is an isoflavone, a plant-source substance with estrogen-like
qualities (a “phytoestrogen”). Soy is the most abundant common
source of isoflavones, and genistein is the most abundant
isoflavone in soy. Red clover is also a good source of
genistein. Like other phytoestrogens, genistein can have two
opposite effects depending on the circumstances in which it is
taken. In some circumstances, it acts as an antagonist to
estrogen, decreasing the hormone’s effects in the body. In other
situations, it acts as an estrogen substitute, producing
estrogenic effects where the hormone is failing to do so. It can
have these opposite effects because it binds to special sites on
cells called “estrogen receptors,” and mildly stimulates them.
This stimulation is not as strong as that produced by estrogen
itself; however, genistein effectively occupies these sites and
keeps estrogen from having any effect on them. The net result is
that when women with high levels of estrogen take genistein,
estrogenic activity in the body decr