Epidemiologic studies have suggested that higher intakes of fruit, vegetables, and whole grain are related to a lower risk of coronary heart disease (CHD). One explanation for this finding is a reduction in oxidatively modified LDL, which is thought to play an important role in the development of atherosclerosis. Whether the association between these foods and CHD is due to antioxidant vitamins or some other factors remains unclear.

In the present Pooling Project of Cohort Studies on Diet and Coronary Disease, the authors studied the relations of the intakes of vitamin E, five carotenoids, and vitamin C to the incidence of all major CHD events and CHD mortality by pooling primary data from nine major cohorts studies. This large database enabled several issues to be examined, such as whether 1) single antioxidants or combinations of them predict CHD occurrence, 2) the strength of associations differs by dietary and supplemental intake and 3) non-dietary or dietary risk factors of CHD modify the association.

During a 10-year follow-up, 4,647 major incident CHD events occurred in 293,172 subjects who were free of CHD at baseline. Diet was measured by using a food frequency questionnaire in seven cohorts and by using a dietary history interview or food records in two cohorts. Overall intakes (dietary and supplemental combined) of vitamin E, beta-carotene, total carotene, and vitamin C were calculated.