The review discusses issues related to the importance of interaction between genetic and environmental factors for the implementation of the genetic program of individuals and determining the level of health. Data on the importance of some nutrients (vitamins, bio-elements) for formation of health, about a role of genetic factors in maintenance of a homeostasis of biologically active substances, about associations of the genes involved in a metabolism of nutrients with various pathologies, and examples of modification of effects of genetic polymorphic variants on risk of development of common diseases by various factors (bio-elements and other components of a diet, adverse factors of environment, drugs, etc.) are presented.