The human body needs protein to function well. Proteins are used to build and repair tissues, and they are also used by the body to make enzymes, hormones and other such chemicals. Protein is an important building block of muscles, skin, bones, cartilage, blood and hair.
Protein is essential in the human diet as the body is not capable of making all types of protein. While some proteins can be made by the liver, other proteins must be acquired through diet. Proteins can be included in the diet either through plant-based food sources such as soy, nuts and beans or through animal-based food sources such as fish, dairy and eggs.