Postmenopausal women.   Epidemiologic data and clinical experience indicate that estrogen therapy after the menopause offers protection from cardiovascular disease, reduces the extent of osteoporosis, improves cognitive function and relieves menopausal symptoms associated with acute ovarian estrogen loss (Col et al. 1997[] ). Given the poor compliance with conventional HRT that is driven by a fear of possible increased risk of developing breast cancer, and because of side effects (Breckwoldt et al. 1995[] , Zumoff 1993[] ), alternative sources of exogenous estrogen are constantly being sought. Diet has been claimed to offer potential relief from some of the symptomology of the menopause, with vegetarians reporting fewer symptoms, although much of the evidence is anecdotal. Hypothetically, soy isoflavones have the potential to provide an exogenous source of estrogen, and the lower incidences of osteoporosis, breast cancer and menopausal symptoms for women in countries consuming soy as a staple have been attributed in part to the intake of isoflavones (Adlercreutz et al. 1992[] ). The incidence of hot flushes ranges from 70–80% in menopausal women in Europe, to 57% in Malaysia and 18% in China (Sturdee 1997[] ). A number of clinical trials of soy foods have been conducted in postmenopausal women aimed at evaluating the effects on hot flushes and vaginal cytology. Results and conclusions have been variable but promising with regard to an estrogenic effect; however, a strong placebo effect has been observed (Albertazzi et al. 1998[] , Baird et al. 1995[] , Brzezinski et al. 1997[] , Murkies et al. 1995[] ). With a phytoestrogen-rich diet, there was a 40–55% reduction in hot flushes over a 12-wk period in three of these studies, whereas the control diets resulted in a 20–35% reduction in hot flushes. Effects on vaginal epithelia have been reported to range from increases in maturation index to no significant effects (Baird et al. 1995[] , Wilcox et al. 1990[] ). This histological endpoint, however, is highly operator dependent for interpretation. Difficulties in comparing these studies relate to the inconsistencies in the design of the trials and the duration and type of diet used, particularly because the optimum intake of isoflavones required to be effective is yet to be established. In only one of these studies was the level of isoflavone measured in serum (Brzezinski et al. 1997[] ), which may be an important endpoint to monitor in view of the high interindividual variability in metabolism of isoflavones. Further studies must address the issue of dose response; however, given the difficulty of compliance to soy diets, it is probable that this could best be done using supplements. At best, the results from these initial clinical studies are promising and indicative of an estrogenic effect. Effects of soy diets on estrogen-sensitive biochemical markers have been demonstrated in postmenopausal women. Wilcox et al. (1990)[] showed a modest suppression in FSH in a group of postmenopausal women after 6 wk of phytoestrogen-containing diets; in a separate study, a decrease in plasma LH and a stimulation of plasma sex hormone binding globulin (SHBG) and HDL cholesterol concentrations was observed (Gavaler et al. 1991[] ). Serum concentrations of SHBG, an important transport protein of estrogen, were also raised significantly over a 12-wk period in postmenopausal women consuming a phytoestrogen-rich diet comprising soy foods and flaxseed (Brzezinski et al. 1997[] ). These findings contrast with the lack of effect of phytoestrogens on SHBG levels in premenopausal women (Cassidy et al. 1994 and 1995[] [] ), or men (Shultz et al. 1991[] ). In free-living trials in postmenopausal women, 60 g/d soy given over a 4-wk period led to a suppression of LH levels, but there was no significant effect on serum SHBG or estradiol concentration (Cassidy et al. 1998[] ). Collectively, these studies suggest that phytoestrogens are able to act as weak estrogens, particularly in the presence of the low endogenous estrogen status of the postmenopausal woman. Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.