Isoflavones are found in many of the foods we eat, particularly in beans, grains and soy products. They mirror the effects of estrogen on the body and are beneficial because they help decrease LDL-cholesterol (bad cholesterol), provide an antioxidant effect and reduce artery-clogging plaque, which lowers the risk of atherosclerosis. Isoflavones also aid in lowering high blood pressure. Because of the health benefits of isoflavones in food, industry has extracted and packaged them as nutritional supplements.
More recently, genistein, one of these extracted isoflavones, is being added to various supplements because it has been thought to have a positive effect on bone metabolism. Since there are estrogenic effects, the rationale is that this extracted isoflavone will decrease bone turnover and, therefore, improve bone density. However, of all the studies conducted on isoflavone extracts, only one shows evidence that these compounds have any beneficial effect on bone health.
Isoflavones in Food
Isoflavones that we consume in food are safe. The extracted isoflavones in supplements are much higher concentrations than you would normally eat. Supplements with extracted isoflavones, like genistein, usually include calcium and vitamin D; two well established components for bone health. Adding the isoflavone may or may not add additional benefit.
Post menopausal women and women with breast cancer should be particularly careful to avoid extracted isoflavones because of the concentration of estrogenic effects.
There are many important daily steps for bone health: eating foods rich in calcium, getting enough vitamin D, and doing weight bearing exercise.
