Gene-nutrient interactions in nutritional epidemiology

There is increasing evidence that the ways in which nutrients are handled metabolically is, to a greater or lesser extent, under genetic control. Equally, nutrient (and non-nutrient) intakes affect the expression of genetic predispositions. These complex interactions (nutrient regulation of gene transcription, food-induced DNA damage, phytochemical enhancement or protection of DNA integrity, genetic susceptibility to nutrition-related diseases) increasingly shed light on epidemiological relationships between diet and health and disease. This chapter considers design and analytical implications for understanding gene-nutrient interactions, including specific statistical models. It concludes with a discussion of ethical issues, and an appendix for sample size determination in relation to the determination of genetic characteristics in nutritional epidemiological studies.