Double-blind, placebo-controlled pilot trial of L-Leucine-enriched amino-acid mixtures on body composition and physical performance in men and women aged 65–75 years

Ispoglou, T., White, H., Preston, T. , McElhone, S., McKenna, J. and Hind, K. (2016) Double-blind, placebo-controlled pilot trial of L-Leucine-enriched amino-acid mixtures on body composition and physical performance in men and women aged 65–75 years. European Journal of Clinical Nutrition, 70(2), pp. 182-188. (doi: 10.1038/ejcn.2015.91) (PMID:26081485) (PMCID:PMC4744242)

Abstract

Background/Objectives: Adequate protein intake is essential to retaining muscle and maintaining physical function, especially in the elderly, and L-Leucine has received attention as an essential amino acid (EAA) that enhances protein retention. The study’s aim was to compare the efficacy of EAA mixtures on lean tissue mass (LTM) and functional performance (FP) in a healthy elderly population. Subjects/Methods: Thirty-six subjects (65–75 years) volunteered to receive capsules with EAAs (Groups A and B containing 20% and 40% L-Leucine, respectively) or placebo (lactose containing 0% L-Leucine, Group C) for 12 weeks. The daily amount ranged from 11 to 21 g (0.21 g/ kg/day) and was taken in two equal dosages alongside food, morning and evening. Main outcomes measured before and after intervention were LTM and FP (30-s arm-curl test; 30-s chair-stand test (30-CST); 6-min walk test (6-WT); and handgrip strength). Secondary outcomes included dietary intakes and physical activity. Results: Twenty-five subjects (11 male and 14 female) completed the study (Group A, n=8; Group B, n=8; Group C, n=9). Gains associated with medium effect sizes were noted in LTM (Group B, 1.1 ±1.1%, P=0.003) and FP (Group A in 30-CST (11.0±11.5%, P=0.02) and 6-WT (8.8±10.0%, P=0.02); Group B in 6-WT (5.8±6.6%, P=0.03) and a trend in 30-CST (13.2±16.0, P=0.06)). Significant differences between groups were not observed in secondary outcomes. Conclusions: Twice-daily supplementation of EAAs containing 20% or 40% L-Leucine improved aspects of functional status and at the higher level improved LTM. Further work to establish change in a larger sample and palatable supplemental format is now required.

• Item Type: Articles
• Additional Information: The study was supported by an institutional grant. We thank all subjects for their time, effort and dedication. Special thanks to the Faculty learning support officers.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Preston, Professor Tom
• Authors: Ispoglou, T., White, H., Preston, T., McElhone, S., McKenna, J., and Hind, K.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: European Journal of Clinical Nutrition
• Publisher: Nature Publishing Group
• ISSN: 0954-3007
• ISSN (Online): 1476-5640
• Published Online: 17 June 2015
• Copyright Holders: Copyright © 2016 The Authors
• First Published: First published in European Journal of Clinical Nutrition 70(2): 182-188
• Publisher Policy: Reproduced under a Creative Commons License