Introduction:
Branched chain amino acids (leucine, isoleucine, valine) are mainly constituents of proteins, but also regulate many physiological processes in the human body. The aim of this study was to analyze the current state of knowledge about the importance of BCAA in human beings, their use in the nutrition of the healthy and sick, and in the prevention of some diseases. Adult needs for leucine, valine and isoleucine are, respectively: 40, 17–25, 19 mg / kg body weight. Deficiencies in the intake of BCAA’s are rare and concerns groups consuming inadequate amounts of protein in the diet, and those suffering from kidney and liver diseases in which protein metabolism is disturbed. The available data show that doses of two or even three times higher than those recommended are well tolerated and do not cause any side effects. A sufficiently high concentration of branched chain amino acids in the blood is a factor in the limited uptake of tryptophan, tyrosine and phenylalanine to the brain. This property is used in the treatment of several diseases, such as cirrhosis and hepatic encephalopathy, phenylketonuria, bipolar disorder, tardive dyskinesia and cachexia syndrome. Branched chain amino acids, in addition to their constituent function, also play a regulatory role in the effect on the secretion of hormones and catecholamines, the formation of neurotransmitters, and stimulation of protein synthesis. They can be a source of energy, influence wellbeing, reduce physical fatigue. They are a substrate for the synthesis of other amino acids and are an important factor in the treatment of certain diseases.