The researchers exerimented with 100 women aged between 60 and 90. All of the women trained for four months, doing a weights workout twice a week. Each strength training session lasted one hour, including the warm-up and cool-down. In addition all of the women took 1000 IE vitamin D3 daily.
The researchers divided the women into two groups. One group ate a protein-rich meal that included about 80 g lean meat [RT+meat] twice a day, the other group ate more traditional meals containing large amounts of carbohydrates [CRT] twice a day.
The figure below gives an idea of the diets that the two groups followed. In terms of calories both diets were the same, but the women in the RT+meat group got more of their energy from protein and consumed more zinc than the women in the CRT group.
The women in the RT+meat group built up 500 g more lean body mass than the women in the other group in the four months that the experiment lasted.
What’s more, the women in the RT+meat group lost 500 g more body fat, and they gained noticeably more muscle strength than the women in the other group.
The researchers observed no effects of the meat-rich diet on the cholesterol levels or concentration of inflammatory proteins in the women’s blood. One exception was the concentration of the inflammatory protein interleukin-6. The concentration of interleukin-6 decreased in the RT+meat group.
The IGF-1 level also rose in the RT+meat group.
“From a public health perspective, these findings indicate that the elderly require a higher dietary protein intake to maximize the anabolic response to resistance training, and lean red meat can be safely used to modestly increase dietary protein in older people”, the researchers conclude.
The study was funded by, among others, Meat and Livestock Australia Ltd [mla.com.au], an organisation that represents the meat branch down under.
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.
Physical inactivity, inadequate dietary protein, and low-grade systemic inflammation contribute to age-related muscle loss, impaired function, and disability.
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.
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.
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. PMID: 24477043 [PubMed - in process] Source: http://www.ncbi.nlm.nih.gov/pubmed/24477043