Protein-enriched Diet, With the Use of Lean Red Meat, Combined With Progressive Resistance Training Enhances Lean Tissue Mass and Muscle Strength and Reduces Circulating IL-6 Concentrations in Elderly Women: A Cluster Randomized Controlled Trial

Am J Clin Nutr. 2014 Apr;99(4):899-910. doi: 10.3945/ajcn.113.064154. Epub 2014 Jan 29.

Abstract

Background: Physical inactivity, inadequate dietary protein, and low-grade systemic inflammation contribute to age-related muscle loss, impaired function, and disability.

Objective: We assessed the effects of progressive resistance training (PRT) combined with a protein-enriched diet facilitated through lean red meat on lean tissue mass (LTM), muscle size, strength and function, circulating inflammatory markers, blood pressure, and lipids in elderly women.

Design: In a 4-mo cluster randomized controlled trial, 100 women aged 60-90 y who were residing in 15 retirement villages were allocated to receive PRT with lean red meat (∼160 g cooked) to be consumed 6 d/wk [resistance training plus lean red meat (RT+Meat) group; n = 53] or control PRT [1 serving pasta or rice/d; control resistance training (CRT) group; n = 47)]. All women undertook PRT 2 times/wk and received 1000 IU vitamin D3/d.

Results: The mean (± SD) protein intake was greater in the RT+Meat group than in the CRT group throughout the study (1.3 ± 0.3 compared with 1.1 ± 0.3 g · kg⁻¹ · d⁻¹, respectively; P < 0.05). The RT+Meat group experienced greater gains in total body LTM (0.45 kg; 95% CI: 0.07, 0.84 kg), leg LTM (0.22 kg; 95% CI: 0.02, 0.42 kg), and muscle strength (18%; 95% CI: 0.03, 0.34) than did the CRT group (all P < 0.05). The RT+Meat group also experienced a 10% greater increase in serum insulin-like growth factor I (P < 0.05) and a 16% greater reduction in the proinflammatory marker interleukin-6 (IL-6) (P < 0.05) after 4 mo. There were no between-group differences for the change in blood lipids or blood pressure.

Conclusion: A protein-enriched diet equivalent to ∼1.3 g · kg⁻¹ · d⁻¹ achieved through lean red meat is safe and effective for enhancing the effects of PRT on LTM and muscle strength and reducing circulating IL-6 concentrations in elderly women. This trial was registered at the Australian Clinical Trials Registry as ACTRN12609000223235.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Animals
  • Body Composition
  • Cholecalciferol / therapeutic use
  • Cohort Studies
  • Combined Modality Therapy
  • Dietary Proteins / adverse effects
  • Dietary Proteins / therapeutic use*
  • Dietary Supplements
  • Down-Regulation*
  • Female
  • Follow-Up Studies
  • Housing for the Elderly
  • Humans
  • Interleukin-6 / blood*
  • Meat* / adverse effects
  • Middle Aged
  • Muscle Strength
  • Muscle, Skeletal / immunology
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / pathology
  • Resistance Training*
  • Sarcopenia / blood
  • Sarcopenia / immunology
  • Sarcopenia / pathology
  • Sarcopenia / prevention & control*
  • Victoria

Substances

  • Dietary Proteins
  • IL6 protein, human
  • Interleukin-6
  • Cholecalciferol