title: Protein supplementation during resistance-type exercise training in the elderly.
abstract: BACKGROUND
  Resistance training has been well established as an effective treatment strategy to increase skeletal muscle mass and strength in the elderly. We assessed whether dietary protein supplementation can further augment the adaptive response to prolonged resistance-type exercise training in healthy elderly men and women.
  
  
  METHODS
  Healthy elderly men (n = 31, 70 ± 1 yr) and women (n = 29, 70 ± 1 yr) were randomly assigned to a progressive, 24-wk resistance-type exercise training program with or without additional protein supplementation (15 g·d-1). Muscle hypertrophy was assessed on a whole-body Dual-energy X-ray absorptiometry (DXA), limb (computed tomography), and muscle fiber (biopsy) level. Strength was assessed regularly by 1-repetition maximum (RM) strength testing. Functional capacity was assessed with a sit-to-stand and handgrip test.
  
  
  RESULTS
  One-RM strength increased by 45% ± 6% versus 40% ± 3% (women) and 41% ± 4% versus 44% ± 3% (men) in the placebo versus protein group, respectively (P < 0.001), with no differences between groups. Leg muscle mass (women, 4% ± 1% vs 3% ± 1%; men, 3% ± 1% vs 3% ± 1%) and quadriceps cross-sectional area (women, 9% ± 1% vs 9% ± 1%; men, 9% ± 1% vs 10% ± 1%) increased similarly in the placebo versus protein groups (P < 0.001). Type II muscle fiber size increased over time in both placebo and protein groups (25% ± 13% vs 30% ± 9% and 23% ± 12% vs 22% ± 10% in the women and men, respectively). Sit-to-stand improved by 18% ± 2% and 19% ± 2% in women and men, respectively (P < 0.001).
  
  
  CONCLUSIONS
  Prolonged resistance-type exercise training increases skeletal muscle mass and strength, augments functional capacity, improves glycemia and lipidemia, and reduces blood pressure in healthy elderly men and women. Additional protein supplementation (15 g·d-1) does not further increase muscle mass, strength, and/or functional capacity.
authors.affiliation: Top Institute Food and Nutrition, Wageningen, The Netherlands.
authors.forename: Marika
authors.initials: M
authors.lastname: Leenders
authors.forename: Lex B
authors.initials: LB
authors.lastname: Verdijk
authors.forename: Letty
authors.initials: L
authors.lastname: Van der Hoeven
authors.forename: Janneau
authors.initials: J
authors.lastname: Van Kranenburg
authors.forename: Rachel
authors.initials: R
authors.lastname: Nilwik
authors.forename: Will K W H
authors.initials: WK
authors.lastname: Wodzig
authors.forename: Joan M G
authors.initials: JM
authors.lastname: Senden
authors.forename: Hans A
authors.initials: HA
authors.lastname: Keizer
authors.forename: Luc J C
authors.initials: LJ
authors.lastname: Van Loon
mesh_terms: D015502:Absorptiometry, Photon; D000222:Adaptation, Physiological; D000368:Aged; D000704:Analysis of Variance; D001823:Body Composition; D002784:Cholesterol / Q000097:blood; D003404:Creatinine / Q000097:blood; D004044:Dietary Proteins / Q000008:administration & dosage*; D019587:Dietary Supplements; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D018737:Hand Strength; D006801:Humans; D007333:Insulin Resistance; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D018656:Muscle Fibers, Fast-Twitch / Q000166:cytology; D053580:Muscle Strength; D009584:Nitrogen / Q000652:urine; D052097:Quadriceps Muscle / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D055070:Resistance Training; D014057:Tomography, X-Ray Computed
chemical_list: D002784:Cholesterol; D003404:Creatinine; D004044:Dietary Proteins; D006442:Glycated Hemoglobin; D008077:Lipoproteins, LDL; D009584:Nitrogen