Selenium and vitamins A, E, and C: nutrients with cancer prevention properties.

It has been estimated that 35% of all cancer incidence is related to diet. The potential appears great that high intakes of various nutrients can reduce the incidence of some types of cancer. Selenium and vitamins A, C, and E, discussed in this article, have many actions and interactions that are important in relationship to the study of nutrition and cancer. Even though only a few of the necessary human trials of efficacy have been conducted, epidemiological and animal data suggest that vitamins and/or minerals act as anticarcinogens, altering cancer incidence, differentiation, and growth. Thus, they may prove useful adjuncts to conventional therapies or in cancer prevention. However, the nutrients should not be viewed as cure-alls that work alone. Adequate intake ideally should be the result of increased dietary consumption rather than supplements because as yet unidentified components found in food may prove beneficial and protective. More research is needed prior to encouraging members of the general population to increase their intakes of various nutrients, even though there is now some evidence that those nutrients may help prevent some cancers.