Enriching a protein drink with leucine augments muscle protein synthesis after resistance exercise in young and older men

Atherton, Philip J. and Kumar, Vinod and Selby, Anna L. and Rankin, Debbie and Hildebrandt, Wulf and Phillips, Bethan E. and Williams, John P. and Hiscock, Natalie and Smith, Kenneth (2016) Enriching a protein drink with leucine augments muscle protein synthesis after resistance exercise in young and older men. Clinical Nutrition . ISSN 0261-5614

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Maximizing anabolic responses to feeding and exercise is crucial for muscle maintenance and adaptation to exercise training. We hypothesized that enriching a protein drink with leucine would improve anabolic responses to resistance exercise (RE: 6×8 knee-extension repetitions at 75% of 1-RM) in both young and older adults. Groups (n=9) of young (24±6 y, BMI 23±2kg.m-2) and older men (70±5 y, BMI 25±2 kg.m-2) were randomized to either: (i) RE followed by Slim-Fast Optima (SFO 10 g PRO; 24 g CHO) with 4.2 g of leucine (LEU) or, (ii) RE+SFO with 4.2 g of alanine (ALA; isonitrogenous control). Muscle biopsies were taken before, immediately after, and 1, 2 and 4 h after RE and feeding. Muscle protein synthesis (MPS) was measured by incorporation of [1, 2-13C2] leucine into myofibrillar proteins and the phosphorylation of p70S6K1 by immunoblotting. In young men, both area under the curve (AUC; FSR 0-4 h P<0.05) and peak FSR (0.11 vs. 0.08%.h.-1; P<0.05) were greater in the SFO+LEU than in the SFO+ALA group, after RE. Similarly, in older men, AUC analysis revealed that post-exercise anabolic responses were greater in the SFO+LEU than SFO+ALA group, after RE (AUC; FSR 0-4 h P<0.05). Irrespective of age, increases in p70S6K1 phosphorylation were evident in response to both SFO+LEU and SFO+ALA, although greater with leucine supplementation than alanine (fold-change 2.2 vs. 3.2; P<0.05), specifically in the older men. We conclude that addition of Leucine to a sub-maximal PRO bolus improves anabolic responses to RE in young and older men.

Item Type: Article
Keywords: Muscle; protein; nutrition; exercise; aging
Schools/Departments: University of Nottingham UK Campus > Faculty of Medicine and Health Sciences > School of Medicine
Identification Number: https://doi.org/10.1016/j.clnu.2016.04.025
Depositing User: Eprints, Support
Date Deposited: 05 May 2016 16:48
Last Modified: 14 Sep 2016 10:05
URI: http://eprints.nottingham.ac.uk/id/eprint/33108

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