Soy Isoflavones May Help Post-Menopausal Women Maintain Bone Health
Isoflavones are phytoestrogens, which are active substances derived from plants that have a weak estrogen-like action. A recent study suggests that soy isoflavone supplementation may help maintain bone health in post-menopausal women by increasing calcium retention by as much as 7.6%.
Participants in the study included 24 postmenopausal women who were prescreened for their ability to convert daidzein to equol. Equol is a isoflavandiol that may help with bone health, skin health, and physiological changes during menopause.
The women were given five soy isoflavone supplements that consisted of two doses of genistein-rich soy supplement and three doses of mixed isoflavones in various proportions. They were also given a bisphosphonate, which is an antiresorptive medicine that slows or stops the natural process that dissolves bone tissue. Each intervention was given sequentially for 50 days, followed by a 50-day washout period.
A total isoflavone dose of 105.23 mg that consisted of genistein, daidzein, and glycitein was found to be the most effective at increasing calcium retention. Specifically, that dose increased calcium retention by 7.6%. In comparison, the genistein-rich soy supplement consisting of 52.85 mg/d of genistein only increased bone calcium retention by 3.4%.
Bisphosphonate had the highest effect on bone calcium retention with an increase of 15.3%. However, it can have adverse side effects such as upset stomach, inflammation, and erosion of the esophagus.
The researchers also looked at the women’s ability to produced equol and whether that influenced the results. Only a third of Caucasians have the correct gut microflora to convert daidzein into equol, and fewer than 13% of the women in study turned out to be equol producers. The researchers found that the ability to produce equol did not enhance the bone protective effect of soy isoflavones.
Researchers from Purdue University, Indiana University School of Medicine, and the University of Alabama at Birmingham conducted the study. It was published in the September 2015 issue of The American Journal of Clinical Nutrition.
Other studies have found that isoflavones, particularly those derived from soy, may reduce menopause symptoms, reduce bone loss and decrease the risk of prostate cancer.
Maintaining a diet rich in fresh fruits and vegetables, eating more soy products and drinking green or white tea are all good ways to increase your isoflavone consumption.