Scientists with ARS and Mississippi State University have found significant
amounts of resveratrol in the skin, pulp, and seeds of muscadine grapes.
Resveratrol is the compound in French wines said to lower cholesterol and the
risk of coronary heart disease.
In the Southeast, muscadines are grown to make juice. But the researchers
are now using muscadine waste from juice processing to make products like
muffins, jams and granola cereal. One-half serving (two ounces) of unfiltered
muscadine juice, one serving of muscadine jam, one medium muscadine muffin, or
one-tenth serving of muscadine sauce give the same dietary amounts of
resveratrol as four fluid ounces of red wine, the researchers say. Their report
is in the American Journal of Enology and Viticulture (vol. 47, pp.
57-61).
Muscadine pureean excellent source of resveratrol, dietary fiber and
some essential mineralsis high in carbohydrates and low in fat and
protein. Powdered puree contains more dietary fiber than oat or rice bran. In
MSU studies, rats fed the powder had lower LDL (bad) cholesterol and higher HDL
(good) levels than animals in the control group.
For more information, contact James B.
Magee, (601) 795-8751,
Small Fruit Research
Unit, Poplarville, MS; or Betty J. Ector, (601) 325-8090, Mississippi State
University, Mississippi State, MS
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Doctors generally interpret a low level of a blood protein called
transferrin to mean a child or elderly person suffers from malnutrition. But
new findings from a study of Jamaican children indicate that low transferrin
can point to another culprit: infection due to poor sanitation. Inadequate
water and sewer sanitation can be a source of intestinal pathogensviral,
bacterial and parasitic. This infection connection can be sneaky. A child will
seem healthy until a repeated, but undiagnosed, infection uses up stored
nutrients. Then classic hunger symptoms develop, possibly confounding the
pediatrician and parents.
A nutritionist at the ARS-funded center in Houston, Texas, collaborated with
researchers from the University of the West Indies to examine infected and
severely malnourished children at the university's Tropical Metabolism Research
Unit in Kingston, Jamaica. Their finding that infection can lower
transferrinand mislead health workersis as important for agencies
serving America's poor as for those conducting international relief efforts.
The findings are published in the Journal of Nutrition (vol. 127, pp.
1469-1474).
Scientists have long known that many children worldwide suffer from
protein-energy malnutrition, or PEM. They get enough calories to survive, but
their diets are low in protein. Infections can tip the nutritional scales
against these children. They reduce the children's appetites and
"tax" available calories to fight illness, leading to malnutrition.
For more information, contact Farook
Jahoor, (713) 798-7084, Children's
Nutrition Research Center, Houston, TX
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Consuming extra calcium from dairy products or supplements could put older
women at risk of low zincunless they get extra zinc, too. That's the
indication from two recent studies. In one of the new studies, lasting about 5
weeks, 18 relatively healthy women past menopause increased calcium intake to
1,360 milligrams daily. That's a little higher than the 1,200 mg now
recommended for people over age 50. The women's zinc absorption dropped an
average 2 mg as did their zinc balance. This happened regardless of whether the
extra calcium came from milk or a calcium phosphate supplement. In a second
study, zinc absorption dropped by half when a group of 10 men and women took a
calcium supplement with a single test meal. But adding nearly 8 mg of zinc to
the calcium supplement offset this effect. The studies were reported in
theAmerican Journal of Clinical Nutrition (vol. 65, pp. 1803-09).
Calcium supplement sales have soared with the growing awareness that high
intakes of this mineral help prevent osteoporosis. Some studies have found that
extra calcium blocks zinc absorption, while others haven't. The researchers
looked for a zinc-calcium interaction in elderly women because, as a group,
they tend to have low zinc intakes. About half of U.S. women consume less than
two-thirds the Recommended Dietary Allowance of 12 mg, according to survey
data. And the amount of zinc people absorb from their meals decreases with age.
While the findings need corroboration before recommending that women who
take extra calcium also increase their zinc intake, they point in that
direction. Zinc's many functions include helping us maintain a healthy immune
system, skin and appetite. The richest dietary sources of zinc are oysters,
liver and beef, followed by whole wheat products, nuts, popcorn, cheddar
cheese, poultry, lamb and pork.
For more information, contact Richard J. Wood, (617) 556-3192,
Jean Mayer USDA Human Nutrition Research
Center on Aging at Tufts, Boston, MA
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Scientists have identified an instigator behind the age-related decline in T
cell function, which coordinates the body's response to an infectious agent or
a would-be tumor. What's more, they were able to reduce the effects of this
instigator in cultured cells. The finding brings science a little closer to
defining how people can maintain a healthy immune system well into old age.
The researchers had suspected that prostaglandin E2 (PGE2) might contribute
to the decline of T cell function in seniors because too much of this
inflammation-producing substance has been shown to suppress T cell activity.
Their suspicions were confirmed when they compared white blood cells from old
and young mice, as reported in Mechanisms of Aging and Development (vol.
93, pp. 59-77).
