Zinc may have a key role in keeping cell
membranes intact, preliminary results of a new study suggest. This essential
nutrient may carry out that chore by functioning as an effective antioxidant,
safeguarding the membranes against damage caused by oxidative effects of other
minerals such as copper or iron. Cell membranes keep cell contents in place and
selectively allow salts or other compounds to flow in and out, as needed.
Scientists at the ARS Western Human Nutrition
Research Center, Davis, Calif., collaborated with investigators from the
University of Californias Berkeley and Davis campuses for the study. The
researchers worked with eight healthy men, age 27 to 47, who volunteered for
the 20-week experiment.
The volunteers ate typical foods at normal
mealtimes. For 10 weeks, they received only 4.6 mg of zinc, the amount
recommended by the United Nations World Health Organization. For a total
of another 10 weeks, the men received an additional 9.1 mg of zinc every day.
Laboratory tests indicated that study
participants red blood cell membranes were significantly more fragile
when measured after the 10-week low-zinc stint. This cell membrane change
occurred in the absence of any overt indicators of zinc deficiency, such as a
decline in their blood plasma zinc levels. The findings suggest that cell
membrane health may be a sensitive indicator of an individuals zinc
needs.
In addition, the findings emphasize the
importance of maintaining a good zinc intake. Foods that provide zinc include
beans, whole grains, shellfish, red meat, and dark-meat poultry.
For more information, contact
Janet C. King, (530) 752-5268,
USDA-ARS Western Human Nutrition Research
Center, Davis, CA
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Besides being fun to eat, watermelon is good
for you. Its a delicious source of lycopene--a health-promoting
phytonutrient.
Now, ARS researchers from Lane, Okla., and Beltsville,
Md., are looking into the influence of watermelon genetics on lycopene content.
Each of the 13 kinds of watermelon that the researchers analyzed had as much or
more lycopene as fresh tomatoes, which are considered a good source (Journal
of the Science of Food and Agriculture, 2001, vol. 81, no. 10, pp.
983-987).
A related study with 23 volunteers--healthy
men and women age 36 to 69--showed that our bodies can readily take up and use
lycopene from watermelon. The experiment, in which volunteers drank either
tomato or watermelon juice as part of a 19-week research regimen, is likely the
first to pinpoint the bioavailability of watermelons lycopene.
Lycopene, also found in guava, red and pink
grapefruit, and tomatoes is an antioxidant that is thought to help protect
against cancer and heart disease.
For further information, contact
Penelope M. Perkins-Veazie,
(580) 889-7395, USDA- ARS South Central
Agricultural Research Laboratory, Lane, OK or
Beverly A. Clevidence, (301)
504-8396, USDA-ARS Phytonutrients
Laboratory, Beltsville, MD
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A tasty new spread made from sunflower seeds
might offer a healthful option for people who--because of allergies--cant
eat peanut butter. About 3 million Americans are allergic to peanuts or certain
tree nuts, according to estimates from the American Academy of Allergy, Asthma,
and Immunology.
ARS scientists at the Southern Regional Research
Center, New Orleans, La., worked with colleagues at Red River Commodities,
Inc., Fargo, N.D., to develop a better way to process the sunflower seeds.
Their technique captures the unique, nut-buttery taste when blended with
ingredients needed to make a spreadable product. The company officially
unveiled their product at the Institute of Food Technologists annual meeting in
June.
Sunflower seeds provide protein, fiber,
vitamin E, zinc and iron.
For more information, contact
Isabel Lima, (504) 286-4515,
USDA-ARS Southern Regional
Research Center,New Orleans, LA
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When do we begin forming our preferences for
certain foods? Perhaps as early as infancy. A new study at the ARS
Childrens Nutrition Research Center, Houston, Texas, may reveal whether
thats the case.
Some 44 Houston-area moms and their 3- to
12-month-old infants will participate in this unique investigation.
To learn more, scientists will work with new
mothers to find out how their babies food preferences change through 12
months of age. The research team will also follow babies growth over the
course of the study. Findings may help parents establish healthy eating
patterns for their children.
