Non-essential amino acid

Nutritionally, amino acids are of two types: (a) Essential and (b) Non-essential. (c) There is also a third group of semi-essential amino acids. (a) Essential amino acids: These are the ones which are not synthesized by the body and must be taken in the diet. They include valine, leucine, isoleucine, phenylalanine, threonine, tryptophan, methionine and lysine. For remembering the following formula is used--MATT VIL PHLY. (b) Non-essential amino acids: They can be synthesized by the body and may not be the requisite components of the diet. (c) Semi-essential amino acids: These are growth promoting factors since they are not synthesized in sufficient quantity during growth. They include arginine and histidine. They become essential in growing children, pregnancy, and lactating women.Ref: Textbook of medical biochemistry, MN Chatterji, 8th edition, page no: 80