Soy Protein Helps to Maintain Bone Density

soy milkFood supplements containing genistein, a compound found in soy bean, may help increase women’s bone density after menopause, a study suggests.  Researchers found that combining genistein with calcium and vitamin D can help protect post-menopausal women’s bone mass better than calcium and vitamin D alone. 

In fact, women who took the soy compound in the study showed a modest increase in bone density over two years, compared with a small decrease of bone mass among women who used only calcium and vitamin D.

Genistein is a kind of isoflavone, which is a plant chemical that have effects similar to the female hormone estrogen and may have certain estrogen-like effects on humans.  The amount of estrogen among women declines as their menopause progress, thus contributing to bone loss.  Researchers have linked high soy intake from food to a lower risk of osteoporosis, a disease that makes the bones thin and brittle.

However, the amount of pure genistein used in the research to achieve a prominent effect on bone density increase is inconsistent with actual consumption of soy.  The research gave their subjects 54 milligrams of genistein a day, an amount which is equivalent to 2 gallons of soy milk or about 8 pounds of tofu per day.

This study has raised concerns on whether genistein actually prevents bone fractures over time.  Also, a general concern with high doses of estrogen-like isoflavones is whether they might influence the risk of breast or uterine cancers, which the study concludes not so.  The women given with genistein showed no thickening in the lining of the uterus, a sign of adverse hormonal effects.

Nonetheless, the main side effects of genistein intake were gastrointestinal problems like indigestion and constipation.