Phytoestrogens and Soy: the Debate
Phytoestrogens are compounds that have a mild estrogenic eff ect and are found in whole grains, nuts, and seeds, as well as many other botanicals, fruits, and vegetables. These foods are associated with a reduced risk of breast cancer as well as reduced cancer recurrence.
The controversy becomes heated in the debate over soy- containing foods. This issue is complex, with some studies showing that eating soy early in life can reduce breast cancer risk. On the other hand, consumption of concentrated soy extracts showed increased proliferation of breast cancer cells. Finally, other studies show a protective or neutral eff ect from whole soy foods.
My recommendation for soy is to eat whole soy foods in moderation— no more than a few servings per week, preferably fermented soy foods such as miso or tempeh. Avoid soy protein isolates and supplements containing concentrated soy isofl avones.