Nutrigenomics is a tool to measure gene expressions in response to dietary intake and better understand the human body's nutrient-gene interactions. Nutrigenetics is a tool to assess how genetic variations influence nutrients' interaction result of developing various chronic diseases. Dietary factors alter genes' expression, including nutritional factors such as antioxidants, vitamins, phytochemicals, caffeine, sterols, fatty acids, and alcohol. Furthermore, genetic polymorphisms in nutrient action targets such as enzymes could alter molecular pathways that influence the physiological response to dietary intake. Identifying relevant diet-gene interactions will benefit individuals seeking personalized nutritional advice.