Vitamin intake and risk of coronary disease: observation versus intervention

The evidence that specific vitamins may be beneficial in the prevention of cardiovascular disease (CVD) is supported by mechanistic models of atherogenesis. We and others have published observational epidemiologic studies in support of vitamins in the primary prevention of CVD, but the results from intervention studies are mixed. This article summarizes the recent results for vitamin E, vitamin D, and the B vitamins, comparing study populations, study designs, and potential methodologic reasons for differences in findings. For vitamin E, observational data suggest benefit at doses of 100 to 400 IU/d. Results from recent large-scale trials are mixed, with some showing modest benefit but others suggesting no benefit, especially for secondary prevention. Results for B vitamins are also mixed and further complicated by the recent folate fortification of the flour supply. If greater B vitamin intake does reduce CVD, the benefits are likely to be greatest for primary prevention and in populations with intake below dietary reference standards. Research on vitamin D and CVD is just beginning to emerge, but current data suggest that if there is benefit it likely needs to be at intake levels much higher than the current reference intakes of 200 to 600 IU/d for American adults.