Protein is the only nutrient that can build, repair, and maintain body tissues. An adequate supply of proteins in the daily diet is essential. All tissues and fluids in the body, with the exception of bile and urine, contain some protein.
Dead cells need to be replaced and damaged cells need to be repaired. As proteins form the basis for every body cell, it is obvious that the greatest need for protein is during growth stages such as infancy, childhood, adolescence, and pregnancy. Infants and children need the most protein in proportion to their size.
Proteins are made of amino acids, small units necessary for growth and tissue repair. Proteins are important in the development of skin, teeth, and bones. In addition, they build and repair damaged tissue and are important in enzyme and hormone production.