Branched chain amino acids are required for protein synthesis, and repair and maintenance of the muscle tissues. Branched-chain amino acid (BCAA) is the name given to three of the eight essential amino acids needed to make protein: leucine, isoleucine and valine. Approximately one-third of skeletal muscle in the human body is made up by a combination of these three essential amino acids. When there are not enough branched chain amino acids in the body, our body breaks down the muscles to get them. This can happen during exercise and periods of extreme stress.
BCCAs promote muscle nitrogen, enhances glutamine production, decreases lactate production and boosts energy while reducing protein and muscle breakdown during intense exercise. In endurance athletes, these actions help to sustain muscle work capacity and muscle recovery. Studies have demonstrated that post-exercise protein intake helps enhance the repair of muscle protein. There is also some reports that suggest that BCAAs may also moderate the progression of central nervous system fatigue during exercise supporting mental performance.*
Each branched chained amino acids performs a specific function. For example, leucine plays a crucial role in insulin secretion, healing of muscle tissues, skin and bones. Leucine also works in conjunction with the other two BCAAs to protect muscle and act as fuel for the body. Isoleucine stabilizes and regulates blood sugar and energy levels. It is also needed for hemoglobin formation. Valine facilitates muscle metabolism and repair of tissues, as well as, maintaining the proper balance of nitrogen in the body.
When coupled together these BCCAs enhance energy, increase endurance and aid in the healing and repair of muscle tissue, making them a valuable tool for athletes. It is recommended that supplemental isoleucine should always be taken with a correct balance of the other two branched-chain amino acids; approximately two milligrams each of leucine and valine for each milligram of isoleucine. 2:1:1
*Newsholme EA, Blomstrand E, Ekblom B. Physical and mental fatigue: metabolic mechanisms and importance of plasma amino acids. Br Med Bull 1992;48(3):477-95