Menopause ushers in what can be a rather unpleasant period in a woman s life. In response to a natural end in endogenous estrogen production, menstrual cycles become infrequent, cease, and menopause begins. The hallmarks of menopause include hot flashes, vaginal atrophy, concentration problems and sleep disturbances, among other symptoms. Women with these symptoms were routinely treated with hormone replacement therapy (HRT). But in 2002 there was a surprise results from a clinical trial called the Women s Health Initiative (WHI). WHI data showed that the use of hormone replacement therapies increased women s risk of heart disease, breast cancer, stroke, and blood clots. These findings precipitated a mass exodus from standard HRT therapies and encouraged experimentation with alternative practices, setting the stage for increased use of natural supplements, which were supposedly effective against menopausal symptoms.
The impact of these natural alternatives, including soy foods, black cohosh, acupuncture, and daily exercise, is now being weighed by the medical community. A review of plant based estrogens (also called phytoestrogens) found no convincing evidence that they were helpful in curbing menopausal symptoms. In addition, Dr. Clarisa R. Garcia, associate professor of Obstetrics and Gynecology at the University of Pennsylvania, released a new bulletin that attributes the relative success of alternative therapies to a placebo effect. Essentially, she agrees with the use of an innocuous placebo such as food or a supplement if it manages to alleviate symptoms for some women. However, the report suggests the single best therapy against hot flashes for women who still have a uterus remains estrogen in combination with a natural or synthetic progesterone. (Estrogen alone would be recommended for women who have had a hysterectomy, but unopposed estrogen without the effect of a progestin has a relatively high risk of promoting the development of uterine cancer).
Despite lack of hard evidence for the utility of phytoestrogens, ACSH s Dr. Josh Bloom thinks that the estrogenic effect of genistein is at least scientifically plausible. He says, One way to evaluate the potential of a chemical to affect estrogen-based processes is to measure how tightly a given chemical binds to estrogen receptors. Not surprisingly, estrogens bind quite well. After all, this is their job.
He continues, Genistein (see graphic below) does not bind as strongly to estrogen receptors, but it still fits the receptor rather well, so it is not that big of a stretch to predict that it may have some of the same effects.
But, keep in mind, he says, That because soy estrogens come from soy (duh), which is natural, do not kid yourself into thinking that using soy for estrogen replacement is necessarily any safer than doing so using HRT drugs. If the soy products work at all, they do so in the same way.
Therefore, while the original WHI report cautioned against it, HRT in lower doses and for shorter periods of time is still the safe and effective treatment of not only hot flashes but also vaginal atrophy, and helping to maintain bone mineral density. As such, the imperfect HRT remains the most viable option for women experiencing menopausal irritability.
ACSH s Dr. Gil Ross wanted to emphasize that because a substance drug, chemical, food nutrient has a binding affinity with some receptor, making it a biologically plausible effect, that may or may not translate into the real-world, clinical findings. While receptor dynamics are cool, they are only one of many tools used to study the effect of chemicals in biological systems. The studies above indicate that you should not to rely on soy-based phytoestrogens for menopause relief, no matter the binding coefficients thereof.