New data on soy, hot flashes, and night sweats

A small, short-term, double-blind, Swedish study involving 60 healthy postmenopausal women finds that 60 mg isoflavones daily can reduce hot flashes and night sweats by about half without any negative effects on the endometrium, breasts, or lipid levels.

Researchers gave participants a soybean-based fruit drink containing 60 mg isoflavones or placebo daily for 3 months. They found that in the women receiving the isoflavones, hot flashes and night sweats were reduced by 57% and 43%, respectively, without changes in levels of circulating estradiol or follicle-stimulating hormone and without affecting expression levels of steroid receptors; estrogen receptors α, β, and β_cx; progesterone receptors A and B; or the proliferation marker Ki67. Furthermore, the authors of the study observed no side effects on body weight, lipoprotein profiles, or endometrial thickness as measured by ultrasound.

The researchers concluded that while the findings are encouraging, the question of whether isoflavones can substitute for estrogen replacement requires further investigation.