Soy isoflavone supplementation could reduce body weight and improve glucose metabolism in non-Asian postmenopausal women—A meta-analysis

• Published in: Nutrition (Burbank, Los Angeles County, Calif.) Vol. 29; no. 1; pp. 8 - 14
• Main Authors: Zhang, Yun-Bo, M.D, Chen, Wen-Hua, Ph.D, Guo, Jing-Jing, M.D, Fu, Zheng-Hai, M.D, Yi, Cheng, M.D, Zhang, Ming, M.D, Na, Xiao-Lin, Ph.D
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 2013; Elsevier; Elsevier Limited
• Subjects: Aged; Biological and medical sciences; Blood glucose; Blood Glucose - metabolism; body mass index; Body weight; Body Weight - drug effects; confidence interval; Diabetes; Dietary Supplements; Fasting - blood; Fasting insulin; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Gastroenterology and Hepatology; Glucose; Glycine max; Hormone replacement therapy; Humans; Insulin; Insulin - blood; Isoflavone supplementation; Isoflavones - administration & dosage; meta-analysis; Metabolic disorders; Metabolism; Middle Aged; Postmenopause - blood; Postmenopause - drug effects; Randomized Controlled Trials as Topic; Studies; systematic review; Vertebrates: anatomy and physiology, studies on body, several organs or systems; weight loss; women; Blood glucose; Isoflavone supplementation; Fasting insulin; Body weight; Human; Isoflavone; Pancreatic hormone; Fasting; Glucose; Soybean; Metabolism; Insulin; Blood; Feeding; Grain legume; Postmenopause; Female; Carbohydrate; Supplementation; Fast
• ISSN: 0899-9007; 1873-1244
• DOI: 10.1016/j.nut.2012.03.019

Abstract Objective The objective of this study was to conduct a systematic review and a meta-analysis to confirm the effects of soy isoflavone supplementation on body weight, fasting glucose, and insulin level in non-Asian postmenopausal women. Methods We searched the PubMed, EMBASE, and Cochrane databases up to October 2010 for randomized controlled trials regarding the effects of isoflavone supplementation on body weight, fasting glucose, and insulin level. Pooled estimates and 95% confidence intervals (CIs) were calculated by the fixed-and-random-effects model. Results Nine studies with 528 participants for body weight, 11 studies with 1182 participants for fasting glucose, and 11 studies with 1142 participants for fasting insulin were included, respectively. Significant reductions were found in body weight [weighted mean difference (WMD), −0.515; 95%CI: −0.895 to −0.134; P = 0.008), glucose level (WMD, −0.189; 95%CI: −0.344 to −0.033), and fasting insulin level (WMD, −0.940; 95%CI: −1.721 to −0.159) with soy isoflavone supplementation compared with placebo control group in non-Asian postmenopausal women after adjusted by unpublished studies. Furthermore, isoflavone supplementation in shorter duration (<6 mo) could significantly reduce body weight (WMD, −0.506; 95%CI: −0.888 to −0.124; P = 0.009) and longer duration (≥6 mo) could significantly reduce blood glucose in postmenopausal women (WMD, −0.270; 95%CI: −0.430 to −0.110; P = 0.001). Meanwhile, more reduction in body weight was observed in the lower dose subgroup (dose < 100 mg). Moreover, it is more effective to reduce body weight and fasting insulin level with soy isoflavone supplementation in normal weight (body mass index < 30) than obese (body mass index ≥ 30) women. Conclusions This meta-analysis showed soy isoflavone supplementation could be beneficial for body weight reduction, glucose, and insulin control in plasma. Large and well-designed studies are recommended to confirm this conclusion.