Glossary · Treatments

Isoflavones

Definition: Isoflavones are phytoestrogens found primarily in soy and red clover, with the major dietary forms being genistein and daidzein. They bind estrogen receptors with low affinity and have been studied for menopausal symptoms with mixed results — modest hot-flash reduction in some trials.

Detailed definition

Isoflavones are a class of phytoestrogens characterized by a 3-phenylchromone structure. The principal dietary isoflavones are genistein, daidzein, and glycitein, found primarily in soybeans, soy products, red clover, and to a lesser extent in chickpeas and other legumes. Isoflavones bind estrogen receptors (especially ERβ) with much lower affinity than estradiol — typically 1/100 to 1/1000. Some women, depending on gut microbiome, can convert daidzein to equol, which has higher receptor affinity and may be the active mediator of phytoestrogen benefits. RCT meta-analyses show modest reductions in hot flash frequency (often 10–25%) with soy isoflavone supplementation, considerably less than HRT or fezolinetant. Dietary soy intake (tofu, tempeh, edamame, soy milk) is generally safe and reasonable for women interested in dietary management; supplements have less safety data, especially for women with breast cancer history.

Why it matters in menopause

For women with mild vasomotor symptoms preferring dietary or supplement approaches, isoflavone-rich diets are reasonable. For women with severe symptoms, prescription options have stronger evidence.

Sources

External references: Wikipedia.

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