Protein is an essential component of the body. The organs, muscle, brain, nerves, and immune system are all, to some degree, comprised of protein. You name the body structure, and it probably has some protein in it. Since protein is one of the fundamental building blocks for the body, you need to ensure that you get enough in your diet.
Every protein molecule is composed of amino acids
. Twenty amino acids are used in different combinations to build the protein molecules found in food and in the body's structures. Nine of these amino acids are considered essential, and must be supplied through the diet. The other eleven amino acids (non-essential amino acids) can either be consumed in the diet or manufactured from other building blocks within the body.