Journal article
A protein-leucine supplement increases branched-chain amino acid and nitrogen turnover but not performance
Medicine and Science in Sports and Exercise, Vol.44(1), pp.57-68
2012
Abstract
PURPOSE: This study aimed to determine the effect of postexercise protein-leucine coingestion with CHO-lipid on subsequent high-intensity endurance performance and to investigate candidate mechanisms using stable isotope methods and metabolomics. METHODS: In this double-blind, randomized, crossover study, 12 male cyclists ingested a leucine/protein/CHO/fat supplement (LEUPRO 7.5/20/89/22 g• h -1, respectively) or isocaloric CHO/fat control (119/22 g• h -1) 1-3 h after exercise during a 6-d training block (intense intervals, recovery, repeated-sprint performance rides). Daily protein intake was clamped at 1.9 g• kg -1• d -1 (LEUPRO) and 1.5 g• kg -1• d -1 (control). Stable isotope infusions (1- 13C-leucine and 6,6- 2H 2-glucose), mass spectrometry-based metabolomics, and nitrogen balance methods were used to determine the effects of LEUPRO on whole-body branched-chain amino acid (BCAA) and glucose metabolism and protein turnover. RESULTS: After exercise, LEUPRO increased BCAA levels in plasma (2.6-fold; 90% confidence limits = ×/÷1.1) and urine (2.8-fold; ×/÷1.2) and increased products of BCAA metabolism plasma acylcarnitine C5 (3.0-fold; ×/÷0.9) and urinary leucine (3.6-fold; ×/÷1.3) and β-aminoisobutyrate (3.4-fold; ×/÷1.4) , indicating that ingesting ∼10 g leucine per hour during recovery exceeds the capacity to metabolize BCAA. Furthermore, LEUPRO increased leucine oxidation (5.6-fold; ×/÷1.1) and nonoxidative disposal (4.8-fold; ×/÷1.1) and left leucine balance positive relative to control. With the exception of day 1 (LEUPRO = 17±20 mg N• kg -1, control =-90±44 mg N• kg -1), subsequent (days 2-5) nitrogen balance was positive for both conditions (LEUPRO = 130±110 mg N• kg -1, control = 111±86 mg N• kg -1). Compared with control feeding, LEUPRO lowered the serum creatine kinase concentration by 21%-25% (90% confidence limits = ±14%), but the effect on sprint power was trivial (day 4 = 0.4%±1.0%, day 6 =-0.3%±1.0%). CONCLUSIONS: Postexercise protein-leucine supplementation saturates BCAA metabolism and attenuates tissue damage, but effects on subsequent intense endurance performance may be inconsequential under conditions of positive daily nitrogen balance.
Details
- Title
- A protein-leucine supplement increases branched-chain amino acid and nitrogen turnover but not performance
- Authors
- A R Nelson (Author) - Massey University, New ZealandS M Phillips (Author) - McMaster University, CanadaT Stellingwerff (Author) - Nestle Research Center, SwitzerlandS Rezzi (Author) - Nestle Research Center, SwitzerlandS J Bruce (Author) - Nestle Research Center, SwitzerlandI Breton (Author) - Nestle Research Center, SwitzerlandA Thorimbert (Author) - Nestle Research Center, SwitzerlandP A Guy (Author) - Nestle Research Center, SwitzerlandJ Clarke (Author) - Massey University, New ZealandSuzanne Broadbent (Author) - Southern Cross UniversityD S Rowlands (Author) - Massey University, New Zealand
- Publication details
- Medicine and Science in Sports and Exercise, Vol.44(1), pp.57-68
- Publisher
- Lippincott Williams & Wilkins
- Date published
- 2012
- DOI
- 10.1249/MSS.0b013e3182290371
- ISSN
- 0195-9131
- Organisation Unit
- University of the Sunshine Coast, Queensland; School of Health and Sport Sciences - Legacy; School of Health - Sports & Exercise Science; School of Health and Behavioural Sciences - Legacy
- Language
- English
- Record Identifier
- 99450325802621
- Output Type
- Journal article
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- Industry collaboration
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- Web Of Science research areas
- Sport Sciences