Essential amino acids are those one cannot manufacture, because the body lack the enzymes necessary to create them from other biological molecules, thus they must be supplied from the diet each day. They include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Anorexia is a characteristic phenomenon that is induced by many types of dietary essential amino acid deficiencies . A valine deficiency for example is one of the strongest inducers of anorexia among deficiencies of the 9 essential amino acids.
