Nutrition, Genetics, and Risks of Cancer

Dietary patterns, nutrients, and other constituents of food are major components of the environmental influences that contribute to risk for cancer, and the study of interactions between nutritional and genetic factors is a new and important area of research. This review describes the concepts and principles underlying this area of study and types of relationships between nutritional and genetic factors, and it provides examples of specific diet-gene interactions that are of current interest, with an emphasis on implications for cancer prevention and public health. Polymorphisms exist in the genes for the activating and conjugating metabolizing enzymes, and the induction of metabolizing enzyme activity by nutritional factors may result in either the activation of a carcinogen or the detoxification of a reactive intermediate metabolite. The relationship between the methylenetetrahydrofolate reductase gene and dietary folate is an example of a diet-gene interaction that involves a polymorphism in a vitamin metabolism gene, and the presence of the variant appears to influence both risk for cancer and folate requirements. Diet-gene interactions likely contribute considerably to the observed inter-individual variations in cancer risk in response to exposures to the nutritional factors that have the potential to promote or protect against cancer. Insights into mechanisms by which nutritional factors affect the process of carcinogenesis are provided by knowledge of the targeted gene function and enzyme activity. Increased knowledge in this area will allow a more refined approach to reducing risk for cancer, with diet interventions targeted toward individuals and subgroups that are genetically susceptible and responsive to the effects of nutritional factors.

Investigating the cellular and molecular pathogenesis of cancer is an established and important area of basic science research. Within the past several years, the capability of examining biomarkers of various genetic factors in the development and progression of chronic diseases, such as cancers, has enabled researchers to study these factors in clinical and community-based populations, in which environmental factors can also be measured or even manipulated. Dietary patterns and the nutrients and other co nstituents of food are a major component of the environmental influen ces that appear to contribute to disease risk, and the study of interactions between nutritional and genetic factors is a new and important area of research. This review describes the concepts and principles underlying this area of study, describes types of relationships between nutritional and genetic factors, provides examples of specific diet-gene interactions that are of current interest, and comments on implications for cancer prevention and public health.