Nutrition: the study of the nutrients in foods and in the body; sometimes also the study of human behaviors related to food.
Nutrients: components of food that are indispensable to the body's functioning. They provide energy, serve as building material, help maintain or repair body parts, and support growth. The nutrients include water, carbohydrates, protein, fat, vitamins and minerals.
(Nutrition Concepts and Controversies by Frances Sizer and Ellie Whitney; Pg. GL-15)