Leucine Supplementation Does Not Attenuate Skeletal Muscle Loss during Leg Immobilization in Healthy, Young Men

Evelien M. P. Backx, Astrid M. H. Horstman, Gabriel N. Marzuca-Nassr, Janneau van Kranenburg, Joey S. Smeets, Cas J. Fuchs, Anniek A. W. Janssen, Lisette C. P. G. M. de Groot, Tim Snijders, Lex B. Verdijk, Luc J. C. van Loon*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

23 Citations (Web of Science)

Abstract

Background: Short successive periods of physical inactivity occur throughout life and contribute considerably to the age-related loss of skeletal muscle mass. The maintenance of muscle mass during brief periods of disuse is required to prevent functional decline and maintain metabolic health. Objective: To assess whether daily leucine supplementation during a short period of disuse can attenuate subsequent muscle loss in vivo in humans. Methods: Thirty healthy (22 +/- 1 y) young males were exposed to a 7-day unilateral knee immobilization intervention by means of a full leg cast with (LEU, n = 15) or without (CON, n = 15) daily leucine supplementation (2.5 g leucine, three times daily). Prior to and directly after immobilization, quadriceps muscle cross-sectional area (computed tomography (CT) scan) and leg strength (one-repetition maximum (1-RM)) were assessed. Furthermore, muscle biopsies were taken in both groups before and after immobilization to assess changes in type I and type II muscle fiber CSA. Results: Quadriceps muscle cross-sectional area (CSA) declined in the CON and LEU groups (p <0.01), with no differences between the two groups (from 7712 +/- 324 to 7287 +/- 305 mm(2) and from 7643 +/- 317 to 7164 +/- 328 mm(2); p = 0.61, respectively). Leg muscle strength decreased from 56 +/- 4 to 53 +/- 4 kg in the CON group and from 63 +/- 3 to 55 +/- 2 kg in the LEU group (main effect of time p <0.01), with no differences between the groups (p = 0.052). Type I and II muscle fiber size did not change significantly over time, in both groups (p > 0.05). Conclusions: Free leucine supplementation with each of the three main meals (7.5 g/d) does not attenuate the decline of muscle mass and strength during a 7-day limb immobilization intervention.

Original languageEnglish
Article number635
Number of pages12
JournalNutrients
Volume10
Issue number5
DOIs
Publication statusPublished - May 2018

Keywords

  • limb immobilization
  • countermeasures
  • amino acid
  • strength
  • ESSENTIAL AMINO-ACIDS
  • MYOFIBRILLAR PROTEIN-SYNTHESIS
  • HUMAN QUADRICEPS MUSCLE
  • BED-REST
  • OLDER-ADULTS
  • DISUSE ATROPHY
  • ELDERLY-MEN
  • IN-VIVO
  • NUTRITIONAL STRATEGIES
  • RESISTANCE EXERCISE

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