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DISCOVERIES ON DIET
Vegetarian Kids Get an “A” In Nutrition
A University of Minnesota study has shown that middle and high school students who followed a vegetarian diet were more likely to meet the objectives of Healthy People 2010, which includes U.S. Department of Health and Human Services goals for reducing fat and increasing fruit and vegetable intakes.
As reported in the Archives of Pediatric and Adolescent Medicine, of 4,521 participants studied, vegetarians were nearly three times more likely to eat less than 10 percent of calories from saturated fat and twice as likely to eat five or more fruits and vegetables daily. They also consumed less cholesterol and tended to avoid soda and fast food, a dietary pattern that could lower their future risk of heart disease, cancer, and stroke.
Perry CL, McGuire MT, Neumark-Sztainer D, Story M. Adolescent vegetarians: how well do their dietary patterns meet the Healthy People 2010 objectives? Arch Pediatr Adolesc Med. 2002;156:431-437.
Cholesterol May Cloud Your Thinking
Accumulating evidence, including the latest report from the Archives of Neurology, indicates that excess cholesterol impairs memory, language, orientation, and other brain functions. This has prompted the National Institute on Aging to sponsor a major study testing cholesterol-lowering medications against mental decline such as in Alzheimer’s disease. Although the study will take years to complete, there is a safe and easy way to lower cholesterol dramatically, without the cost and side effects of drugs. A vegan diet, consisting of whole grains, vegetables, legumes, and fruits, contains no cholesterol at all and, for most people, causes a rapid reduction in LDL, the “bad” cholesterol shown to clog arteries to the heart, brain, and other vital organs.
Yaffe K, Barrett-Connor E, Lin F, Grady D. Serum lipoprotein levels, statin use, and cognitive function in older women. Arch Neurol. 2002;59:378-384.
High-Protein Diet a Danger To Athletes
University of Connecticut researchers have found another danger in high-protein diets—dehydration. Researchers assigned endurance runners to low-, medium-, and high-protein diets for three successive four-week periods. Blood tests revealed that increasing protein intake causes dehydration. Excess protein leads to a buildup of nitrogen in the blood that must be filtered out in the urine, putting a strain on the kidneys. The runners were unaware they were becoming dehydrated as their thirst did not increase. The American Heart Association has concluded there is no scientific evidence that high-protein diets keep weight off in the long term, and recent reports have suggested that they might aggravate heart problems.
Martin WF. Presentation at the Experimental Biology 2002 conference. April 22, 2002.
Mothers’ Meat-Heavy Diet Spells Trouble for Tots
Moms who eat a meaty diet with few carbohydrates during pregnancy may bear children at risk for high blood pressure as adults. University of Southhampton researchers contacted 626 men and women, aged 27 to 30, whose mothers, as part of a previous study, were instructed to eat one pound of red meat per day during their pregnancies while avoiding carbohydrate-rich foods. Women who reported greater consumption of beef and fish in the second half of pregnancy had children with higher systolic blood pressure as adults. Scientists say the findings may reflect the metabolic stress imposed on the mother by eating an unbalanced diet.
Shiell AW, Campbell-Brown M, Haselden S, Robinson S, Godfrey KM, Barker DJ. High-meat, low-carbohydrate diet in pregnancy: relation to adult blood pressure in the offspring. Hypertension. 2001;38:1282-1288.
ALTERNATIVES TO ANIMAL EXPERIMENTS
Hazardous Pig-to-Human Transplants Proceed
Despite grave risks, scientists continue to experiment with animal-to-human organ transplants, most recently attempting to “humanize” pigs’ organs in hopes of cutting the odds of rejection by the human body. Two companies have bred pigs who lack one of the two usual copies of a gene that makes a sugar, alpha-1-galactose, that is recognized by the human immune system and leads to rejection. The problem is, no one knows whether pigs can even survive without the sugar. While experiments to transplant the altered pig organs into baboons and other animals are being planned, many researchers warn that the end result for humans could spell serious trouble. All pig organs harbor retroviruses capable of infecting transplant recipients, and, theoretically at least, those who come in contact with animal organ recipients.
Monkey Vaccine Tests Fail
HIV is known to mutate and resist traditional AIDS drugs in half of those people being treated for infection. Experiments using the monkey virus, SIV, show that it rapidly mutates to side step the vaccine’s protective effects. Few scientists believe that animal experiments will lead to a useful AIDS vaccine in the foreseeable future.
Barouch DH, Kunstman J, Kuroda MJ, et al. Eventual AIDS vaccine failure in a rhesus monkey by viral escape from cytotoxic T lymphocytes. Nature. 2002;415:335-339.
AN OUNCE OF PREVENTION
Skip Animal Protein to Prevent Kidney Stones
Researchers in Italy studied 120 men with recurrent calcium oxalate kidney stones, assigning half to a diet of normal calcium, but reduced animal protein and salt. The other men were assigned to a low-calcium diet, traditionally believed to discourage recurrence. After five years, the low-animal-protein diet was the winner: Only 12 of these men relapsed compared to 23 of the men on the low-calcium diet. Urinary calcium levels dropped significantly in both groups; however, urinary oxalate excretion increased in the men on low-calcium diets, but decreased in those eating less animal protein and salt.
Borghi L, Schianchi T, Meschi T, et al. Comparisons of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. N Eng J Med. 2002;346:77-84.
Oranges Have Appeal Anyone Can See
The Nutrition and Vision Project (NVP), a cooperative effort of Harvard and Tufts scientists, has discovered that women who consume higher-than-recommended doses of vitamin C may lower their risk for cataracts. The NVP studied 492 women, aged 53 to 73, analyzing their diets over a 15-year period. They found that women under age 60 with a daily vitamin C intake of 352 milligrams or more were 57 percent less likely to develop cortical cataracts than those whose intake was less than 140 milligrams per day. And women under age 60 who had taken vitamin C supplements for at least ten years had a 60 percent lower risk for such cataracts. Vitamin C appears to neutralize free radicals that form within the lens, leading to cataracts.
Vitamin C and cataract risk in women. Harv Womens Health Watch. 2002;9:1.