GIFU, JAPAN. Soy products contain isoflavone a dietary estrogen. Dietary estrogens have effects similar to those exhibited by estrogen produced in the body. Japanese researchers therefore reasoned that soy products and isoflavone (daidzein and genistein) should help alleviate hot flashes in women going through menopause. Their recently completed study proved them right. The study involved 1106 premenopausal women between the ages of 35 and 54 years when first enrolled in 1992. During six years of follow-up 101 women had new moderate or severe hot flashes according to the Kupperman test of menopausal distress. Analysis of food frequency questionnaires completed by the women at entry showed that women with a high consumption of soy products (median intake of 115.9 grams/day) had half the risk of experiencing hot flashes of moderate to severe intensity than did women with a low consumption (median intake of 44.5 grams/day). Correspondingly, the women with a high intake of isoflavone (50.8 mg/day median) had a 58 per cent lower risk of moderate to severe hot flashes than did the women with a low intake (20.5 mg/day median). On the other hand, the women who smoked had a four times greater risk of having moderate to severe hot flashes than did the non-smokers. The researchers conclude that consumption of soy products (tofu, soy milk, miso soup, and soybeans prepared in other ways) is a practical strategy for preventing hot flashes and presents a viable alternative to conventional hormone replacement therapy.
Nagata, Chisato, et al. Soy product intake and hot flashes in Japanese women: results from a community-based prospective study. American Journal of Epidemiology, Vol. 153, April 15, 2001, pp. 790-93