nutrition

Strategy adopted by an organism to obtain the chemicals it needs to live, grow, and reproduce. These chemicals are nutrients that are absorbed from the environment, such as mineral salts, or chemicals made inside the body of a plant or animal. Nutrition is a term also used to describe the science of food, and its effect on human and animal life, health, and disease. Nutrition involves the study of the basic nutrients required to sustain life, their bioavailability in foods and overall diet, and the effects upon them of cooking and storage. It is also concerned with dietary deficiency diseases.

Plant nutrition is very different from animal nutrition in several ways. In a plant high-energy food (for example, carbohydrate) is made inside the plant by photosynthesis. An animal obtains high-energy food by eating a plant or another animal. Nutrients from the environment are absorbed by different parts of plant and animal bodies. In a plant, nutrients are absorbed from soil water by the roots (see root hair cell). In an animal, nutrients are absorbed from the gut by the epithelium cells lining it.