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

Atherton, Philip J.; Kumar, Vinod; Selby, Anna L.; Rankin, Debbie; Hildebrandt, Wulf; Phillips, Bethan E.; Williams, John P.; Hiscock, Natalie; Smith, Kenneth

Abstract

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.

Citation

Atherton, P. J., Kumar, V., Selby, A. L., Rankin, D., Hildebrandt, W., Phillips, B. E., Williams, J. P., Hiscock, N., & Smith, K. (2017). Enriching a protein drink with leucine augments muscle protein synthesis after resistance exercise in young and older men. Clinical Nutrition, 36(3), 888-895. https://doi.org/10.1016/j.clnu.2016.04.025

• Journal Article Type: Article
• Acceptance Date: Apr 24, 2016
• Online Publication Date: Apr 30, 2016
• Publication Date: Jun 1, 2017
• Deposit Date: May 5, 2016
• Publicly Available Date: May 5, 2016
• Journal: Clinical Nutrition
• Print ISSN: 0261-5614
• Electronic ISSN: 1532-1983
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 36
• Issue: 3
• Pages: 888-895
• DOI: https://doi.org/10.1016/j.clnu.2016.04.025
• Keywords: Muscle; protein; nutrition; exercise; aging
• Public URL: https://nottingham-repository.worktribe.com/output/782953
• Publisher URL: http://dx.doi.org/10.1016/j.clnu.2016.04.025
• Additional Information: This article is maintained by: Elsevier; Article Title: Enriching a protein drink with leucine augments muscle protein synthesis after resistance exercise in young and older men; Journal Title: Clinical Nutrition; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.clnu.2016.04.025; Content Type: article; Copyright: © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
• Contract Date: May 5, 2016