Interviewers under contract to ARS will visit households of about 5,000 infants and young children across the U.S. this year to gather data on the foods they eat. The children's survey is an extension of the 1994 to 96 nationwide food survey, What We Eat in America, which covered all age groups. The new survey covers children between birth and 10 years of age. 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 to adequately estimate their exposure to dietary pesticide residues, as required by the 1996 Food Quality Protection Act. It will also help planners of other programs dealing with children's needs, such as food assistance and nutrition education. The interviewers will collect 2 days of food intake data, just as they did during the 1994 to 96 survey, in more than 60 areas around the country. They will ask a parent or care-giver to provide information on foods eaten by children under 6 years old during the previous 24 hours. For children 6 through 9 years, the child will be interviewed with adult help. Interviewers will visit the household again to gather the second day's data for the same child.
Beltsville Human Nutrition Research Center at Riverdale, MD
Sharon Mickle, (301) 734-5619, smickle@rbhnrc.usda.gov

Consuming extra calcium from dairy products or supplements could put older women at risk of low zinc unless they get extra zinc, too. That's the word from two recent ARS 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 of about 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 researchers looked for a zinc-calcium interaction in elderly women because 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. And the amount of zinc people absorb from their meals decreases with age. While the data are too preliminary to recommend that women taking extra calcium also increase their zinc intake, they point in that direction. The richest dietary sources of zinc are oysters, liver and beef, followed by whole-wheat products, nuts, popcorn, cheddar cheese, poultry, lamb and pork.
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts, Boston, MA
Richard J. Wood, (617) 556-3192, wood_mb@hnrc.tufts.edu

Scientists can now assess a person's natural ability to fight infections with a streamlined technique developed by an ARS researcher. The new technique is called "whole blood microculture." It enables scientists to test the ability of a chemical stimulant or antigen to prompt T cells to multiply in their natural milieu--blood. T cells, the "player-coaches" of the immune system, are sensitive indicators of immune function. The new technique costs about one-third less than the standard technique. It also more than triples the number of samples technicians can handle each day. It could lead to routine screening of infants, children, the elderly and others whose immune competence may be suspect. During the past decade, the researcher has tweaked his technique into a foolproof measure of cellular immune competence for nutritional studies. He's still improving it so it can measure the chemicals immune cells use to talk to one another. Other immunologists are developing the technique for other types of research and clinical use.
Beltsville Human Nutrition Research Center, Beltsville, MD
Tim R. Kramer, (301) 504-8459, kramer@307.bhnrc.usda.gov

Scientists have identified a trigger behind the age- related decline in the functioning of T cells, which coordinate the body's response to infection. What's more, the scientists could reduce the effects of this trigger, a fatty substance called prostaglandin E2 (PGE2), in mouse cell cultures. The finding brings science a little closer to defining how people can maintain a healthy immune system well into old age. Researchers had suspected that 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. When they compared the PGE2- producing cells--macrophages--from old and young mice, their suspicions were confirmed. Macrophages cultured from the old mice did indeed produce more PGE2, which, in turn, reduced T cell function. While it's not the only culprit, it appears to be an important one, the researchers say. The researchers also demonstrated that the increase in PGE2 was due to higher levels and activity of an enzyme, cyclooxygenase. This enzyme is used in the production of PGE2. But 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.
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts, Boston, MA
Simin Nikbin Meydani, (617) 556-3129, s_meydani_im@hnrc.tufts.edu

A native American grape could be a source of new health food products. The skin, pulp and seeds of muscadine grapes are loaded with resveratrol, ARS and Mississippi State University scientists have found. Resveratrol is the same compound in wines that is said to lower cholesterol levels and the risk of coronary heart disease. When purified from grapes, resveratrol has also been shown to inhibit tumor development. This research could help promote muscadines as an alternative crop for growers. About half of all muscadines now go into processing juice in the southeastern United States, where the grapes are primarily grown. Some of the remaining waste goes into low-value animal feed, while the rest pose an environmental disposal problem. But new healthy foods are being made from puree powder, produced from the waste skin, pulp and seeds. Muscadine puree powder is higher in dietary fiber than oat or rice bran. Rats that ate the powder had significantly lower LDL (bad) cholesterol levels and higher HDL (good) levels than animals in a control group. One-half serving (2 fluid 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 4 fluid ounces of red wine. Muscadines' newly found health benefits could boost the growth of the grapes--especially since ARS research has reduced from 5 to 3 years the time needed to produce a commercial crop.
Small Fruit Research Laboratory, Poplarville, MS
James Magee, (610) 795-8751, jmagee@ag.gov

Doctors may need to take a second look--for a possible infection--when they interpret a low level of a blood protein called transferrin to mean a child or elderly person is malnourished. While malnutrition is the common diagnosis for low transferrin, recent ARS findings suggest a different problem--a bacterial or viral infection contracted from an inadequate sanitation system. This finding may have special significance for children with a condition called protein-energy malnutrition, or PEM. Children with PEM get enough calories to survive, but their diets are too low in protein. Scientists have long known that many children worldwide suffer from PEM. But the study suggests that undetected infections threaten to tip the nutritional scales against these children by reducing appetite and taxing available calories. A child with repeated undiagnosed infections may suddenly demonstrate classic symptoms of hunger, as well as low transferrin levels, possibly confounding the pediatrician and parents.
Childrens Nutrition Research Center, Houston, TX
Farook Jahoor, (713) 798-7084, fjahoor@bcm.tmc.edu

Do the standards for children's body composition--the ratio of fat, bone and lean issue--reflect the ethnic diversity of American teenagers? A recent study offers new evidence that the standards may need revising so that pediatricians and parents can assess more accurately whether a child is growing up healthy. Growth standards are often used to indicate a child's nutritional status. But currently they refer only to age, gender and weight. The new study included 297 fit, healthy boys aged 3 to 18 years. After accounting for height, weight, age and other factors, the scientists found significant differences in the boys' growth patterns by ethnic group. Their preliminary findings suggest that, compared to the existing standard for boys approaching adolescence, African-American boys store relatively more muscle and bone, while Hispanic boys store relatively more fat. Other institutions studying children's growth standards include the U.S. National Center for Health Statistics and the World Health Organization.
Children's Nutrition Research Center, Houston, TX
Kenneth J. Ellis, (719) 798-7131, kellis@bcm.tmc.edu

Researchers can now "tag" the beta carotene in spinach to track how the body processes this nutrient as it becomes vitamin A in the body. This will allow researchers to see how cooking techniques, including adding spices, affects the vitamin's availability to the body. There is also a need for more information on how the elderly use this nutrient. Much of the body's supply of vitamin A is derived from beta carotene, yet little is actually known about how the body converts this important precursor into vitamin A. In the tagging technique, the plants grow in a solution with safe, non- radioactive forms or isotopes of hydrogen. The plant uses this hydrogen--just as it would use regular, untagged hydrogen--as one of the atomic building blocks for making beta carotene in its leaf tissues. The researchers can then feed the "labeled spinach" to test subjects and track the beta carotene's absorption and conversion into vitamin A through blood tests.
Children's Nutrition Research Center, Houston, TX
Michael A. Grusak, (713) 798-7044, mgrusak@bcm.tmc.edu

Last Updated: February 18, 1998
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