About 20 to 22 percent of the human body is made up of amino acids. They play a critical role in various metabolic activities of the body and form the fundamental structure of proteins. The human body needs around 22 different types of amino acids to perform a variety of bodily functions. Of these 10 are considered essential or indispensible (arginine and histidine are essential only for children) as they are not synthesized by the human body.
The eight essential amino acids namely tryptophan, leucin, isoleucin, valine, lysine, methionine, threonine, and phenylalanine need to be obtained from the food we eat or through supplements. These amino acids are vital for the smooth functioning of the immune system and for growth and maintenance of the lean body mass. They are also needed for the production of various enzymes and hormones. Methionine acts as a powerful antioxidant and helps in scavenging free radicals, while phenylalanine elevates the mood and promotes alertness and vitality.
The branched chain amino acids leucin, isoleucin, and valine help in maintaining normal blood glucose levels, heal muscle tissue, and fasten the recovery process following surgery. Other amino acids like alanine, arginine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine, hydroxylysine, and hydroxyproline, are called non-essential (or dispensable) amino acids as they are manufactured by the body. Even though they are not essential in diet, they are as important as the indispensable amino acids. They play an important role in regulating weight and in hemoglobin synthesis.
The non-essential amino acids ensure that the vitamins and minerals function properly and efficiently. They not only promote healthy brain function but also help in the synthesis of the gene molecules (DNA and RNA). In certain medical condition like sepsis and burns, dispensable amino acids like glutamine and arginine may become conditionally essential and promote wound healing. Cysteine and tyrosine are other conditionally essential amino acids that hasten the recovery process following injury.