Branched-Chain Amino Acids (BCAAs)
What do they do? Branched-chain amino acids (BCAAs) include leucine, isoleucine, and valine. BCAAs are needed for the maintenance of muscle tissue; they also are needed during times of physical stress and intense exercise. Research shows that BCAA supplements helps those with amyotrophic lateral sclerosis (Lou Gehrig’s disease) maintain muscle strength.1 In addition, individuals with liver disease (hepatic encephalopathy) benefit from intravenous administration of BCAAs.2
Where are they found? Dairy and red meat contain the greatest amount of BCAAs, although they are present in all protein—containing foods. Whey protein and egg protein supplements are other sources of BCAAs. BCAA supplements provide the single amino acids leucine, isoleucine, and valine.
In what conditions might BCAAs be supportive?
• post-surgery recovery
Who is likely to be deficient? Periods of physical stress, such as intense weight lifting and long—distance running, can create a catabolic state in which muscle tissue is broken down. In these situations, supplemental BCAAs—particularly leucine and its derivatives ketoisocaproate (KIC) and hydroxymethylbutyrate (HMB)—can be beneficial in reducing protein breakdown. Nonetheless, BCAA supplementation has not resulted in meaningful changes in body composition,3 nor does it improve exercise performance.4 5 6 During recovering from surgery, BCAA supplements may reduce muscle loss and speed muscle gain. BCAAs may also be useful to anyone wanting to prevent muscle breakdown.
How much should I take? A diet including animal protein provides an adequate amount of BCAA for most people. Athletes involved in intense training often take 5 grams of leucine, 4 grams of valine, and 2 grams of isoleucine per day to prevent muscle loss and increase muscle gain.
Are there any side effects or interactions? Side effects have not been reported with the use of BCAAs. A high intake of BCAAs are simply converted into other amino acids or used as energy.
It is prudent to take BCAAs along with whole proteins, such as lean meat or poultry, and multiple vitamins/minerals, especially the B-complex vitamins.
References:
1. Plaitakis A, Smith J, Mandeli J, et al. Pilot trial of branched-chain
amino acids in amyotrophic lateral sclerosis. Lancet May 7, 1988:1015-8.
2. Wahren J, Denis J, Desurmont P, et al. Is intravenous administration of branched chain
amino acids effective in the treatment of hepatic encephalopathy? A multicenter study. Hepatology
1983;3(4):475-80.
3. Kelly GS. Sports Nutrition: A review of selected nutritional supplements for
bodybuilders and strength athletes. Med Rev 1997;2:184-201.
4. MacLean DA, Graham TE, Satlin B. Branched-chain amino acids augment ammonia metabolism
while attenuating protein breakdown during exercise. Am J Physiol 1994;267:E1010-1022.
5. Blomstrand E, Hassmen P, Ek S, et al. Influence of ingesting a solution of
branched-chain amino acids on perceived exertion during exercise. Acta Physiol Scand
1997;159:41-49.
6. Van Hall G, Rasymakers JSH, Saris WHM, Wagenmakers AJM. Supplementation with
branched-chain amino acids (BCAA) and tryptophan has no effect on performance during
prolonged exercise. Clin Sci 1994;87:52 (abstract #75).
Copyright © 1998 Virtual Health, LLC
It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your physician, nutritionally-oriented health care practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.The information presented in HealthNotes Online is for informational purposes only.