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Branched-Chain Amino Acids

What Should I Know About Them?

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Updated January 07, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Branched-chain amino acids are a type of essential amino acid involved in the body's production of protein. Available in a number of foods (including meat, dairy products, and legumes), branched-chain amino acids include valine, leucine, and isoleucine. Said to offer a variety of health benefits and improve athletic performance, branched-chain amino acids are also sold in supplement form.

Uses for Branched-Chain Amino Acids

In addition to enhancing athletic performance, branched-chain amino acids are said to help treat or prevent the following health conditions:

Branched-chain amino acids are also used to prevent fatigue, improve brain function and concentration, promote weight loss, and stimulate appetite in people undergoing treatment for cancer.

Benefits Of Branched-Chain Amino Acids

A number of scientific studies indicate that use of supplements containing branched-chain amino acids may offer certain health benefits. Here's a look at some key findings from the available research:

1) Liver Disease

Branched-chain amino acids may be of some benefit to people with liver disease, according to a 2011 study published in the Journal of Cellular Biochemistry. In tests on rats, researchers found that branched-amino acids may help protect against abnormalities in blood sugar metabolism commonly associated with cirrhosis (a disease marked by scarring of the liver).

2) Exercise Performance

Several studies suggest that use of branched-chain amino acids may impact exercise performance. In a 2006 report published in the Journal of Nutrition, for instance, researchers analyzed the available research on the use of branched-chain amino acids and found that the supplements may help improve physical performance and prevent fatigue during long periods of exercise.

There's also some evidence that branched-chain amino acids may help promote muscle recovery and decrease soreness after exercise. For example, a 2007 study published in the Journal of Sports Medicine and Physical Fitness found that consumption of a drink containing branched-chain amino acids helped to lessen the degree of muscle damage in long-distance runners. In an experiment involving eight male runners, the study's authors found that the branched-chain-amino-acid-enriched drink was more effective than a placebo drink in reducing the release of lactate dehydrogenase (a marker of tissue damage) during a 25-kilometer run.

Safety

Although supplements containing branched-chain amino acids are generally safe when used in the short term (six months or less), they may trigger several side effects, such as fatigue and loss of motor coordination.

It's important to note that self-treating a chronic condition with branched-chain amino acids, and avoiding or delaying standard care, may have serious consequences. If you're considering the use of branched-chain amino acids in treatment of a chronic condition, make sure to consult your physician before starting your supplement regimen.

Where To Find Branched-Chain Amino Acids

Widely available for purchase online, branched-chain amino acids are sold in many natural-foods stores and in stores specializing in dietary supplements.

Sources

Bianchi G, Marzocchi R, Agostini F, Marchesini G. "Update on nutritional supplementation with branched-chain amino acids." Curr Opin Clin Nutr Metab Care. 2005 Jan;8(1):83-7.

Blomstrand E. "A role for branched-chain amino acids in reducing central fatigue." J Nutr. 2006 Feb;136(2):544S-547S.

Blomstrand E, Eliasson J, Karlsson HK, Köhnke R. "Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise." J Nutr. 2006 Jan;136(1 Suppl):269S-73S.

Higuchi N, Kato M, Miyazaki M, Tanaka M, Kohjima M, Ito T, Nakamuta M, Enjoji M, Kotoh K, Takayanagi R. "Potential role of branched-chain amino acids in glucose metabolism through the accelerated induction of the glucose-sensing apparatus in the liver." J Cell Biochem. 2011 Jan;112(1):30-8.

Koba T, Hamada K, Sakurai M, Matsumoto K, Hayase H, Imaizumi K, Tsujimoto H, Mitsuzono R. "Branched-chain amino acids supplementation attenuates the accumulation of blood lactate dehydrogenase during distance running." J Sports Med Phys Fitness. 2007 Sep;47(3):316-22.

Negro M, Giardina S, Marzani B, Marzatico F. "Branched-chain amino acid supplementation does not enhance athletic performance but affects muscle recovery and the immune system." J Sports Med Phys Fitness. 2008 Sep;48(3):347-51.

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