The most recent findings on soy and isoflavones were presented in Washington DC on the occasion of the 9th International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment (October 16-19, 2010). A major part of the topics was dedicated to safety and health benefits in menopausal women, and to the issue of soy and breast cancer.
Dr. Yuko Tousen (National Institute of Health and Nutrition, Tokyo) examined the effects of equol supplementation on bone mineral density in Japanese postmenopausal women (Tousen et al. 2010). Initially, she examined the effects of a subcutaneous administration of 0.5 mg/day of equol in OVX mice for 4 weeks, in comparison to 0.03 µg/day estradiol. The administration of equol inhibited bone loss of the whole body and femur in OVX mice without uterine hypertrophy.
In order to confirm these findings under clinical conditions, the working group performed a 1-year clinical double-blind, randomized, placebo-controlled trial using natural S-equol supplementation in 93 non-equol-producing early postmenopausal Japanese women. The women had dietary contributions of 28.8 to 55.7 mg of isoflavones. Subjects were assigned to placebo, 2 mg, 6 mg and 10 mg of S-equol per day. After 12 months of intervention, the markers for bone resorption were significantly inhibited in the 10 mg group as compared with placebo. However, the effect did not last after discontinuation. The application was found safe: Sexual and thyroid hormone concentrations were not influenced by the equol intervention.
References
Tousen Y, Ezaki J, Fujii Y, Ueno T, Uchiyama S, Nishimuta M and Ishimi Y (2010). Effects of an equol supplement on bone mineral desnsity in postmenopausal Japanese women. 9th International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment, Washington DC, 16-19 October.
Clinical effects 