Fundamentals of Food Technology

Functions of the nutrients

Nutrients are components of food that are needed by the body in adequate amounts in order to grow, reproduce and lead a normal healthy life. Nutrients include water, proteins, fats, carbohydrates, minerals and vitamins.


Carbohydrates: The chief function is to provide energy. Those which are not used immediately for this purpose are stored as glycogen or converted to fat and stored, to be mobilized for energy supply when needed.

Proteins: The main function of protein is building of new tissues and maintenance and repair body tissues. Proteins are precursors of regulatory and protective substances such as enzymes, hormones and antibodies. About 10 per cent of the total energy is supplied by proteins, therefore it is the secondary function of proteins. Proteins in excess of requirement can be converted to carbohydrates or fats and stored.

Fats: Fats are concentrated sources of energy, carriers of fat-soluble vitamins and essential fatty acids. If excess fats are supplied in the diet, these may be stored as fat reserves in the body. When excess energy is supplied to the body, the carbohydrates, fats or proteins are stored as fat in the body.

Minerals: Functions include body-building (bones, teeth and structural parts of soft tissues) and regulation (e.g., muscle contraction).

Vitamins: Needed for growth and for regulation of body processes.

Water: An essential part of the body structure. It is a carrier of nutrients and a regulator of a number of body functions.

All individuals need the same nutrients for the body functions. The only variation is in the amounts of each nutrient required according to age, size, activity etc., For example, though all persons need energy for work, a man, who carries load (heavy worker) need more energy than a man who does desk job (sedentary worker).