Amino acids are organic compounds containing an amino group (NH2), a carboxylic group (COOH) and any of various side chain groups. There are twenty amino acids encoded by the genetic code, referred to as the standard amino acids. The basic components of proteins, amino acids form short polymers (meaning a long molecule made up of a chain of smaller, simpler molecules) called peptides or longer polymers called polypeptides or proteins. Additionally, amino acids can function as chemical messengers and as intermediates in metabolism.
The standard amino acids are classified as polar (meaning that one end of the molecule is more positively charged while the other is more negatively charged) and include Arginine, Asparagine, Aspartate, Glutamate, Glutamine, Histidine, Lysine, Serine, Threonine and Tyrosine; or nonpolar and include Alanine, Cysteine, Glycine, Isoleucine, Leucine, Methionine, Phenyalanine, Proline, Tryptophan and Valine.
Some of the twenty standard amino acids are called essential amino acids because the human body cannot synthesize them from other compounds through chemical reactions. Essential standard amino acids must be obtained from food and include Leucine, Isoleucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine and, in children, Arginine and Histidine.
Meat is animal tissue used as food, most often consisting of skeletal muscle and associated fat. While muscle tissue has a very high protein content and contains all of the essential amino acids, the essential amino acids can also be obtained from plant sources. However, Lysine and Tryptophan are poorly represented in plant proteins and strict vegetarians should ensure that their diet contains sufficient amounts of these two amino acids.
Amino acids are increasingly being used in everyday life. They are used in dietary sweeteners and anti-aging compounds. Amino acids are also used to help people sleep, overcome anxiety and depression and for treatment of medication overdose and liver detoxification. They have also been shown to have a beneficial role in the treatment of many diseases, including Alzheimer’s and cancer.