Nutrient

A nutrient is either a chemical element or compound used in an organism's metabolism or physiology. A nutrient is essential to an organism if it cannot be produced by the organism and must be obtained from a food source.^[1]

This article deals with nutrition in animals, especially humans. Nutrition in plants, fungi, bacteria and archaea is not discussed here.

1. ↑ Sizer F. & Whitney E. 2007. Nutrition: concepts and controversies. Belmont CA: Thompson Wadworth.