Nutritional biochemistry is one of the academic foundations that make up nutritional sciences, a discipline that encompasses the knowledge of nutrients and other food components with emphasis on their range of function and influence on mammalian physiology, health, and behavior. Nutritional biochemistry is a sub-discipline that is made up of the core knowledge, concepts, and methodology related to the chemical properties of nutrients and other dietary constituents and to their biochemical, metabolic, physiological, and epigenetic functions. A primary focus of research in nutritional biochemistry is the scientific establishment of optimal dietary intakes for every nutrient and food component throughout the life cycle. Nutritional bio-chemistry is rooted in analytical methodology that permits the purification of individual nutrients and the determination of their structures, as well as in classical biochemical approaches that identify metabolic pathways and elucidate the role of dietary components in regulating metabolism and gene expression.