A soy-derived supplement containing S-equol, developed by a Japanese pharmaceutical company and recently launched in the U.S. as a dietary supplement called Equelle, is being promoted as a “natural” alternative to hormone therapy for menopause symptoms, notably hot flashes. S-equol is thought to counter menopause-related symptoms by binding to estrogen receptors, where it mimics some of the effects of natural estrogen. Does it live up to its claims?
A little background on S-equol
S-equol was originally isolated from the urine of pregnant mares—hence its equine-sounding name. (The S refers to the molecule’s arrangement of atoms, which gives it different physiological properties from other molecules that have the same formula but different structure.) Humans can also produce S-equol when bacteria in the large intestine metabolize daidzein, an isoflavone (phytoestrogen) in soybeans; that is, it is a byproduct of soy consumption. Only very small amounts of S-equol are found naturally in foods.
But not everyone makes the compound when they eat soy, since the ability to do so requires having certain types of bacteria in the intestines, and people vary in the makeup of their gut microbiota. An estimated 50 to 60 percent of Asians are S-equol-producers, compared to only 20 to 30 percent of Westerners—which is one proposed reason why Asian women are less likely to experience menopausal hot flashes.
How much S-equol is produced may also vary from day to day, depending on such factors as health status, diet, and stress. According to a paper in the Journal of Nutrition in 2010, S-equol has a much higher affinity for binding to estrogen receptors than daidzein, “supporting the theory that it may be advantageous to be able to convert daidzein to equol.”
The supplement is produced through a patented process that involves fermenting soy germ to convert its daidzein to S-equol. A handful of studies—mostly from Japan and funded or otherwise affiliated with the manufacturer—suggest that S-equol can reduce severity and frequency of hot flashes.
For instance, a 2012 study in the Journal of Women’s Health of postmenopausal Japanese women (all S-equol nonproducers) found that those who took the supplement for 12 weeks had a 59 percent reduction in hot flashes, compared to 35 percent in the placebo control group.
Preliminary research also suggests that S-equol may reduce other menopause-related symptoms, notably neck and shoulder muscle stiffness (a more common complaint among Japanese women).
Before you consider S-equol
Many questions need to be answered before we would recommend S-equol—including what the optimal dose would be (this may vary by body weight, symptom severity, and otherfactors), whether its effects vary between Western and Asian women (differences in genetics and lifetime exposure to soy may influence results), and whether there are any food or drug interactions. If you already produce S-equol, would there be much, if any, additional benefit? It’s not even clear,though, if the benefits observed are due to S-equol or other products of soy digestion. Moreover, though there have been no major short-term safety concerns, the long-term effects of taking S-equol have not been evaluated. Longer and larger-scale studies are needed, preferably by independent researchers.
Still, if you are suffering from hot flashes that are affecting your quality of life and can’t or don’t want to be on hormone therapy (the most effective treatment for menopausal symptoms), you can talk with your health care provider about trying S-equol under medical supervision. The supplement Equelle is sold exclusively online. It may take at least a month to begin to notice benefits (if youget any). Women who are allergic to soy should not take it.
Also see Cooling Hot Flashes Without Drugs.