Bottle feeding by premature infants may be easier if they can control milk flow.Before premature infants can be bottle-fed, they must demonstrate they can use the bottle safely and efficiently. During bottle feeding, milk may flow too fast for some babies. As a result, it could get into airway, putting the baby at risk of choking. A recent study examined whether infants who are allowed to pace milk flow can better coordinate sucking, swallowing and breathing. This was achieved by holding the bottle so that the top of the milk is level with the baby's mouth. With this arrangement, premature infants fed 50 percent more efficiently than with bottles held at a steeper angle. This practice is used at Texas Children's Hospital for infants having feeding trouble. If further study confirms this benefit, it might be another way to assist infants who have difficulty feeding, especially low-birth-weight infants. Children's Nutritional Research Center at Baylor College of Medicine, Houston, TX Robert Shulman, (713) 798-7145, rshuman@bcm.tmc.edu

Baylor College of Medicine, Department of Pediatrics Chantal Lau, (713) 770-3813,clau@bcm.tmc.edu

Vegetarians who include milk and eggs in their diets can meet their zinc requirements by eating plenty of whole grains and legumes such as beans and peas, researchers have found. The researchers studied 21 women who consumed both a lacto-ovo vegetarian diet–one containing milk and eggs but no other animal products–and a typical U.S. diet for 8 weeks each. Among its many functions, zinc helps the body guard against infections and repair wounds. In the U.S., however, meat is the major source of zinc. It's important to know if the nearly 2 million U.S. lacto-ovo vegetarians may be depriving themselves of adequate zinc, particularly since typical vegetarian diets contain 10 to 30 percent less zinc than non-vegetarian diets. They also contain a lot of fiber and phytate, which tend to reduce absorption of minerals such as zinc. In the study, the vegetarian diet supplied 14 percent less zinc despite efforts to include high-zinc foods. And the women absorbed 21 percent less zinc from the vegetarian diet, putting their absorption deficit at 35 percent. However, they absorbed enough to replace what they excreted, and their health remained good. In fact, the two diets produced very little difference in balance measurements–absorption minus excretion–for zinc and several other minerals. The women's iron status was also assessed, because the body absorbs iron much more readily from animal foods than from plant foods. The women absorbed 70 percent less iron while eating the vegetarian diet, but they showed no signs of iron-poor blood after eight weeks. Grand Forks Human Nutrition Research Center, Grand Forks, ND Janet R. Hunt (701) 795-8328,jhunt@gfhnrc.ars.usda.gov

New findings dampen the prospect that levels of leptin, a hormone-like chemical signal in the body, may explain differences in body fat among people. Scientists at an ARS-funded research center in Boston found no relationship between the amount of leptin circulating in the blood of 61 men and women and the total number of calories they burned each day or their metabolic rate while resting or after eating. The study volunteers ranged in age from 18 to 81 and none were obese. Leptin has become a hot area for obesity research since the discovery of a mutation in the mouse leptin gene that increases the animals' appetite while lowering their metabolic rate. But the researchers concluded that leptin doesn't influence energy regulation in adults by increasing their energy expenditure. In a study by others, young children with higher leptin levels reportedly burned more calories during physical activity. But the recent study indicates adults apparently lose their responsiveness to this signal. Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts, Boston, MA Susan B. Roberts, (617) 556-3237,roberts_em@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

Healthier ice cream? Sounds too good to be true, but it could become a reality, thanks to a new product that enhances the nutritional quality of low-fat foods. Nu-trim, a new product ARS scientists made from oat and barley flours, may help lower blood cholesterol levels in some people. Nu-trim contains a high concentration of beta glucan, a soluble gum found in oat and barley grains. Beta glucan may reduce blood cholesterol and may prevent it from attaching to blood vessel walls. Described as a "nutraceutical," Nu-trim is part of a new generation of food ingredients designed to boost a food's nutritional value without changing its taste and texture. Nu-trim is similar in texture to dairy and coconut cream, so it can replace fatty creams in baked goods, salad dressings, sauces and ice cream. inglett@mail.ncaur.usda.gov National Center for Agricultural Utilization Research, Peoria, IL George Inglett, (309) 681-6363,inglett@mail.ncaur.usda.gov

