title: 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.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Carnegie Faculty, School of Sport, Leeds Beckett University, Leeds, UK.
authors.forename: T
authors.initials: T
authors.lastname: Ispoglou
authors.affiliation: Carnegie Faculty, School of Sport, Leeds Beckett University, Leeds, UK.
authors.forename: H
authors.initials: H
authors.lastname: White
authors.affiliation: Scottish Universities Environmental Research Centre, University of Glasgow, Glasgow, Scotland.
authors.forename: T
authors.initials: T
authors.lastname: Preston
authors.forename: S
authors.initials: S
authors.lastname: McElhone
authors.affiliation: Carnegie Faculty, School of Sport, Leeds Beckett University, Leeds, UK.
authors.forename: J
authors.initials: J
authors.lastname: McKenna
authors.affiliation: Carnegie Faculty, School of Sport, Leeds Beckett University, Leeds, UK.
authors.forename: K
authors.initials: K
authors.lastname: Hind
mesh_terms: D000368:Aged; D001823:Body Composition / Q000187:drug effects*; D004044:Dietary Proteins / Q000008:administration & dosage*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005080:Exercise Test / Q000379:methods; D005260:Female; D018737:Hand Strength; D064368:Healthy Volunteers; D006801:Humans; D007930:Leucine / Q000008:administration & dosage*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D053580:Muscle Strength / Q000187:drug effects; D018482:Muscle, Skeletal / Q000502:physiology; D010865:Pilot Projects; D016138:Walking
chemical_list: D004044:Dietary Proteins; D007930:Leucine