Document Detail

Interrelationship between physical activity and branched-chain amino acids.
MedLine Citation:
PMID:  15930475     Owner:  NLM     Status:  MEDLINE    
Some athletes can have quite high intakes of branched-chain amino acids (BCAAs) because of their high energy and protein intakes and also because they consume protein supplements, solutions of protein hydrolysates, and free amino acids. The requirement for protein may actually be higher in endurance athletes than in sedentary individuals because some amino acids, including the BCAAs, are oxidized in increased amounts during exercise compared with rest, and they must therefore be replenished by the diet. In the late 1970s, BCAAs were suggested to be the third fuel for skeletal muscle after carbohydrate and fat. However, the majority of later studies, using various exercise and treatment designs and several forms of administration of BCAAs (infusion, oral, and with and without carbohydrates), have failed to find a performance-enhancing effect. No valid scientific evidence supports the commercial claims that orally ingested BCAAs have an anticatabolic effect during and after exercise in humans or that BCAA supplements may accelerate the repair of muscle damage after exercise. The recommended protein intakes for athletes (1.2 to 1.8 g . kg body mass(-1) . d(-1)) do not seem to be harmful. Acute intakes of BCAA supplements of about 10-30 g/d seem to be without ill effect. However, the suggested reasons for taking such supplements have not received much support from well-controlled scientific studies.
Michael Gleeson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  The Journal of nutrition     Volume:  135     ISSN:  0022-3166     ISO Abbreviation:  J. Nutr.     Publication Date:  2005 Jun 
Date Detail:
Created Date:  2005-06-02     Completed Date:  2005-07-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0404243     Medline TA:  J Nutr     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1591S-5S     Citation Subset:  IM    
School of Sport and Exercise Sciences, Loughborough University, Leicestershire, England, UK.
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MeSH Terms
Amino Acids, Branched-Chain / metabolism*
Dietary Proteins / administration & dosage,  metabolism*
Dietary Supplements
Energy Intake
Energy Metabolism*
Reg. No./Substance:
0/Amino Acids, Branched-Chain; 0/Dietary Proteins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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