Fruits and vegetables in the prevention of cancer and cardiovascular disease.

OBJECTIVE We quantified the public health benefit of fruits and vegetables on the prevention of cancer and cardiovascular disease (CVD), using currently available human data. DESIGN We reviewed over 250 observational studies on cancer and CVD. Relative risks (RRs) for high versus low intake of fruits and vegetables were obtained. The preventable proportion of chronic diseases, i.e. the per cent of cases attributable to low consumption of fruits and vegetables, was estimated using three scenarios: best guess, optimistic (using stronger RRs) and conservative (using weaker RRs and eliminating the contribution of smoking and/or drinking). The preventable proportion was calculated for increasing average intake from the current 250 g day(-1) to the recommended 400 g day(-1) among the general Dutch population. RESULTS It is estimated that in the Netherlands cancer incidence could be reduced by 19% (12,000 cases annually, best guess), ranging from 6% (conservative) to 28% (optimistic). Cardiovascular deaths could be reduced by 16% (8000 deaths annually, best guess), ranging from 6% to 22%. Evidence is most abundant for gastrointestinal cancers, followed by hormone-related cancers, but limited for other sites and CVD. CONCLUSIONS Increasing consumption of fruits and vegetables carries a large public health potential. Population trials and biological mechanisms should eventually provide scientific proof of their efficacy. The available evidence is sufficient to justify public health education and promotion aimed at a substantial increase in the consumption of fruits and vegetables.