" research questions related to sodium and potassium for which
evidence tables were available: What is the relationship between salt
intake and blood pressure? What is the relationship between salt
intake and cardiovascular disease? What is the relationship between
salt intake and osteoporosis? What is the relationship between
potassium intake and blood pressure? And, finally, what is the
relationship between potassium intake and cardiovascular disease,
parallel to the last three questions?
Dr. Appel noted that the Subcommittee would not
be in a position to discuss the level "A" questions until the IOM
report was released.
Dr. Appel reported that the Subcommittee was in
the process of conducting science-based reviews for two of its level
"B" questions: Does potassium intake modify the relationship between
salt intake and blood pressure (and vice versa)? And, what is the
relationship between potassium intake and osteoporosis?
The Subcommittee considered additional "B"
questions for which it probably will not do evidence-based reviews.
These were: Does race influence the relationship between salt intake
and blood pressure? Does race influence relationship between potassium
intake and blood pressure? Does calcium intake influence the
relationship between salt intake and blood pressure? And, does calcium
intake influence the relationship between potassium intake and blood
pressure?
Dr. Appel stated that the Subcommittee's major
discussion of these questions would occur at the March meeting.
Dr. Appel noted that none of the prior Dietary
Guidelines had dealt with what healthy Americans should do with
regard to consumption of water. The Subcommittee had extensive
discussions as to whether and how it should tackle this issue,
especially since the Committee needed some external expertise in this
area. The Subcommittee decided that there should be a guideline for
water consumption in the general population, given the highly
prevalent pattern of water consumption. The Subcommittee decided not
to cover the health effects of caffeinated beverages.
Dr.
Appel opened the floor for discussion.
Discussion
Dr. Camargo asked if the Subcommittee had
considered recommending that Americans should drink water with meals,
as opposed to sugar-laden beverages, which would make more calories
available for nutrient-dense foods. Dr. Appel stated that although the
Subcommittee had not considered that rationale for drinking water, it
would be a reasonable strategy for achieving energy balance.
Dr. Go asked if the Subcommittee had considered
the liquid content of fruits and vegetables, which is generally
between 50 to 80 percent. Dr. Appel stated that this was an excellent
point. He noted that while roughly 80 percent of total water
consumption comes from water in beverages, 20 percent comes from food,
including fruits and vegetables. Fruits, and particularly fruit
juices, are obviously important components of that 20 percent.
Dr. King asked if it would be important to
include water in the Food Guide Pyramid. Dr. Appel replied that the
Subcommittee did not have an answer to that question. Dr. Weaver noted
that the expert who was consulted by the Subcommittee did not
distinguish fluid water versus water from food. Dr. Caballero stated
that it would depend on whether the Subcommittee decided to make a
specific recommendation for water. There would be no reason to include
water in the Pyramid if it was not associated with a recommendation.
Dr. Caballero asked whether needs for
electrolytes and water remain relatively constant through various
levels of physical activity, except at the very high or competitive
level. Dr. Appel stated that the body seems to be able to
auto-regulate the amount of losses, at least in the range of exertion
that the Committee would be recommending. With high sodium and
potassium intakes, sweat losses of those electrolytes are high, while
sweat losses are greatly reduced at lower levels of intake. Dr. Pate
noted that sweat losses of water would probably be proportional to the
overall activity level. Dr. Appel and Dr. Pate both thought it would
be appropriate to ask the Subcommittee expert to address this
question.
Dr. Pate asked if there was any evidence that those who consume more
glasses of water per day displace other forms of beverage intake. Dr.
Caballero stated that the thirst mechanism is similar for sweetened
beverage or pure water. Dr. Appel noted that the addition of almost
any solute to water increases thirst, whether that solute is flavoring
or salt.
Dr. Nicklas asked if the Subcommittee had
considered whether magnesium played a role in blood pressure. Dr.
