What is a Nutrient ?

A nutrient is a substance that promotes body growth or improvement or repairs the natural waste of the body. You need more than 40 different nutrients for good health. These include:
Energy sources (measured in calories)

Carbohydrates (starches, sugars)
Fats
Proteins
Vitamins
Minerals
Amino acids (from proteins)
Essential fatty acids (from fats and oils)
Water

CARBOHYDRATES:

Iinclude starches, sugars, and dietary fiber. Starches and sugar supply the body with energy. Dietary fiber provides bulk in the diet, which encourages regular elimination of wastes.

FATS :

Provide energy and are carriers of fat-soluble vitamins. Fats also add flavor to foods. Some fats help form cell membranes and hormones.

PROTEINS:

Are the building blocks of the body. They are needed for growth, maintenance, and replacement of body cells. They also form the hormones and enzymes used to regulate body processes. Any extra protein is used to supply energy or is changed into body fat (stored energy).

VITAMINS:

Are organic substances needed by the body in small amounts. They do not supply energy, but they help release energy from carbohydrates, fats, and protein. They also help in other chemical reactions in the body.

MINERALS:

Are also needed in relatively small amounts and do not supply energy. They are used to build strong bones and teeth, and to make hemoglobin in red blood cells. They help maintain body fluids and help in other chemical reactions in the body.

WATER :

Is often called the "forgotten nutrient." It is needed to replace body water lost in urine and sweat. Water helps to transport nutrients, remove wastes, and regulate body temperature.