Vitamin E and breast cancer prevention: current status and future potential.

Vitamin E is a collective term used to refer to a number of structurally and functionally different compounds. Although some vitamin E compounds are popular supplements marketed for their potential beneficial antioxidant effects for a number of chronic diseases including various forms of cancer, a recent report by the National Academy of Sciences Food and Nutrition Board concluded that too little is known at present to provide definitive answers regarding whether taking larger doses of dietary antioxidants will help prevent chronic diseases. Recent reviews of epidemiological data suggest that dietary source vitamin E may provide some protection against breast cancer, while vitamin E supplements do not. A majority of studies investigating the protective effects of certain types of vitamin E in animal models of mammary cancer prevention conclude that there is little or no effect. The study of vitamin E is complex, and the vitamin E field faces many scientific challenges.