For more information, contact
Jennifer O. Fisher, (713) 798-6766,
USDA-ARS Childrens Nutrition
Research Center at Baylor College of Medicine, Houston, TX
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An analysis of health data from nearly 8,400
American men and women provides new insight into the link between high levels
of the amino acid homocysteine and increased risk of heart attack and stroke.
The research may also help explain why the link has not always shown up in
earlier studies.
For men over 40, the correlation between high levels
of homocysteine in blood (greater than 12 micromoles per liter) and high risk
of vascular disease began to decline with age. Among women over 40, a strong
link between high homocysteine and high risk was found only in those who were
post-menopausal.
ARS-funded scientists at the Jean Mayer USDA
Human Nutrition Research Center on Aging in Boston, Mass., reached these
conclusions from their analysis of data about men and women, age 17 to over 70
years, who participated in the third National Health and Nutrition Examination
Survey, or NHANES III.
Homocysteine can build up to high levels in
people who do not get enough B vitamins, most notably folate. The body uses
these nutrients to convert homocysteine into harmless compounds. Smoking, high
blood pressure and consuming too much alcohol or caffeine can also lead to high
homocysteine. Eating grain products fortified with folate can help keep
homocysteine at healthy levels.
The researchers published their findings in
the Journal of Nutrition (2000, vol. 130, no. 6, pp. 3073-3076)
For more information, contact
Jacob Selhub, (617) 556-3191,
Jean Mayer USDA Human Nutrition Research
Center on Aging at Tufts University, Boston, MA
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Beneficial soil-dwelling bacteria may protect
tomorrows potatoes against dry rot fungus and unwanted sprouting. Strains
of friendly Pseudomonas and Enterobacter bacteria, harmless to
humans, can form a biological bandage to prevent the primary dry
rot fungus, Fusarium sambucinum, from sneaking into spuds via nicks and
cracks in the tubers skin.
Preliminary tests by scientists based at the ARS
National Center for Agricultural Utilization Research, Peoria, Ill., indicate
that spraying potatoes with the bacteria can reduce rot by 59 percent or more.
The bacteria may prove an effective
alternative to chemical fungicides. What's more, the microbes may thwart
sprouting of stored spuds. Several strains stopped tubers sprouting by 40
to 70 percent, the researchers report.
For more information, contact
Patricia J. Slininger, (309)
681-6596, USDA-ARS National Center for
Agricultural Utilization Research, Peoria, IL
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Americans who eat meals high in carbohydrate
may consume less fat, carry less fat on their bodies, and achieve more of the
daily recommended intakes for essential nutrients. Thats in contrast to
people who eat fewer carbs in relation to protein and fat. Scientists at the
ARS Beltsville Human Nutrition Research Center found this out in their analysis
of data from the U.S. Department of Agricultures 1994-1996 Continuing
Survey of Food Intakes by Individuals.
The researchers evaluated the amounts of
carbohydrate, fat and protein consumed by 10,014 adult men and women. The
scientists published their conclusions in the June 2002 issue of the Journal
of the American College of Nutrition (vol. 21, no. 3, pp. 268-274).
For purposes of this study, adults were
considered high-carb eaters if carbohydrate made up 55 percent or more of their
total daily calories. This carbohydrate came from such foods as bread, pasta,
rice, fruits and vegetables.
More individuals in the high-carb group had
Body Mass Index, or BMI, scores closer to recommended targets than did survey
particiapants who consumed fewer carbs. A BMI score can indicate whether an
individuals weight is normal.
For more information, contact
Shanthy A. Bowman, (301) 504-0619,
USDA-ARS Beltsville Human Nutrition
Research Center, Beltsville, MD
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Brown rice that used to require up to 50
minutes to cook now can be tender and ready to eat in only 15, if processed by
a novel technique. ARS scientists in New Orleans, La., developed the procedure.
The reduced cooking time makes this nutritious food more convenient to serve
and should thus increase its appeal.
The ARS technique requires air-blasting the brown rice
kernels with rice flour at the processing plant. That leaves microscopic holes
that allow the rice to more readily absorb water during cooking--and become
tender sooner. The technique doesnt harm the taste or texture of the
grains, scientists attest.
The researchers are working with
food-processing industry specialists to further develop the innovative
procedure.
