To evaluate the benefit of phytoestrogens (PhE) in hormone replacement therapy of menopause (HRTM), the Department of Female Endocrinology of the Brazilian Society of Endocrinology and Metabolism convened a group of specialists to perform a bibliographic review. Only articles that met strict scientific methodological criteria were included. PhE exhibit both estrogenic and antiestrogenic actions, mainly on estrogen (E) receptors beta, with much less estrogenic potency than estradiol. PhE content of vegetal sources varies, depending on cultivation, harvesting, storage and industrialization. Conversion of precursors to active phytohormones in the human body exhibits great individual variability. Most studies with PhE was done in vitro or in laboratory animals and could not always be extrapolated to humans. Some studies on the climateric syndrome suggest little improvement of hot flushes but not of vaginal dryness or mood instability. Regarding lipid metabolism, soy-rich food but not isolated isoflavones promotes reduction of total cholesterol, LDL-chol and triglyceride levels, but does not raise HDL-chol as E do, and promotes elevation of lipoprotein (a), which are reduced by E. Although some short-term studies suggest improvement of bone mineral density with isoflavones, no reduction in fracture rate is demonstrated. We conclude that there are no convincing evidences to support the use of PhE or soy-rich food as alternatives to HRTM.
Phytohormones; Phytoestrogens; Menopause; Hormone replacement therapy of menopause
