As the most common symptom reported by women going through menopause—sometimes persisting for several years beyond menopause—hot flashes can be severe enough to interfere with certain activities and with sleep. Until recently, hormone therapy was a popular treatment for hot flashes, but safety concerns about estrogen therapy have caused many women to seek alternative remedies. One increasingly popular natural alternative is soyfoods.
It’s been more than 20 years since scientists first proposed that soyfoods might alleviate or prevent the onset of menopausal symptoms. Soyfoods are essentially unique sources of isoflavones, which are commonly classified as plant estrogens because they have estrogen-like effects in some instances. In Japan, where soyfoods are a common dietary staple, women are far less likely to suffer from hot flashes compared to western women.
In the most recent study to test the potential benefits of isoflavones, postmenopausal women consumed either 30 milligrams of genistein, the main isoflavone in soyfoods, or a placebo. The daily 30 milligram supplement used in the study provides the amount of genistein found in about two servings of soyfoods. Over the 12 week study, women taking the placebo had around 27 percent fewer hot flashes per day than before the study started. (For a number of reasons, hot flash studies always show a strong placebo effect.) In comparison, the women consuming genistein saw their number of hot flashes drop by 51 percent or nearly twice the decrease seen in the placebo group. These results are consistent with earlier research on soy and hot flashes.
For women who have frequent and severe hot flashes, a 50% decrease could mean a significant improvement in the quality of life. With the wide availability of a variety of soyfoods, it’s easy to incorporate two servings into daily menus—making soy a simple approach to reducing hot flashes.
Evans M, Elliott JG, Sharma P, Berman R, Guthrie N. The effect of synthetic genistein on menopause symptom management in healthy postmenopausal women: A multi-center, randomized, placebo-controlled study. Maturitas 2010.