Strategies, drugs and supplements to improve bone mineral density abound. Conflictinng data is also plentiful. Calcium, vitamin D and vitamin K are undoubtedly essential for bone strength. The bulk of data also shows that hormone replacement therapy (HRT) is beneficial for bone health. However, in most cases due to the increased risk of heart disease and cancer, the risks of HRT greatly outweigh the benefits. Research shows that a component found in soy and red clover, isoflavone phytoestrogens, can also have a positive effect on bone, without the dangerous side effects of HRT.  A study published in the American Journal of Clinical Nutrition demonstrated that supplementation of isoflavones in peri- and postmenopausal women slows down bone loss, exerting a protective effect especially in the lumbar spine.

Researchers recruited 177 women to participate in a double-blind,randomized, placebo-controlled trial. Women with a history of breast cancer were excluded from the study. The women were divided into groups given either a red clover-derived isoflavone tablet (containing 26 mg biochaninA, 16 mg formononetin, 1 mg genistein, and 0.5 mg daidzein) or placebo for 12 months. The results showed that women taking the isoflavone supplement experienced a slower loss in bone density of the lumbar spine as compared to placebo. As well, markers of bone formation were also improved with the treatment.

The dose used in this study was relatively low compared to prior trials on soy derived isoflavones, which is likely why there was no discernible difference in actual bone mineral density. As well, the effectiveness noted is likely only applicable to the post-menopausal age group reflecting a mechanism related to attenuation of age-related bone loss mediated by estrogen receptors. This study presents an effective alternative to HRT in bone health for many women. If you are including soy in your diet, make sure you choose organic to avoid genetically modified soy.

2004;79(2):326-333