Brown rice, which is simply white rice with
its outer layer still in place, is a source of fiber, thiamine, niacin, vitamin
B6, magnesium, zinc and several other nutrients.
For more information, contact
Harmeet S. Guraya, (504)
286-4258, USDA-ARS
Southern
Regional Research Center, New Orleans, LA
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Scientists dont yet know for certain
whether a high-protein regimen leaches calcium from our bones. But ARS-funded
researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at
Tufts University, Boston, Mass., have now provided new data on this subject.
In a 3-year study with more than 300 men and
women over age 65, the scientists found that, on average, there was no loss in
bone among volunteers who ate meals high in protein as long as they took a
daily supplement of calcium and vitamin D. The supplements ensured that they
met their daily Recommended Dietary Intake of these nutrients. Vitamin D is
known to enhance calcium absorption.
In contrast, a higher protein intake did not
appear to protect against bone loss in volunteers who were not taking calcium
and Vitamin D supplements.
Details are in the April 2002 issue of the
American Journal of Clinical Nutrition (vol. 75, no. 4, pp.
773-779).
For more information, contact
Bess Dawson-Hughes, (617) 566-3064,
Jean Mayer USDA Human Nutrition Research
Center on Aging at Tufts University, Boston, MA
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Teens who eat breakfast are two to five times
more likely than their breakfast-skipping counterparts to get at least
two-thirds of the daily Recommended Dietary Intakes of vitamins A, D, B2, B6
and folate; and of minerals such as calcium, iron, magnesium and phosphorus.
Too, breakfasting teens consume less fat and get higher amounts of protein and
carbohydrates.
In contrast, breakfast-skippers consume
higher amounts of fat. These finding are from a new study of more than 700
ninth-graders in New Orleans, La. Scientists at the ARS Childrens
Nutrition Research Center at Baylor College of Medicine, Houston, Texas,
describe the research in the Journal of Adolescent Health, 2002 (vol.
27, no. 5, pp. 314- 321).
The study updates earlier investigations
which had shown that teens who skip breakfast make poorer food choices, are
unlikely to compensate for missed nutrients by the end of the day, and are more
likely to have a higher Body Mass Index, or BMI. A high BMI is often indicative
of overweight.
During the past 25 years, more and more
Americans--especially 15- to 18- year-old females--have chosen to skip
breakfast.
For more information, contact
Theresa A. Nicklas, (713) 798-6766,
USDA-ARS Childrens Nutrition
Research Center at Baylor College of Medicine, Houston, TX
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Tomatoes richer in the antioxidant lycopene
have been developed by ARS and Purdue University biotechnologists. A serving of
one to two of the high-tech tomatoes provides the 10 milligrams of lycopene
that some nutritionists recommend we consume daily. In contrast, about 10 or
more conventional tomatoes are needed to provide this same quantity of
lycopene.
Researchers found that genetically engineering
tomatoes to boost levels of naturally occurring compounds called polyamines
increased the tomatoes lycopene levels. Their work, published in the June
2002 issue of Nature Biotechnology (vol. 20, no. 6, pp. 613-618), is the
first to show a link between high levels of polyamines and enhanced lycopene
content.
The researchers are seeking industry partners
to commercialize the new tomatoes.
For more information, contact
Autar K. Mattoo, (301) 504-7380,
USDA-ARS Vegetable Laboratory,
Beltsville, MD
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Kids cholesterol levels could affect
their health later in life, according to scientists from the ARS
Childrens Nutrition Research Center at Houston, Texas. Researchers tested
the cholesterol levels and recorded foods eaten by 1,182 children at one point
when the kids were third graders and once again when they were in the fifth
grade. The scientists found that total cholesterol closely correlated with the
amount of fat that youngsters consumed.
The researchers note that reducing the amount
of saturated fat that children eat, increasing the amounts of fruits and
vegetables they are served, and encouraging them to exercise should help keep
their cholesterol counts at healthy levels. An article in the April 2002
Journal of the American Dietetic Association (vol. 102, pp. 511-517) has
details.
For more information, contact
Theresa A. Nicklas, (713) 798-6766,
USDA-ARS Childrens Nutrition
Research Center at Baylor College of Medicine, Houston, TX
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