Protein can be found almost anywhere in the body, it is used to make cells. It is the main component of muscles, organs, and glands. Every living cell and all body fluids, except bile and urine, contain protein.

After foods have entered the body they are digested, and the amino acids become free, to be used by our bodies to make the necessary proteins. These are required for growth and development; for making new cell substances such as protoplasm, but also for making antibodies, enzymes, hormones, etc. Proteins serve also as an energy source.