Commercial preparations containing isoflavones -- including over-the-counter supplements and additives to “multi” supplements and fortified foods (such as candy bars) -- are marketed to provide a variety of health benefits such as reducing menopause hot flashes. Studies have shown that eating soy foods (such as tofu, tempeh, soy milk, or soy nuts) or using a commercial supplement reduces hot flashes about 15% better than a placebo.

Women who seek relief for mild hot flashes may want to give dietary isoflavones a try. Most hot flash studies used about 40 to 80 mg/day. Soy foods seem to produce better results than supplements and they also may be safer, since it’s more difficult to “over-dose” on food than pills. It may take a few weeks to notice any effect. Women with more severe hot flashes may not obtain relief with isoflavones.

While the potential for adverse effects from isoflavones and soy foods in these amounts appears minimal, women should consult with their healthcare providers before using them. Women should also be aware that conflicting studies do exist about the effect of soy on breast cancer. It is not known whether soy can be safely consumed by women with a history of breast cancer.