Macrophages from the old mice indeed produced more PGE2, which reduced T
cell function. While it's not the only culprit, it appears to be an important
one, the researchers say. They also demonstrated that excess PGE2 was due to
increased levels and activity of the enzyme cyclooxygenase, needed to produce
PGE2. That finding is reported in the Journal of Immunology (vol. 159,
pp. 2445-51). Adding the antioxidant vitamin E to the cell cultures reduced
PGE2 levels and improved T cell function. This suggests that people might slow
dysfunction of the immune system as they age by increasing body levels of
vitamin E and possibly other nutrients.
The researchers speculate that excess PGE2 also may contribute to cancer,
cardiovascular disease, arthritis and other diseases of aging because the fatty
substance is found in new tumors as well as in inflamed tissues, including
artery walls.
For more information, contact
Simin Nikbin Meydani, (617)
556-3129, Jean Mayer USDA Human Nutrition
Research Center on Aging at Tufts, Boston, M
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Blackberries are a 90's-type of food. They're rich in fiber and ellagic
acid, a substance recently in the news for its possible anti-cancer properties.
But it's hard to find fresh blackberries without camping out in the produce
section. That may soon change, due in part to the recent discovery that Navaho,
a thornless blackberry variety, has a shelf life of 14 to 21 days compared with
the typical 3- to 4-day shelf life of other varieties. Short shelf life is the
reason for the scarcity of fresh blackberries, even though acreage devoted to
blackberries has been expanding, especially in the South.
Navaho was bred at the University of Arkansas at Fayetteville and released
in 1988 as the first thornless erect blackberry. But the discovery of its
unusual staying power is more recent, the result of post-harvest research by
ARS scientists in Oklahoma. The blackberries maintained their freshness for up
to 3 weeks when stored in industrial coolers. Also, a test shipment of the
berries arrived in the Netherlands just as they were picked: firm,
exceptionally sweet and consistently tasty. This test, reported in
HortScience (vol. 31, pp. 258-261), included a 4-hour refrigerated
shipment from an Oklahoma farm to Dallas/Fort Worth International Airport in
Texas and a 2-day air shipment with dry ice.
For more information, contact Penelope
Perkins-Veazie, (405) 889-7395,
South Central Agricultural
Research Laboratory, Lane, OK
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Animal urine has the potential to become a new source of valuable hormones
and other human drugs, thanks to the collaboration of ARS and New York
University researchers. They have developed transgenic mice that produce, in
the lining of their bladders, human growth hormones that accumulate in the
urine. This model system, the scientists say, shows that the approach could be
used in larger animals that produce more urine. It has the potential to be more
economical than mammary gland "pharming"the current practice of
producing pharmaceuticals in the milk of transgenic animals.
That's because it takes two to three years before the female of most farm
animal species reaches sexual maturity, breeds and lactates for the first time.
By contrast, it would be possible to collect urine from livestock about a day
or two after the animals are born. Another advantage: urine can be taken from
both males and females. Currently, several pharmaceuticals are being
experimentally produced in the milk of transgenic livestock.
The researchers stress that the findings are preliminary and that there are
drawbacks. For one, the bladder produces a much lower concentration of drugs
than does the mammary gland. But the low concentration should not pose a major
problem because purification from urine should be less costly. Reported in the
January 1998 issue of Nature Biotechnology (vol. 16, pp. 21-27), the
success demonstrates that the approach is feasible, but more research is needed
to perfect the system.
For more information, contact Robert J. Wall, (301) 504-8362,
Gene Evaluation and
Mapping Laboratory, Beltsville, MD
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Prolonged hunger in infants may suppress part of the genetic coding for
lactasethe enzyme that digests the milk sugar lactose. That's from a
study of 29 infants recovering from malnutrition at a clinic at the University
of Sao Paulo, Brazil. This may explain a tragic medical mystery that some
pediatricians call "paradoxical re-feeding response." While most
starving children and infants respond well to international treatment efforts,
10 to 20 percent get sicker and die. If validated by further studies, this
finding could generate discussion among physicians on the value of lactose-
free treatments when others don't succeed.
The study infants had not responded well to re-feeding formulas, but
intestinal biopsies ruled out diseases that might have affected recovery.
Researchers compared tissue samples from the malnourished infants to those of
10 well-fed infants hospitalized for a life-saving surgery that required
removal of some intestinal tissue.
This hunger-related intolerance appears to be fundamentally different from
genetically inherited lactose intolerance, the researchers report in
Gastroenterology (vol. 112, pp. 742-751). Unlike adult lactose
intolerance, this condition is temporary. It abates after the child receives
adequate nutrition. Lactose can come in many formsfrom human breast milk
to some nations' international food-relief products. USDA's Farm Service Agency
provides lactose-free corn-soy or wheat-soy blends for U.S. relief efforts
overseas.
For more information, contact Buford Nichols, (713) 798-7018,
Children Nutrition Research Center,
Houston, TX
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From a corn kernel hull, ARS scientists have discovered and applied for
patents on two new products: "Amaizing oil," a corn fiber oil that
may lower cholesterol, and "Zeagen," a valuable white corn fiber gum.
