Clinical use of branched-chain amino acids in liver disease, sepsis, trauma, and burns.

The branched-chain amino acids (BCAAs)--leucine, isoleucine, and valine--share unique biochemical properties that may make them useful in altered physiologic states. They can be metabolized independently of liver function to provide energy, other amino acids, or small nitrogenous compounds. This unique ability makes the BCAAs a desirable supplement in liver disease with encephalopathy and, to a lesser extent, in sepsis with hepatic dysfunction. Furthermore, the BCAAs play a role in the regulation of protein synthesis, suggesting beneficial effects in catabolic states such as postoperative stress, trauma, renal failure, and burns. However, initial studies in these areas have presented equivocal results.