Bone loss commonly occurs as we age, especially for women. Until recently, women were routinely prescribed estrogen after menopause to prevent bone loss and fractures.

When a Women's Health Initiative study revealed that estrogen therapy increased the risk of breast cancer, stroke and Alzheimer's disease, many women stopped taking their hormones and started looking for alternative treatments for bone loss.

One alternative therapy is genistein, the plant hormone found primarily in soy foods. Previous studies have suggested that soy hormones, also known as isoflavones, may help prevent bone loss, but data have conflicted.

A study from Italy published in 2007 in the Annals of Internal Medicine has provided further evidence that genistein may in fact protect our bones.

In this study, 389 women with mild bone loss were assigned to receive either a placebo or 54 milligrams of genistein each day for two years. All women received supplemental calcium and Vitamin D.

Bone density, as well as blood and urine markers of bone loss, were evaluated at the beginning and end of the study.

When the study was finished, it was found that the women getting the genistein had an increase in bone density as well as a reduction in markers of bone loss, while the women getting placebo showed the opposite. The study did not look at the incidence of fractures in these women. The main side effect of the genistein was gastrointestinal upset.

Bottom line? Getting soy isoflavones like genistein in your diet may help you reduce bone loss as you age, and less bone loss generally means fewer fractures as well.

Does this mean you should go out and buy a bottle of genistein pills?

We advise caution in this approach, since genistein is a plant hormone, and the safety of long-term exposure to hormone-sensitive tissue like the breasts and ovaries is unknown at this time.

However, including soy foods in your diet, like edamame (soybeans), tofu and soy milk, is a healthy way to capture the benefits of these plant substances.

And, don't forget the other things that are important to maintaining bone health: Take your Vitamin D every day. Get enough calcium and magnesium in your diet. Eat lots of darkly pigmented fruits and vegetables. Don't smoke. Keep up that weight-bearing exercise.

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(Drs. Kay Judge and Maxine Barish-Wreden are medical directors of Sutter Downtown Integrative Medicine program. Have a question related to alternative medicine? E-mail adrenaline@sacbee.com.)