The new study found that the benefits from eating nuts was greatest among thin people, those with high LDL cholesterol and those consuming a fat-rich diet.
But enthusiasm for nuts should be restrained, Sabate said. They are highly caloric, and thus can contribute to obesity. A 3-ounce-a-day limit was recommended.
Jeannie Gazzaniga-Moloo, a spokeswoman for the American Dietetic Association who is in private practice in Sacramento, Calif., said that "nuts can be a very healthy addition to any diet," but she recommends eating somewhat less of them.
She said she suggests that her clients consume about an ounce a day of nuts -- about 22 walnuts, for example, providing about 150 calories -- as part of their daily diet. "They are rich in protein and dietary fiber as well as numerous proteins and in various vitamins," Gazzaniga-Moloo said.
"They should eat the nuts they enjoy," she said. "They can try a variety."
Sabata said that the type of nuts eaten doesn't seem to matter. The study found essentially the same results for walnuts, almonds, peanuts, pecans, hazelnuts, macadamias and pistachios.
"Nuts are a matrix of healthy nutrients, and the most obvious reason for the cholesterol-lowering effect is their unsaturated fat content," Sabate said. "Nuts also contain fiber, vegetable protein, phytoesterols and other antioxidants."
The best evidence for the beneficial effect of nuts, though, has come from studies of walnuts and almonds, he added.
The U.S. Food and Drug Administration has more about cholesterol.
SOURCES: Joan Sabate, chairman, nutrition department, Loma Linda University School of Public Health, Loma Linda, C
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