Appel replied that nutrients such as magnesium and calcium were
outside of the Subcommittee's charge. However, he noted that clinical
trials show no effect of magnesium on blood pressure. While magnesium
may have a small effect at high doses, he would not recommend it to
reduce blood pressure.
Dr. King asked if there was any health risk
associated with caffeinated beverages. Dr. Appel replied that the
findings of the observational studies with which he was familiar were
inconsistent. He stated that the caffeine literature was not strong
and that reviewing it would divert the Subcommittee's attention from
more important topics.
Dr. King thanked the Subcommittee for its
presentation.
Review of Meeting, Assignments, and Next Steps
J. King
Dr. King asked the Committee to return to the
list of additional areas for discussion that it had looked at briefly
before lunch and asked the members to determine which Subcommittees
would work on each question.
- Guidance on amount and type of dairy foods (Nutrient Adequacy)
- Nuts as a vehicle for the delivery of omega-3 fatty
acids (Nutrient Adequacy, Fatty Acid)
- Methods for developing the food guide patterns (USDA
staff)
Dr. King deferred discussion of the foundation of
the diet until some of the overarching issues were resolved. She then
asked each Subcommittee to identify: the conclusions it had reached
as a result of the discussions at this meeting; the statements it
could give to the writer by February 6; and a brief list of its next
steps.
Energy Balance
The Subcommittee would prepare statements
regarding the amount of physical activity to prevent excessive weight
gain and the amount of physical activity required to maintain weight,
with a goal of having them ready for the writer by February 6.
However, the Subcommittee would not have final concluding statements
regarding these questions until it heard from the CDC experts in
March. The Subcommittee might also have a statement on fruits and
vegetables and BMI by February 6.
The question of the carbohydrate to fat ratio
would be transferred to the new Macronutrient Subcommittee. Between
this meeting and March, the Subcommittee would work on the issues of
breakfast, energy density, the level of activity regulating appetite,
portion sizes, and leisure time physical activity modes.
Fatty Acids
This Subcommittee had some preliminary
conclusions. They would recommend a total fat level that is consistent
with the IOM AMDR for fat. They would recommend reducing saturated
fatty acids, trans fatty acids, and dietary cholesterol,
because they increase LDL.
The recommended level for unsaturated fats
required further discussion. The recommendation would depend in part
on the menu modeling exercises that USDA was preparing.
Before the next meeting, the Subcommittee would
look at the literature and develop recommendations for monounsaturated
fat and polyunsaturated fat, including omega-3s and omega-6s. They
would evaluate the fatty acid composition of fats and oils and
margarines, using existing food composition analyses. Additional
information from USDA and others would help determine how to
categorize solid fats and liquid fats.
The Subcommittee would conduct a literature
search on the impact of stearic acid on health outcomes and would
pursue the menu modeling exercise, looking at the impact on nutrient
adequacy of different fat levels, 20, 25, 30, and 35 percent. They
would also obtain information from NCI about fatty acids and cancer
risk.
Carbohydrates
The Subcommittee would soon provide the writer
with information on the efficacy of whole grains and human health. The
statement on whether fiber should drive the recommendations was close
to completion. They would also put together a glossary of the key
terms for carbohydrates.
The Subcommittee determined at this meeting that
glycemic index and glycemic load were not appropriate targets for
research.
The Subcommittee's next tasks would be to conduct
an expanded search for the effect of carbohydrates on weight, to
include grains, fruits, vegetables, milk, and so forth. The ratio of
carbohydrate to fat to protein, and its effect on weight management
would be a subject for the Macronutrient Subcommittee.
The questions pertaining to added sugars require
additional analysis. The Subcommittee would work on those issues with
the Nutrient Adequacy Subcommittee.
