Nutrition is the science that studies the interactions between living organisms and food. Human nutrition includes the study of nutrients and other substances found in foods; how the human body uses nutrients for growth and maintenance; and the relationship between foods, food components, dietary patterns, and health. The study of nutrition encompasses all aspects of the ingestion, digestion, absorption, transport, metabolism, interaction, storage, and excretion of nutrients by the body. In a broader sense, the study of nutrition also includes the various psychological, sociological, cultural, technological, and economic factors that affect the foods and dietary patterns chosen by an individual.
Beth Fontenot, The Gale Group Inc., Macmillan Reference USA, New York,