ANTIOXIDANT MICRONUTRIENTS AND BREAST-CANCER

We reviewed epidemiologic evidence on the relationship between four an tioxidant micronutrients (vitamin A, vitamin C, vitamin E, and seleniu m) and breast cancer risk. Available data support a modest protective effect of vitamin A, although more studies are needed to examine furth er this association and to assess the relative contributions of prefor med vitamin A (retinol) and carotenoids. In addition, the possibility that some other component of vitamin A-rich foods may account for this observed association should be explored. Data on the relationship bet ween vitamins C and E and breast cancer risk are limited and inconsist ent, and further information is necessary. A substantial body of evide nce indicates a lack of any appreciable effect of selenium intake on b reast cancer risk, at least within the range of human diets. Future ob servational studies should ideally be prospective in design, as prospe ctive studies are less prone to selection and recall bias than are cas e-control studies, and should address methodologic issues such as conf ounding by other micronutrients and appropriate storage conditions of blood specimens. Although hypotheses relating micronutrient intake to risk of breast cancer should be tested in randomized trials, ethical a nd logistical constraints make these studies difficult to perform.