Dietary flavonoids intake and risk of type 2 diabetes: A meta-analysis of prospective cohort studies

Background & aims: Flavonoids may have cardioprotective effects, but epidemiological evidence on the relationship of dietary flavonoids with diabetes has not been systematically assessed. To examine the association between dietary flavonoids and type 2 diabetes, we performed a meta,analysis on this topic. Methods: We searched PubMed through March 2013 for relevant cohort studies that assessed total flavonoids and type 2 diabetes risks. A fixed-effect model was used to calculate the summary risk estimates. Results: Four articles consisting of 6 prospective cohorts that involved 18,146 cases and 284,806 participants were identified. The summary relative risk (RR) of type 2 diabetes for the highest intake of total flavonoids compared with the lowest was 0.91 (95% confidence interval (CI): 0.87-0.96). Furthermore, an increase in the total flavonoids intake of 500 mg/d was associated with a significant risk reduction of 5% (RR = 0.95, 95% CI: 0.91-0.98). In subgroup analyses, the observed beneficial effects were observed in US population, in those mean age >40 years old people and in studies >= 20 years in duration. Conclusions: The present meta-analysis indicates that consumption of dietary total flavonoids is associated with a reduced risk of type 2 diabetes. (C) 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.