Dietary flavonoids and the development of type 2 diabetes and cardiovascular diseases: review of recent findings

Purpose of review This review summarizes the results on flavonoid intakes and the development of type 2 diabetes and cardiovascular diseases. Recent findings Recent advances in food composition databases have allowed the evaluation of a more comprehensive range of flavonoids in epidemiological studies. In addition, the number of randomized trials of flavonoid-rich foods has increased rapidly. Results from both cohort studies and randomized trials suggest that anthocyanidins from berries and flavan-3-ols from green tea and cocoa may lower the risk of type 2 diabetes and cardiovascular diseases. Meta-analyses of randomized trials indicate that the strongest evidence exists for a beneficial effect of green tea on LDL-cholesterol and a beneficial effect of flavan-3-olrich cocoa on endothelial function and insulin sensitivity. Few randomized trials had a long duration or evaluated pure flavonoid compounds. Summary Evidence from cohort studies and randomized trials suggest beneficial effects of food sources of anthocyanidins (berries) and flavan-3-ols (green tea and cocoa) on cardiovascular health. These findings need to be confirmed in long-term randomized trials, and evaluation of pure compounds will be important to establish what specific flavonoids and doses are effective.