The patent for the corn fiber oil will be jointly held by ARS and the
University of Massachusetts, where feeding studies with hamsters indicated that
the oil significantly lowered total serum cholesterol and LDL
cholesterolthe kind that clogs arteries.
Monsanto, St. Louis, Mo., has licensed the oil technology and plans to
develop a variety of foods and food ingredients aimed at lowering cholesterol.
The gum is extracted in the form of a smooth, white powder, bland in flavor and
aroma, that could be used in foods as an emulsifier, a soluble dietary fiber or
a thickener. The National Starch and Chemical Co., Bridgewater, N.J., is
working with ARS to further develop the gum, which also has potential
industrial applications.
Corn fiber is a low-value byproduct of wet milling, the industrial process
that produces starch, sweeteners, fuel grade ethanol and other products from
corn. About 4 million tons of fiberwhich could yield about 80,000 tons of
corn fiber oilare produced by the corn processing industry each year.
This waste byproduct is now sold for about 5 cents a pound as a low-cost
ingredient in livestock feed. Commercializing these new products could also
lower production costs for fuel ethanol and other corn-derived products
For more information, contact Kevin
B. Hicks, Robert A. Moreau, or
Landis W. Doner, (215) 233-6580,
Eastern Regional Research Center,
Wyndmoor, PA; or Robert A.
Norton, (309) 681-6251, National
Center for Agricultural Utilization Research, Peoria, IL
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ARS scientists have begun a nationwide bacteria hunt to learn where chicken
pathogens can get their start at the farm, so they can be stopped before
reaching consumers. The year-long study is sampling farms in each of the
nation's top poultry-producing areasArkansas, California, Georgia,
Mississippi and the Delmarva peninsula of Delaware, Maryland and Virginia.
The scientists are focusing on 10 broiler production farms. On each farm,
they are taking samples from 25 places to find out which places are likely to
transmit food pathogens. Feed bins, hatcheries and even farmers' boot soles are
being sampled. DNA tests will distinguish the bacteria present in each of the
25 sample sites. The scientists will piece together this information to
determine which sites are top candidates for extra contamination control.
The survey could provide a national picture of where and possibly how
poultry contamination may begin. It could also supply poultry producers with a
new way to track and control bacterial risks. Five top poultry producers have
invited the scientists to comb their farms for this project, the largest of its
kind in the United States.
Salmonella and Campylobacter bacteria are two of the worst
poultry food-safety concerns. They can enter the food supply at any
timein the farm hatchery or the consumer's kitchens. Studies indicated
Salmonella may infect 25 percent of processed poultry carcasses; Campylobacter
may infect up to 90 percent. Proper cooking and handling is the best
protection.
For more information, contact Norman
Stern, (706) 546-3516,
Poultry
Microbiological Safety Research Unit, Richard B. Russell Research Center,
Athens, GA
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New findings from a study of 247 women confirm that long-term use of vitamin
C supplements substantially reduces the risk of cataracta clouding of the
eye's lens. There were 77 percent fewer early-stage cataracts among the women
who took the supplements daily for more than 10 years than among those who
didn't supplement. Women who took the supplements for less than a decade had no
detectable difference in cataract prevalence, according to researchers at the
ARS- funded center in Boston, MA, and colleagues with the Harvard University
Nurses Health Study. Cataracts are thought to result from oxidation of lens
proteins, and vitamin C prevents oxidation, the researchers say.
The findings corroborate a 1992 report that linked 10-plus years of vitamin
C supplements with far fewer cataract surgeries among nurses in the larger
Harvard study. And they emphasize that cataracts are a chronic condition that
takes many years to develop and therefore requires a long-term solution, the
researchers concluded in the American Journal of Clinical Nutrition
(vol. 66, pp. 911-916).
Participants from the 21-year-old Nurses Health Study were selected for this
study based on high and low vitamin C intakes. The supplement users took at
least 500 milligrams of vitamin C daily in addition to food and multivitamin
sources. None of the women had been previously diagnosed with the condition,
and each had reported her food and supplement intake several times before being
examined for cataracts.
For more information, contact Paul
F. Jacques, (617) 556-3237, or Allen Taylor, (617) 556- 3155,
Jean Mayer USDA Human Nutrition Research
Center on Aging at Tufts, Boston, MA
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During this year, interviewers under contract to the ARS will visit the
households of about 5,000 infants and young children across the United States
to gather data on the foods they eat. This children's survey is an extension of
the 1994-96 nationwide food survey, "What We Eat In America," which
covered all age groups. The new survey will cover children up to 10 years old.
Interviewers will collect two days of food intake data as they did during the
1994-96 survey in more than 60 areas around the country.
The information will be combined with food intake data collected during the
larger survey from about 5,700 children up to age 18. The combined data will
provide the Environmental Protection Agency with enough information on
children's food intakes for adequately estimating their exposure to dietary
pesticide residues, as required by the 1996 Food Quality Protection Act. It
will also be useful to planners of other programs that deal with children's
needs, such as food assistance and nutrition education.
For more information, contact Sharon Mickle, (301) 734-5619,
Food Surveys
Research Group, Beltsville Human Nutrition Research Center, Riverdale,
MD
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