What is an essential amino acid?
Protein molecules are long chains of amino acids. There are 20 naturally occurring amino acids used in protein synthesis alanine, asparagine, aspartic acid, glutamic acid, cysteine, glutamine, glycine, proline, serine, tyrosine, arginine and histidine are non essential in that they can be sysnthesised from precursors in the diet. The amino acids isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine can not be synthesised by the body and therefore must be essential components of the diet. However some of the nonessential amino acids listed above are essential for normal growth in children since they do not have full biosynthetic capability as they develop. For a full explanation visit http://en.wikipedia.
