Doctors often prescribe estrogen to help prevent bone loss and other complications of menopause. Recently, scientists have been looking at soy as a means of protecting bones. Soybeans contain high-quality protein and calcium which are necessary to build strong bones. Americans eat a lot of protein. The more protein we eat, the more calcium we lose from our bodies.
Soy protein causes less urinary calcium loss than animal protein.
Soy also contains calcium in a form our bodies can easily absorb. But, the isoflavones may be the real key to soy's protective action. Isoflavones have been shown to increase bone density in estrogen-deficient rats. Human studies have also shown favorable effects of soy on bone density in postmenopausal women. In one study, positive effects were shown with 90 milligrams of isoflavones daily.