by Lucia Stansbie
The building blocks of proteins. In nature there are around 100 amino acids, and the human body utilises 20 of them to build proteins. 9 of those amino acids are considered essential, meaning the body cannot synthesise them, either at all or in sufficient quantities, thus they must be supplied by our diet. The 9 essential amino acids are phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, histidine, leucine, and lysine.