The latest research into the health effects and safety of a soy-based compound called S-equol was described in talks and presentations by experts at a special session on Tuesday, Oct. 19 during the Ninth International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment, held Oct. 16 to 19 in Washington, D.C.

S-equol is a compound resulting -- when certain bacteria are present in the digestive track -- from the natural metabolism, or conversion, of daidzein, an isoflavone found in whole soybeans. Not everyone can produce S-equol after soy consumption, as the production depends on the types of bacteria present in the large intestine and may be influenced by the amount of soy consumed. About 50 percent of Asians and 20 to 30 percent of North Americans and Europeans have the ability to produce S-equol.

Development and ongoing research of a supplement containing Natural S-equol is being conducted by the Saga Nutraceuticals Research Institute of Otsuka Pharmaceutical Co., Ltd. Pharmavite LLC is studying Natural S-equol in a supplement form for the management of menopausal symptoms, including in clinical trials. Pharmavite is the maker of Nature Made® vitamins and minerals and is a subsidiary of Otsuka, and together with Otsuka is one of the sponsors of the Soy Symposium.

S-equol selectively binds to the receptors for the naturally occurring female sex hormone estrogen, with a strong affinity to the estrogen receptor beta. On binding to these receptors, S-equol mimics some, but not all, activities of natural estrogen. Because of these actions at the receptor, it has been proposed that S-equol may alleviate some of the symptoms caused by diminished estrogen production during menopause.

The Soy Symposium, held every two years since 1994, included sessions on the results of clinical trials and epidemiologic studies, the physiological effects of soyfoods and soybean components, proposed mechanisms for the health effects of soyfoods and identification of future research needs.