Soy contains isoflavones, phytoestrogens (“plant estrogens”) that mimic some of the effects of estrogen. Many women consume soy or soy supplements in hopes of gaining some of the benefits of estrogen while avoiding the side effects of synthetic hormones. Soy may help menopausal symptoms, modestly decreasing hot flashes in some women. Soy protein can improve cholesterol and triglyceride profiles in men and premenopausal women, but may not benefit postmenopausal women, probably because they have a lower baseline estrogen level. Soy might prevent bone loss at or before menopause, but studies indicate it does not protect against bone loss when started in women over age 60. It is not known if soy improves cognitive function or prevents dementia. On the negative side, endometrial hyperplasia (overgrowth of uterine tissue that can lead to cancer) can occur in some women taking chronic, high doses (150 mg/day of soy isoflavones for 5 years). In conclusion, soy should not be the sole source of estrogen replacement therapy. Ask us about other “natural” options, such as bio-identical hormone replacement therapy.