Soy Compound May Strengthen Bone
Whether it's a better option than traditional measures remains unclear

(HealthDay News) -- A soy compound has been shown to help build bones in older women, who are especially prone to osteoporosis that results from bone loss.

But that seemingly good news has been tempered by concerns that the compound may be a cancer risk.

Called genistein, the compound is a natural phytoestrogen, which means it acts like estrogen in the body. That's why some experts are worried that it may increase the risk of certain cancers.

Its effectiveness for bone mineral density, though, heartened the researchers who studied it in postmenopausal women.

"After one year, there was a clear difference in the women who got the genistein," the study's co-author, Steven Wilson, a biostatistician at National Jewish Medical and Research Center in Denver, told HealthDay .

The study involved 390 postmenopausal women who had low bone mineral density, though not low enough to be classified as osteoporosis. They were randomly assigned to take either 54 milligrams of genistein or a placebo daily for two years. Each day both groups also took 500 milligrams of calcium and 400 international units of vitamin D, nutrients known to strengthen bones.

After a year, "the bone had not only stopped deteriorating but actually began to reform and become more dense" in the group taking genistein, Wilson said. "The placebo group, still receiving a normal dose of calcium and vitamin D, continued unfortunately their decline."

The genistein group experienced more gastrointestinal side effects than the group that didn't take the soy compound.

Dr. Frank Sacks, professor of medicine at Brigham and Women's Hospital and the Harvard School of Public Health in Boston , told HealthDay that more research on genistein was needed, despite its bone-building potential. "There are safety issues with soy phytoestrogens" related to breast and uterine cancer, he cautioned.

"This study would not change the overall view [among many experts] that soy phytoestrogen supplements should not be taken," Sacks said.

Proven ways to prevent osteoporosis, according to the National Osteoporosis Foundation, include getting adequate levels of vitamin D and calcium and engaging in regular, weight-bearing exercise, such as jogging, walking, dancing or hiking.

Adults younger than 50 need about 1,000 milligrams of calcium each day, and those older than 50 should increase their intake to 1,200 milligrams a day, the foundation advises. However, the body can't make good use of calcium without vitamin D. That means that people older than 50 must be sure to get at least 800 to 1,000 international units of vitamin D daily; those younger than 50 need 400 to 800 international units a day.

In addition, the foundation suggests, people interested in preventing osteoporosis should quit smoking and avoid excessive alcohol use.

On the Web

To learn more about bone health and phytoestrogens, such as soy, visit the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

SOURCES: HealthDay News ; Frank Sacks, M.D., professor of medicine, Brigham and Women's Hospital, Harvard School of Public Health, Boston; Steven Wilson, Ph.D., biostatistician, National Jewish Medical and Research Center, Denver; June 19, 2007, Annals of Internal Medicine ; National Osteoporosis Foundation (www.nof.org)
Author: Serena Gordon
Publication Date: June 30, 2008
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