A 3-month ARS study of the essential B-vitamin folate provides new evidence that its Recommended Dietary Allowance for women–180 micrograms a day–may be too low.Results from lab tests of 10 healthy women, age 49 to 63, who volunteered for the study suggest that higher levels of folate might be needed to prevent unhealthful buildup of the amino acid homocysteine or to forestall proliferation of white blood cell components called micronuclei. The micronuclei buildup is an indicator of DNA damage. Volunteers lived at the ARS research center in San Francisco for the experiment. They ate only foods specially prepared and precisely measured for folate content. Their low-folate regimen was followed by stints in which they received 160 to nearly 300 percent of the RDA. The higher-folate phases help researchers assess how much folate–over and above the current RDA–is required for good health. Findings can be used by the panel of experts who set America's guidelines for folate intake. Good sources of folate include orange juice, liver, eggs, dark green leafy vegetables, peas, beans, nuts and seeds. In studies elsewhere, adequate folate has been linked to decreased risk of spina bifida, other birth defects, cardiovascular disease and stroke. Western Human Nutrition Research Center, San Francisco, CA Robert A. Jacob, (415) 556-3531,rjacob@whnrc.usda.gov

New findings confirm that long-term use of vitamin C supplements substantially reduces the risk of cataract––a clouding of the eye's lens. Scientists at an ARS-funded center in Boston collaborated on the study with colleagues at Harvard University's Nurses Health Study. Among 247 women studied, those who took vitamin C supplements daily for more than 10 years had 77 percent fewer early-stage cataracts than those who didn't supplement. That's less than one-quarter as many clouded lenses. The women who took the supplements for less than a decade had no detectable difference in cataract prevalence. Supplement users took at least 300 milligrams of vitamin C daily in addition to food and multivitamin sources. The findings emphasize that cataracts take many years to develop and, therefore, require a long-term solution, the researchers say. They selected participants from Harvard University's Nurses Health Study, begun in the 1970s, based on high and low vitamin C intakes. None of the women had been previously diagnosed with cataracts. Each nurse had reported food and supplement intake several times before being examined for signs of lens clouding. A 1992 report from the larger nurses' study found that 10-plus years of taking vitamin C supplements was associated with far fewer cataract surgeries. Cataracts are thought to result from oxidation of lens proteins. Vitamin C appears to prevent this oxidation. Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts, Boston, MA Allen Taylor/Paul F. Jacques, (617) 556-3155/3237; taylor_c1@hnrc.tufts.edu

paul@hnrc.tufts.edu

Older people might reduce their risk of gaining weight by eating smaller, more frequent meals. The finding comes from a study comparing the fat-burning ability of eight women in their 20s with another eight in their 60s and 70s. The seniors kept pace with their juniors after eating 250- and 500-calorie meals. But they couldn't match the younger group's fat-burning rate after a 1,000-calorie meal. Fat oxidation was about 30 percent lower in the older women after the big meal. That's not good, because dietary fat that doesn't get burned gets stored as body fat. The researchers recommend that seniors eat fewer calories at a sitting, but eat more often to ensure getting enough nutrients. They also suggest older people exercise to increase skeletal muscle and fitness. This may offset the fat-burning deficiency. The study was the first to measure fat oxidation after eating. It was aimed at revealing underlying causes behind the age-related increase in body fat, which typically doubles between the ages of 20 and 50 to 60 years. The body fat increase is linked to several diseases, including cardiovascular disease and non-insulin- dependent diabetes. The findings support several studies that suggest a drop in fat oxidation plays a role. On average, U.S. women in their 60s and 70s consume about 1,400 to 1,500 calories a day. The researchers believe the drop in fat-burning ability is due to hormonal changes. The older women had higher levels of glucagon. This hormone triggers the release of sugar into the blood. With more sugar available to fuel body processes, the women burned less fat. Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, MA Susan R. Roberts, (617) 556-3237, roberts_em@hnrc.tufts.edu

Last Updated: April 29, 1998
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