Protein is found throughout the bodyin muscle, bone, skin, hair, and virtually every other body part or tissue. It makes up the enzymes that power many chemical reactions and the hemoglobin that carries oxygen in your blood. At least 10,000 different proteins make you what you are and keep you that way.
Protein is made from twenty-plus basic building blocks called amino acids. Because we dont store amino acids, our bodies make them in two different ways: either from scratch, or by modifying others. Nine amino acidshistidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valineknown as the essential amino acids, must come from food.