Soy Isoflavones May Help Slow Bone Loss for Postmenopausal Women
Lee Swanson Research Update
A study published in the American Journal of Clinical Nutrition proposes that supplementation with soy germ-derived isoflavones may reduce bone loss in postmenopausal women.
More than 400 postmenopausal women participated in the multi-center, randomized, double-blind, placebo-controlled trial, which used either 80 mg or 120 mg of soy hypocotyl aglycone isoflavones (SoyLife), plus calcium (400 mg) and vitamin D (400 IU).
Only the 120 mg per day dose produced benefits, with significantly reduced loss of whole body bone mineral density (BMD) after both one and two years.
"The attenuated whole body bone mineral density in healthy postmenopausal women for two years probably translates to minimal clinical benefits; yet the long-term significance, particularly with regard to fracture prevention, remains to be determined," wrote the researchers, led by William Wong from the USDA/ARS Children's Nutrition Research Center at the Baylor College of Medicine in Texas.
Wong and his co-workers recruited 403 postmenopausal women aged between 40 and 50 to participate in the study. Smokers and women already suffering from osteoporosis were not allowed to participate. The women were randomly assigned to receive daily supplementation of soy hypocotyls aglycone isoflavones (80 mg or 120 mg) or placebo for two years. All the women were given calcium and vitamin D supplements.
After two years, the researchers recorded a statistically significant smaller reduction in whole body BMD in the women receiving the 120 mg soy isoflavones, compared to the placebo group.
American Journal of Clinical Nutrition 90(5):1433-1439, 2009