title: Effects of supplementation with branched chain amino acids and ornithine aspartate on plasma ammonia and central fatigue during exercise in healthy men.
abstract: BACKGROUND
  Our previous studies showed only slight improvement in central fatigue, measured indirectly by psychomotor performance, after branched chain amino acids (BCAA) supplementation during various efforts in healthy men. It is hypothesised that hyperammonaemia resulting from amino acids metabolism may attenuate their beneficial effect on psychomotor performance; therefore, the L-ornithine L-aspartate (OA) as an ammonia decreasing agent was used. The aim of this study was to investigate the effectiveness of oral BCAA + OA supplementation to reduce plasma ammonia concentration and enhance psychomotor performance during exhaustive exercise in healthy men.
  
  
  METHODS
  Eleven endurance-trained men (mean age 32.6 ± 1.9 years) performed two sessions (separated by one week) of submaximal cycloergometer exercise for 90 minutes at 60% of maximal oxygen uptake followed by graded exercise until exhaustion with randomised, double-blind supplementation with a total of 16 g BCAA and 12 g OA (BCAA + OA trial) or flavoured water (placebo trial). Before exercise, during both efforts and after 20 minutes of recovery multiple choice reaction time (MCRT), perceived exertion, heart rate and oxygen uptake were measured and venous blood samples were taken for plasma leucine, valine, isoleucine, ornithine, aspartate, free tryptophan (fTRP), ammonia, lactate and glucose determination.
  
  
  RESULTS
  After ingestion, during both efforts and after 20 minutes of recovery the plasma concentrations of all supplemented amino acids were significantly increased, while the fTRP/BCAA ratio decreased in the BCAA + OA trial more than in the placebo trial. At the end of graded exercise plasma fTRP was lower and MCRT shorter in BCAA + OA than in the placebo trial (p < 0.05). At the end of prolonged exercise the plasma ammonia concentration was higher in BCAA + OA than in placebo trial (p < 0.05). Decreases in plasma ammonia during recovery were significantly higher in BCAA + OA than in the placebo trial. Plasma ammonia positively correlated with the total plasma BCAA and MCRT only in the BCAA + OA trial. The fTRP/BCAA ratio positively correlated with MCRT only in the placebo trial.
  
  
  CONCLUSIONS
  Supplementation with BCAA and OA is a useful way to improve MCRT during high-intensity exercise and accelerate the elimination of ammonia at the recovery stage after exercise in healthy young men.
authors.affiliation: Tomasz Mikulski, Mossakowski Medical Research Centre, 5 Pawinskiego St., 02-106 Warszawa, Poland, phone: +48 22 608 65 17, fax: +48 22 668 54 45, e-mail: tomik@imdik.pan.pl.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Mikulski
authors.forename: Jan
authors.initials: J
authors.lastname: Dabrowski
authors.forename: Wojciech
authors.initials: W
authors.lastname: Hilgier
authors.forename: Andrzej
authors.initials: A
authors.lastname: Ziemba
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Krzeminski
mesh_terms: D000328:Adult; D000597:Amino Acids, Branched-Chain / Q000008:administration & dosage*; D000641:Ammonia / Q000097:blood*; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004151:Dipeptides / Q000008:administration & dosage*; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology; D006304:Health Status; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000187:drug effects* / Q000502:physiology; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology
chemical_list: D000597:Amino Acids, Branched-Chain; D004151:Dipeptides; D000641:Ammonia; C002939:ornithylaspartate