BCAA stands for branched chain amino acids and is increasingly being recognized as an important supplement in the field of sports nutrition. In short the term refers to three essential amino acids - leucine, isoleucine and valine. Amino acids are widely known as the building blocks of protein. When protein food is eaten it gets digested into individual amino acids and short chains of amino acids that are sufficiently small to be absorbed into the bloodstream. They are then used by the body to .