Amino acids
Chemical substances found in foods and produced by the body that are commonly called the building blocks of protein.

There are 21 amino acids, which are classified as either nonessential (ones the body can manufacture) or essential (ones which can only be derived from food).

Nonessential amino acids include alanine, argine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, taurine and tyrosine.

Essential amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.