Science Briefs
Nuts Promote Heart Health
Although many people consider nuts off-limits because of their high fat content, snacking on them appears to protect against heart disease, according to a new analysis by Frank Hu, Ph.D., of the Harvard School of Public Health in Cambridge, Mass.
Hu examined data from 86,000 U.S. women who participated in the Harvard-based Nurses' Health Study, an epidemiological effort conducted from 1980 to 1990. The nurses were grouped according to how often they ate nuts—almost never; once a week to once a month; two to four times a week; and five or more times a week.
Nut lovers smoked less, exercised more, and used supplements more often. After adjusting for these factors, Hu found that women who ate more nuts—five or more servings per week—had only two-thirds the rate of heart disease deaths and nonfatal heart attacks as infrequent nut eaters.
Several possible reasons exist for his findings. First, unsaturated fatty acids in nuts reduce blood lipids. Second, nuts are rich in the amino acid arginine, a precursor of nitric acid, which, in turn, relaxes blood vessels and inhibits clotting. The magnesium, copper, folic acid, fiber and vitamin E content of nuts may also have heart-protecting qualities. Finally, walnuts contain alpha-linolenic acid, an omega-3 fatty acid precursor known to protect against heart disease.
Peanuts were also analyzed, although they are technically not nuts, but legumes. Peanuts were linked to the same health benefits as nuts, but the spreadable derivative, peanut butter, was not. Researchers speculate that the reason for this is because most commercial peanut butters contain harmful hydrogenated oil that counteracts peanuts' healthy components.
The study also revealed that during the course of only 10 years, nut consumption among the female subjects declined nearly 50 percent. Although researchers didn't address the shift in eating habits, it may be that fat-conscious Americans are avoiding nuts when they should be reaching for them.
—British Medical Journal 1998 Nov;317:1341-5
