Soy probably has its greatest effect in premenopausal women. Genistein, a major phytoestrogen in soy, is a weak estrogen that can bind to estrogen receptors on cells. This blocks human estrogen's ability to bind to cells and promote breast tissue growth. However, in postmenopausal women, who have little of their own estrogen, genistein could act like estrogen and increase breast cancer risk in some women. Until we know more, it is always good to include a variety of foods in your diet.
Soy can be a healthy addition to a balanced diet.
People at risk for estrogen-sensitive cancer should talk to their doctor before adding soy to their diets. Below is a list of soyfoods and their isoflavone content. Soyfoods are available at most grocery and specialty food stores. In addition to the health benefits they provide, they can add variety and texture to meals. Incorporating soy into your diet is easy.