When scientist began mapping the human genome in the 90s, it was thought an individual's disease risk was determined based on their genetic makeup. However, it was found the expression of a gene is predominantly determined by various environmental factors such as nutrition. This gave rise to the study of epigenetics where we examine how the environment influences gene expression. These factors do not directly alter the DNA but effect whether or not the genes are turned on or off. The Greek root epi- means “in addition to” or “on top of”, therefore epigenetics examines factors that are “in addition to” our traditional genetic basis for inheritance.
The field of science that is researching the connection between nutrition, genetics and disease outcome is Nutritional Genomics. Within Nutritional Genomics, we examine how dietary factors influence gene expression and how genes effect nutritional status and health outcomes.