Isoflavoni

Isoflavoni, or isoflavones in English, are a class of flavonoid phytoestrogens found in plants, with soybeans and soy products as the richest sources. The main isoflavones in the human diet are genistein, daidzein and glycitein, often present as glycosides in foods and released during digestion. Isoflavones are part of the broader flavonoid family and share a 3-phenylchroman skeleton.

Dietary sources: soybeans, soy milk, tofu, tempeh, and other soy products are the primary sources. Smaller amounts occur in chickpeas, lentils, and other legumes. Isoflavones are also found in some clover and alfalfa products used for animal feed.

Biological activity: Isoflavones are phytoestrogens that can bind to estrogen receptors, especially ER-beta, and can exert weak estrogenic or anti-estrogenic effects depending on tissue context and endogenous estrogen levels. They can be metabolized by gut microbiota to compounds such as equol, which in some people has enhanced biological activity. Equol production varies and is more common in some populations.

Health effects: Observational and experimental studies have explored possible benefits for menopausal symptoms, bone health and cardiovascular risk, as well as potential effects on cancer risk. Results are mixed, and effects may depend on dose, duration of intake, gut microbiota, and individual factors. Isoflavones are generally considered safe in typical dietary amounts, but high-dose supplements may interact with certain medications or thyroid function and are not universally appropriate for all individuals.