Tai and colleagues [1] have recently reported that treatment with 300 mg/day of isoflavones (aglycone equivalents) (172.5 mg genistein + 127.5 mg daidzein) for 2 years failed to prevent lumbar spine and total proximal femur bone mineral density (BMD) from declining, as compared with the placebo group. This randomized, double-blind, two-arm-designed study was conducted in a clinical sample of 431 postmenopausal women aged 45–65 years in three centers of Taipei (Taiwan). Each participant also ingested 600 mg of calcium and 125 IU of vitamin D per day. The BMD of the lumbar spine and total proximal femur were measured using dual-energy X-ray absorptiometry at baseline and every half-year thereafter. Serum bone-specific alkaline phosphatase, urinary N-telopeptide of type 1 collagen/creatinine, and other safety assessments were examined regularly. Serum concentrations of isoflavone metabolites, genistein and daidzein, in the intervention group were remarkably elevated following intake of isoflavones ([i]p[/i] < 0.001). However, differences in the mean percentage changes of BMD throughout the treatment period were not statistically significant (lumbar spine, [i]p[/i] = 0.42; total femur, [i]p[/i] = 0.39) between the isoflavone and placebo groups. A significant time trend of bone loss was observed at both sites following repeated measurement of BMD ([i]p[/i] < 0.001). Differences in bone marker levels were not significant between the two treatment groups. The authors concluded that treatment with 300 mg/day isoflavones (aglycone equivalents) failed to prevent a decline in BMD in the lumbar spine or total femur compared with the placebo group.
Author(s)
-
Camil Castelo-Branco
Ob Gyn Senior Consultant, Hospital Clínic Barcelona, and Full Professor, University of Barcelona, Spain
Citations
-
Tai TY, Tsai KS, Tu ST, et al. The effect of soy isoflavone on bone mineral density in postmenopausal Taiwanese women with bone loss: a 2-year randomized double-blind placebo-controlled study. Osteoporos Int 2011 Sep 8. Epub ahead of print
http://www.ncbi.nlm.nih.gov/pubmed/21901480 -
Taku K, Melby MK, Kurzer MS, Mizuno S, Watanabe S, Ishimi Y. Effects of soy isoflavone supplements on bone turnover markers in menopausal women: systematic review and meta-analysis of randomized controlled trials. Bone 2010;47:41323.
http://www.ncbi.nlm.nih.gov/pubmed/20452475 -
Taku K, Melby MK, Takebayashi J, et al. Effect of soy isoflavone extract supplements on bone mineral density in menopausal women: meta-analysis of randomized controlled trials. Asia Pac J Clin Nutr 2010;19:3342.
http://www.ncbi.nlm.nih.gov/pubmed/20199985 -
Kenny AM, Mangano KM, Abourizk RH, et al. Soy proteins and isoflavones affect bone mineral density in older women: a randomized controlled trial. Am J Clin Nutr 2009;90:23442.
http://www.ncbi.nlm.nih.gov/pubmed/19474141 -
Alekel DL, Van Loan MD, Koehler KJ, et al. The soy isoflavones for reducing bone loss (SIRBL) study: a 3-y randomized controlled trial in postmenopausal women. Am J Clin Nutr 2010;91:21830.
http://www.ncbi.nlm.nih.gov/pubmed/19906801 -
Zhang X, Shu XO, Li H, et al. Prospective cohort study of soy food consumption and risk
http://www.ncbi.nlm.nih.gov/pubmed/16157834
