The soybean plant, a legume, contains specific phytochemicals known as isoflavones. Phytochemicals are nonnutritive substances, in that they contain no vitamins or minerals. Isoflavones are also phytoestrogens. Phytoestrogens are compounds that have mild estrogenic effects. Chick peas and legumes are good sources of isoflavones. Soy has the greatest concentration of these chemicals. Isoflavones have received a good deal of attention for their possible cancer and heart disease-preventive traits. Because of their estrogenlike properties, many believe that isoflavones and other phytoestrogens may one day play a role in post-menopausal health. One isoflavone derivative, ipriflavone, is currently used outside the United States as an osteoporosis therapy. Ipriflavone has had a bone-protective effect in several studies. Further research is needed to understand the systemic effects of this compound before it can be considered a therapeutic approach for osteoporosis prevention and treatment.

Ipriflavone is a synthetic flavonoid derived from the soy isoflavone called daidzein. It promotes the incorporation of calcium into bone and inhibits bone breakdown, thus preventing and reversing osteoporosis. Many clinical trials, including numerous double-blind trials, have consistently shown that long-term treatment with 600 mg of ipriflavone per day, along with 1,000 mg supplemental calcium, is both safe and effective in halting bone loss in postmenopausal women or in women who have had their ovaries removed. Ipriflavone has also been found to improve bone density in established cases of osteoporosis in most but not all clinical trials. Some studies have shown that ipriflavone therapy not only stops bone loss, it also actually increases bone density and significantly reduces the number of vertebral fractures and amount of bone pain.

One double-blind study has failed to confirm the beneficial effect of ipriflavone. In that study, ipriflavone was no more effective than a placebo for preventing bone loss in postmenopausal women with osteoporosis. The women in this negative study were older (average age, 63.3 years) than those in most other ipriflavone studies and had relatively severe osteoporosis. It is possible that ipriflavone works only in younger women or in those with less severe osteoporosis.

Please see "A Discussion of Natural Hormones" by Dr. Ronald Barentsen.