Flavonoid intake and mortality from cardiovascular disease and all causes: A meta-analysis of prospective cohort studies

Background and aims Accumulating studies have suggested that flavonoid intake is associated with a decreased risk of coronary heart disease and cardiovascular disease (CVD). There are many epidemiological studies on flavonoid intake and mortality, but no comprehensive investigation has yet been conducted. To quantitatively assess the association between flavonoid intake and mortality from CVD and all-causes, we performed a meta-analysis of prospective cohort studies. Methods Eligible studies were identified by searching PubMed and Web of Science databases for all articles published up to May 2016 and via hand searching. Study-specific estimates adjusting for potential confounders were combined to calculate a pooled relative risk (RR) with 95% confidence interval (CI) using a random-effects model. Results A total of 15 prospective cohort studies that examined the association between flavonoid intake and mortality from CVD and all-causes were identified. The pooled RR of CVD mortality for the highest versus lowest category of flavonoid intake was 0.86 (95% CI: 0.75, 0.98). By subclass of flavonoids, all classes, except flavonols and isoflavones, showed significant inverse associations. A nonlinear association was found between flavonoid intake and CVD mortality in the dose–response analysis. For total mortality, a high intake of flavonoids was associated with lower total mortality (pooled RR = 0.86, 95% CI: 0.73, 1.00). Conclusions Our findings indicate that a high intake of flavonoids is associated with reduced risk of mortality from CVD and all causes in men and women. These results support current recommendations of high fruit and vegetables intake as a part of a healthy diet.