The effect of genistein on glucose control and insulin sensitivity in postmenopausal women: A meta-analysis

Preclinical studies have revealed the beneficial effects of genistein in pancreatic β-cell functions. The results of randomized controlled trials (RCTs) in assessing the effects of genistein on glucose metabolism are inconsistent, however. The aim of this meta-analysis is to evaluate the effects of genistein on glucose control and insulin sensitivity in postmenopausal women. This study searched the Medline, PubMed, and Cochrane databases, and ClinicalTrials.gov for trials from January 1970 to February 2016. We included RCTs that investigated the effects of genistein on glucose control and insulin metabolism in postmenopausal women. We also performed pooled analyses with weighted mean difference (WMD) and 95% confidence intervals (CI) according to the RevMan 5.3 software with the random-effects model. Seven eligible RCTs with 670 participants were included in the meta-analysis. Compared with placebos, genistein exhibited significant effects in lowering fasting glucose levels (WMD, -6.35mg/dL [95% CI, -10.78 to -1.93]; P=0.005), fasting insulin concentrations (WMD, -1.92μIU/mL [95% CI, -3.04 to -0.79]; P=0.0008), and HOMA-IR values (WMD, -0.74 [95% CI, -1.21 to -0.28]; P=0.002). Genistein significantly improves glucose control and insulin sensitivity in postmenopausal women. Long-term treatment may have greater effects than short-term use. The role and safety of genistein in glucose control in postmenopausal women require further investigation.