S-equol is a major intestinally-derived bacterial metabolite of daidzein, one of the principal isoflavones found in soybeans and most soy foods.
S-equol has a similar structure to estrogen, and binds to estrogen receptors to exhibit estrogenic activity.
S-equol has been shown to bind to estrogen receptors (ER)
α and
β and to effectively activate both receptors, although with greater transactivation of ER
β. It has been proposed that the ability to make
S-equol when soy is consumed may be an important factor in determining the clinical efficacy of a soy diet, the so-called “equol hypothesis”. Equol has many beneficial effects on menopausal women. However, equol production depends on the individual’s intestinal flora; and research has shown that only 30 to 50% of individuals in the populations studied are capable of producing equol from daidzein. A lactic acid bacterium,
Lactococcus garvieae (
Lactococcus 20-92 strain), with equol-producing capabilities was identified and isolated from human feces. Recently, we standardized the production of an
S-equol supplement (SE5-OH) using this strain. Reports suggest that the
S-equol supplement contributes positively to menopausal symptoms, bone health, metabolic syndrome and skin aging. In this paper, we introduce new insights into equol or SE5-OH based on epidemiological and clinical study.
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