Although nutrients in fruit and vegetables have been associated with a reduced risk for coronary heart disease, good prospective studies have been lacking. After previously reporting the beneficial effects of fruit and vegetable intake on ischemic stroke risk, Joshipura and associates examined the relationship between fruit and vegetable intake and the development of coronary heart disease using data from two longitudinal, long-term follow-up studies, the Nurses' Health Study and the Health Professionals' Follow-up Study.
Diet questionnaires completed by all participants were reviewed, and the diet history of those who had either a myocardial infarction or a fatal coronary heart disease event during the study period were also collected. The questionnaires contained semiquantitative information about frequency of intake and portion size for specific fruits and vegetables. Quintiles were determined for the average daily fruit and vegetable intake, with the lowest quintile forming the baseline measure.
Participants who consumed a larger number of servings of fruit and vegetables had a lower risk of coronary heart disease. Adjusting for nondietary risk factors, study participants in the top quintile of intake had a risk for coronary heart disease that was 20 percent lower than the risk in the baseline group. Men and women had similar responses to higher intake of fruit and vegetables, with the greatest risk reduction occurring among participants who consumed more green leafy vegetables, cruciferous vegetables, and fruits and vegetables rich in vitamin C.
The authors conclude that while four servings per day of fruit and vegetables were associated with a slight drop in the risk of coronary heart disease, eight servings or more per day resulted in a significant risk reduction.