WINSTON-SALEM, N.C., April 30 (UPI) -- U.S. researchers said too much soy could have an adverse effect on the behavior of men.
Researchers at Wake Forest University said they found in male monkeys, "long-term consumption of a diet rich in soy isoflavones can have marked influences on patterns of aggression and social behavior." Isoflavones are a naturally occurring plant estrogen in soy protein.
"Although considerable attention has been directed at the potentially beneficial effects of isoflavones in reducing the risk of various cancers, osteoporosis, cardiovascular disease and postmenopausal symptoms," the researchers wrote in a recent study, less effort has been invested in studying possible effects on behavior.
People have the concept that soy is only beneficial, said Jay R. Kaplan, professor of comparative medicine and anthropology and one of the investigators. "There is the thought that what is good for some is good for all and more is better," he said.
The research suggests not only does the dose make a difference, but so does the sex of the consumer, even though previous studies have shown no difference in aggression in females given large doses of soy, Kaplan said.
