This work is a review of epidemiologic data about the relationship between vitamin intake and cancer prevention. Observational studies have strongly suggested an inverse association between fruit and vegetable intake and cancer risk, and a protector effect of C and E vitamins and carotenoids against some kinds of cancer. In intervention trials beta-carotene was found to be deleterious to smokers, when supplemented in pharmacological doses isolated or associated with vitamin E or vitamin A. On the other hand, the consumption of antioxidants in physiological amounts may be effective against cancer, and this synergic action was observed in both in vivo model of carcinogenesis and epidemiologic intervention trial. It has been commended a generous daily consumption of fruits and vegetables, with amounts of C and E vitamins and carotenoids nearly to 150, 30, and 4 mg, respectively, and the vitamin supplements are not recommended as chemopreventive agents against cancer
nutritional epidemiology; chemoprevention; vitamins; neoplasms; antioxidants
