Fruit and vegetable consumption and risk of coronary heart disease: a meta-analysis of cohort studies

Abstract

The consumption of fruit and vegetables is associated with a reduced rate of coronary heart disease (CHD) in observational cohorts. The purpose of this study was to assess the strength of this association in a meta-analysis. Cohort studies were selected if they reported relative risks (RRs) and 95% CI for coronary heart disease or mortality and if they presented a quantitative assessment of fruit and vegetable intake. The pooled RRs were calculated for each additional portion of fruit and/or vegetables consumed per day, and the linearity of the associations were examined. Nine studies were eligible for inclusion in the meta-analysis that consisted of 91,379 men, 129,701 women, and 5,007 CHD events. The risk of CHD was decreased by 4% [RR (95% CI): 0.96 (0.93-0.99), P = 0.0027] for each additional portion per day of fruit and vegetable intake and by 7% [0.93 (0.89-0.96), P < 0.0001] for fruit intake. The association between vegetable intake and CHD risk was heterogeneous (P = 0.0043), more marked for cardiovascular mortality [0.74 (0.75-0.84), P < 0.0001] than for fatal and nonfatal myocardial infarction [0.95 (0.92-0.99), P = 0.0058]. Visual inspection of the funnel plot suggested a publication bias, although not statistically significant. Therefore, the reported RRs are probably overestimated. This meta-analysis of cohort studies shows that fruit and vegetable consumption is inversely associated with the risk of CHD. The causal mechanism of this association, however, remains to be demonstrated.