Does Soy Curb Hot Flashes?
Maybe, but Look for Relief From Food, Not the 'Active Ingredient,' Suggests Study
Though all of the patients reported fewer and milder events of hot flashes, flushing, and night sweats, the researchers believe it was due to the soy protein itself -- if not a placebo effect.
"It looks as though the 'whole' food may be effective, but not the isoflavones," Vitolins tells WebMD. "There appears to be some sort of synergy that goes on with the protein -- the whole mix in the food is where you may get the benefit. Maybe the protein or other substances act as a carrier of these molecules that seem to reduce symptoms. But the isoflavones found in supplements themselves don't offer benefit, judging by our study."
Her advice: Continue to eat soy-rich foods, which have also been shown in some studies to help lower cholesterol, increase bone density, and possibly protect against some forms of cancer. But don't rely on supplements.
"This is so important for women to know, because they're going out and buying these isoflavones supplements, believing they help," says Vitolins. "Unfortunately, with protein comes fat, and many women are dieting and therefore don't get enough protein of any type, including soy protein. But it's so important to their overall nutrition. If you look at the Japanese, who have very low rates of menopause symptoms and other health conditions, they're eating soy protein in foods. They don't take supplements."
And the way they eat the soy may provide another clue to their better health. "The benefit in soy might be from consuming it in varying amounts," she tells WebMD. "Estrogen receptors seem more primed when they are hit with soy protein, then don't get a lot, and are then hit again. Japanese women aren't counting their soy intake or the number of isoflavones they consume. Perhaps the best route might be to consume soy in varying amounts, rather than try to consume a continuously high amount every day."
Others studies seem to suggest that more isn't necessarily better -- at least when it comes to soy and its reporting beneficial compounds. In a study last year, researchers at the University of Illinois at Chicago found there was no difference in levels of key sex hormones in the blood -- believed to bring relief from menopausal symptoms -- among women who took varying levels of a soy supplement, even at doses higher than those used in Vitolin's research.