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

Abstract

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 500mg/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.

Keywords: CVD; Diabetes risk; FFQ; Flavonoids; HR; Meta-analysis; OR; RCT; RR; cardiovascular disease; food frequency questionnaires; hazard; odds radios; randomized clinical trial; relative risk.