Phytoestrogens - an alternative to standard hormone replacement therapy?

Due to some severe side effects, "classic" hormone replacement therapy (HRT) is currently being challenged by therapy with phytoestrogens. Particularly soy- and red clover-derived isoflavones are advertised as selective estrogen receptor modulators (SERMs) with only desired and no undesired estrogenic effects. Evidence that this is the case however is scarce. Most studies investigating climacteric complaints did not find beneficial effects. A proposed beneficial effect on mammary cancer is unproven. The majority of studies however indicate an antiosteoporotic effect of isoflavones, while putative beneficial effects in the cardiovascular system are questionable due to the fact that estradiol, which - like isoflavones - increases HDL and decreases LDL concentrations, does not appear to prevent arteriosclerosis in humans. In the urogenital tract, including the vagina, soy- and red clover-derived isoflavones exert no effects. Cimicifuga racemosa extracts are traditionally used for the treatment of climacteric complaints. Evidence is now available that the as yet unknown compounds in Cimicifuga racemosa extracts prevent climacteric complaints and may also have antiosteoporotic effects.