Nine essential amino acids (the components of proteins) must be obtained through diet, because they are not made naturally within the body. Three of these nine essential amino acids are isoleucine, leucine, and valine, all of which feature a branching molecular structure. These are call branch-chain amino acids (BCAA).
Nine essential amino acids (the components of proteins) must be obtained through diet, because they are not made naturally within the body.
Three of these nine essential amino acids are isoleucine, leucine, and valine, all of which feature a branching molecular structure. These are call branch-chain amino acids (BCAA).
Other amino acids are metabolized in the liver, while BCAA are metabolized in lean body mass tissue. Because of BCAA presence in lean body mass tissue, BCAA supplementation may contribute to exercise performance and they may prevent the breakdown of these tissues.
Supplementation may also boost lean body mass in individuals on a low protein diet. In one study, leucine and valine were found to suppress body weight loss in mice with cachexia. Both of these BCAAs increased muscle tissue through an increase in protein synthesis reduced degradation.
BCAA supplementation may also prevent fatigue in athletes by halting the decline in serum BCAA levels which occurs during exertion. A decline in serum BCAA levels may release tryptophan into the brain, which is followed by increased serotonin production and consequent fatigue.
The amino acid leucine provides critical support for the synthesis of muscle protein. Isoleucine also plays a key role by causing cells to store more glycogen. Valine functions synergistically with the other two BCAA, to boost growth, repair tissues, regulate blood sugar, and energize the body. Valine also stimulates the central nervous system which supports mental function.
Isoleucine is the BCAA best known for its role in increasing endurance, repairing lean tissue, and stimulating blood clotting after an injury. Isoleucine has been shown to benefit athletes by increasing energy and supporting recovery from strenuous activity.
An isoleucine deficiency may present in fashion similar to hypoglycemia, which can include headaches, dizziness, fatigue, depression, confusion, and irritability.
Leucine: Leucine joins with the other BCAAs to repair lean mass, regulate blood sugar, and maintain energy levels. L-leucine can also temporarily increase the production of growth hormone.
Leucine is metabolized to glucose more quickly than isoleucine or valine. Increased glucose availability prevents the body from breaking down lean body mass during intense exertion. Leucine is also involved in the healing of bones, skin, and lean tissue after injury. Because of this leucine is often part of nutritional support for people recovering from surgery.
Valine: Valine may help remove excess nitrogen from the liver and transport nitrogen as needed to other tissues in the body. Valine may also provide nutritional support in people with liver and gallbladder disease caused by alcoholism or drug abuse. This amino acid has also been studied for its potential to reverse alcohol-related brain damage.
Daily intake of BCAA supplements—amounts in excess of those found in dietary sources-- appears to be safe, though excessive oral consumption can cause gastrointestinal discomfort.
BCAA injections should not be taken by patients with Maple Sugar Urine disease. BCAA injections in people with ALS (Lou Gehrig’s Disease) have been linked to lung failure and increased death rates.