Flavonoid intake and cardiovascular disease mortality: a prospective study in postmenopausal women

BACKGROUND: Dietary flavonoids may have beneficial cardiovascular effects in human populations, but epidemiologic study results have not been conclusive. OBJECTIVE: We used flavonoid food composition data from 3 recently available US Department of Agriculture databases to improve estimates of dietary flavonoid intake and to evaluate the association between flavonoid intake and cardiovascular disease (CVD) mortality. DESIGN: Study participants were 34 489 postmenopausal women in the Iowa Women's Health Study who were free of CVD and had complete food-frequency questionnaire information at baseline. Intakes of total flavonoids and 7 subclasses were categorized into quintiles, and food sources were grouped into frequency categories. Proportional hazards rate ratios (RR) were computed for CVD, coronary heart disease (CHD), stroke, and total mortality after 16 y of follow-up. RESULTS: After multivariate adjustment, significant inverse associations were observed between anthocyanidins and CHD, CVD, and total mortality [RR (95% CI) for any versus no intake: 0.88 (0.78, 0.99), 0.91 (0.83, 0.99), and 0.90 (0.86, 0.95)]; between flavanones and CHD [RR for highest quintile versus lowest: 0.78 (0.65, 0.94)]; and between flavones and total mortality [RR for highest quintile versus lowest: 0.88 (0.82, 0.96)]. No association was found between flavonoid intake and stroke mortality. Individual flavonoid-rich foods associated with significant mortality reduction included bran (added to foods; associated with stroke and CVD); apples or pears or both and red wine (associated with CHD and CVD); grapefruit (associated with CHD); strawberries (associated with CVD); and chocolate (associated with CVD). CONCLUSION: Dietary intakes of flavanones, anthocyanidins, and certain foods rich in flavonoids were associated with reduced risk of death due to CHD, CVD, and all causes.