Nutrient Adequacy
The Subcommittee would recommend food patterns
where the goal is to meet the RDAs where possible, or AI where there
is not an RDA for nutrients and appropriate caloric needs. Although
the specific food patterns were still being developed, the
Subcommittee could state that their recommendations would call for
changes in the current eating patterns of Americans, including
increased green vegetable consumption, increased orange vegetables,
increased legumes, decreased starchy vegetables, increased whole
grains, decreased enriched grains, increased fruits, increased dairy,
decreased total fats, especially solids, decreased added sugars, and
decreased calories for many groups.
The Subcommittee would state that it is difficult
to meet the RDA for vitamin E.
The Subcommittee would recommend that half of the
grain servings in each food pattern category come from whole grains.
They would provide flexibility within this group by specifying
alternative sources for the nutrients currently provided by enriched
grains.
The Subcommittee decided not to recommend a
unique group for nuts, seeds, and legumes because that would leave no
plant food in the Meat group, it would have an unfavorable appearance
of recommending a decrease in vegetable consumption, and there is no
unique nutrient to those foods, although some may be recommended as
healthful choices.
Going forward, the Subcommittees would: 1) work
with USDA to generate tables of nutrient contributions for each of the
various food types for each of the patterns so that it could formulate
alternative strategies for any one individual nutrient; 2) review the
literature on the contribution of dairy and calcium and physical
activity in early life; 3) consider whether decreasing the
recommendation of fiber in the younger age group would alter the
ability to meet the DRI for other nutrients; 4) look at what
flexibility or specificity is needed within the fruits and juices
group; 5) make iterations to the food patterns to address special
needs identified at this meeting, such as individuals who do not eat
legumes, are lactose intolerant, or are vegetarians; 6) consider
supplements for the elderly with regard to B-12 and vitamin D, in
particular; and 7) look at the rest of the nutrient DRI achievement
after the iterations from the Fatty Acid Committee, looking at 25, 30,
and 35 percent of the calories as fat.
Food Safety
The Subcommittee would submit two recommendations
to the writer: keep the "Fight Bac!" message, with an additional "chill" step, and add a quantitative recommendation on hand washing.
The Subcommittee would also develop recommendations regarding the
at-risk populations and the at-risk foods. The
Subcommittee would recommend that the language regarding fish should
not be changed.
Going forward, the Subcommittee would look at the
steps for cleaning fruits and vegetables, including pre-packaged
salads, and it would continue to search the literature regarding
behavior changes.
Ethanol
The Subcommittee concluded that the 2000
guideline on alcohol recommendations are sound. It proposed to add
abstention as an option, to emphasize calories and the fact that they
can be highly variable, and to mention the diversity of alcohol
products without specifying brands.
The Subcommittee would separate out temporary
reasons not to drink, including before driving and use of heavy
machinery, and during pregnancy. It would add breastfeeding to that
category. The Subcommittee recognized that it would need to discuss
the wording to make sure that risk is minimalized.
The Subcommittee would expand the "no drinking"
list that is already in the Dietary Guidelines to include data
regarding hazards to adolescents. It would mention the animal study
data in the technical report. It would broaden the hazards by
expanding "cirrhosis" to "liver damage."
Going forward, the Subcommittee would review data
about alcohol and diet associations, including how alcohol at moderate
levels relates to macro- and micronutrients, and an analysis of how
moderate levels of intake relate to the Healthy Eating Index. It would
also work on the wording of a summary statement and consider different
ways to include alcohol in the recommendation for the Food Guide
Pyramid.
Fluid and Electrolytes
The Subcommittee's work is on hold until the IOM
report is issued.
Macronutrient
The members of the new Subcommittee include Dr.
Caballero, Dr. Kris-Etherton, Dr. Lupton, Dr. Pi-Sunyer, and Dr.
Weaver.
Closing Remarks
Dr. King noted that the Committee had
accomplished a great deal. She stated that it would be important that
the new Macronutrient Subcommittee meet fairly soon via conference
call. She thanked the Committee for making her job easy.
Dr. King adjourned the meeting at 4:15 p.m. 2005 Guidelines Page |