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.
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.


METHODS
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.


CONCLUSIONS
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.
Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia (RMD, SLO, NLM, CAG, DWD, and CAN), and the Baker IDI Heart and Diabetes Institute, Melbourne, Australia (DWD).
Robin M
RM
Daly
Stella L
SL
O'Connell
Niamh L
NL
Mundell
Carley A
CA
Grimes
David W
DW
Dunstan
Caryl A
CA
Nowson
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001823:Body Composition; D002762:Cholecalciferol / Q000627:therapeutic use; D015331:Cohort Studies; D003131:Combined Modality Therapy; D004044:Dietary Proteins / Q000009:adverse effects / Q000627:therapeutic use*; D019587:Dietary Supplements; D015536:Down-Regulation; D005260:Female; D005500:Follow-Up Studies; D016852:Housing for the Elderly; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008460:Meat / Q000009:adverse effects; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D055070:Resistance Training; D055948:Sarcopenia / Q000097:blood / Q000276:immunology / Q000473:pathology / Q000517:prevention & control*; D014739:Victoria
D004044:Dietary Proteins; C508600:IL6 protein, human; D015850:Interleukin-6; D002762:Cholecalciferol