Soy isoflavones have a favorable effect on bone loss in Chinese postmenopausal women with lower bone mass: a double-blind, randomized, controlled trial.Author: Chen YM et al. Publication: J Clin Endocrinol Metab. 2003 Oct;88(10):4740-7.
Animal studies have shown that isoflavones can help to prevent osteoporosis because isoflavones can prevent estrogen-related bone loss. However only few data is available for the effects on humans.
The study was a double-blind, placebo-controlled, randomized trial with about two hundred postmenopausal Chinese woman, aged between 48 and 62 years. The woman were divided in 3 groups:
Group 1: received only placebo
Group2: received medium dose isoflavones (0.5 g soy extracts with 40 mg isoflavones)
Group 3: received high dose (1.0 g soy extracts with 80 mg isoflavone).
All woman received 500 mg calcium and 125 IU vitamin D(3) as supplement. Bone mineral density (BMD) and bone mineral content (BMC) of the whole body, spine, and hip were measured at the start aand after 1 year treatment.
Results showed that women from group 3 showed mild, but statistically significantly, higher favorable change rate in BMC at the total hip and trochanter (P < 0.05). Further analyses revealed that the positive effects of soy isoflavone supplementation were observed only among women with lower initial baseline BMC. In conclusion, soy isoflavones have a mild, but significant effect on the maintenance of hip bone mineral density in postmenopausal women with low initial bone mass. Dietary isoflavones: biological effects and relevance to human health. J Nutr. 1999 Mar;129(3):758S-767S