The role and metabolic functions of the branched-chain amino acids: a review

Abstract

In recent years, a number of new functions of branched-chain amino acids (BCAA) - leucine, valine and isoleucine - have been revealed in various states of the body in animals and humans. BCAA are involved in the regulation of the metabolism of not only proteins, but also lipids and carbohydrates, maintain the health of the mammary glands and intestines, and help in early implantation and development of embryos. BCAA increase protein synthesis and are currently considered as feed additives to improve meat productivity in pigs. New aspects of metabolic and regulatory functions of BCAA include a number of regularities: 1) insufficient or excessive levels of them in the diet enhances lipolysis; 2) BCAA, especially isoleucine, play an important role in glucose utilization by activating glucose transporters in the intestines and muscles; 3) BCAA enhance the development of the intestine, the transport of amino acids and the production of mucin; 4) BCAA are involved in the regulation of innate and adaptive immune responses. In the near future, the use of high-performance functional genomics, metabolomics, and proteomics will make it possible to more fully reveal the functions of BCAA in gene expression, protein synthesis, and metabolism regulation.