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<sup>-1</sup> ⋅ d<sup>-1</sup>, 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<sup>-1</sup> ⋅ d<sup>-1</sup> 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.
<b>BACKGROUND: </b>Whey protein supplementation may augment resistance exercise-induced increases in muscle strength and mass. Further studies are required to determine whether this effect extends to mobility-limited older adults. The objectives of the study were to compare the effects of whey protein concentrate (WPC) supplementation to an isocaloric control on changes in whole-body lean mass, mid-thigh muscle cross-sectional area, muscle strength, and stair-climbing performance in older mobility-limited adults in response to 6 months of resistance training (RT).<b>METHODS: </b>Eighty mobility-limited adults aged 70-85 years were randomized to receive WPC (40g/day) or an isocaloric control for 6 months. All participants also completed a progressive high-intensity RT intervention. Sample sizes were calculated based on the primary outcome of change in whole-body lean mass to give 80% power for a 0.05-level, two-sided test.<b>RESULTS: </b>Lean mass increased 1.3% and 0.6% in the WPC and control groups, respectively. Muscle cross-sectional area was increased 4.6% and 2.9% in the WPC and control groups, respectively, and muscle strength increased 16%-50% in WPC and control groups. Stair-climbing performance also improved in both groups. However, there were no statistically significant differences in the change in any of these variables between groups.<b>CONCLUSIONS: </b>These data suggest that WPC supplementation at this dose does not offer additional benefit to the effects of RT in mobility-limited older adults.
Abstract: OBJECTIVES: Protein supplementation has been proposed as an effective dietary strategy to augment the skeletal muscle adaptive response to prolonged resistance-type exercise training in elderly people. Our objective was to assess the impact of protein supplementation on muscle mass, strength, and physical performance during prolonged resistance-type exercise training in frail elderly men and women. Design/setting/participants: A randomized, double-blind, placebo-controlled trial with 2 arms in parallel among 62 frail elderly subjects (78 ± 1 year). These elderly subjects participated in a progressive resistance-type exercise training program (2 sessions per week for 24 weeks) during which they were supplemented twice daily with either protein (2 ∗ 15 g) or a placebo. Measurements: Lean body mass (DXA), strength (1-RM), and physical performance (SPPB) were assessed at baseline, and after 12 and 24 weeks of intervention. RESULTS: Lean body mass increased from 47.2 kg (95% CI, 43.5–50.9) to 48.5 kg (95% CI, 44.8–52.1) in the protein group and did not change in the placebo group (from 45.7 kg, 95% CI, 42.1–49.2 to 45.4 kg, 95% CI, 41.8–48.9) following the intervention (P value for treatment × time interaction = .006). Strength and physical performance improved significantly in both groups (P = .000) with no interaction effect of dietary protein supplementation. CONCLUSIONS: Prolonged resistance-type exercise training represents an effective strategy to improve strength and physical performance in frail elderly people. Dietary protein supplementation is required to allow muscle mass gain during exercise training in frail elderly people. Trial Registration: clinicaltrials.gov identifier: NCT01110369.
Abstract: OBJECTIVES: Protein supplementation has been proposed as an effective dietary strategy to increase skeletal muscle mass and improve physical performance in frail elderly people. Our objective was to assess the impact of 24 weeks of dietary protein supplementation on muscle mass, strength, and physical performance in frail elderly people. Design/setting/participants: A total of 65 frail elderly subjects were included and randomly allocated to either daily protein or placebo supplementation (15 g protein at breakfast and lunch). Measurements: Skeletal muscle mass (DXA), muscle fiber size (muscle biopsy), strength (1-RM), and physical performance (SPPB) were assessed at baseline, and after 12 and 24 weeks of dietary intervention. RESULTS: Skeletal muscle mass did not change in the protein- (from 45.8 ± 1.7 to 45.8 ± 1.7 kg) or placebo-supplemented group (from 46.7 ± 1.7 to 46.6 ± 1.7 kg) following 24 weeks of intervention (P > .05). In accordance, type I and II muscle fiber size did not change over time (P > .05). Muscle strength increased significantly in both groups (P < .01), with leg extension strength tending to increase to a greater extent in the protein (57 ± 5 to 68 ± 5 kg) compared with the placebo group (57 ± 5 to 63 ± 5 kg) (treatment × time interaction effect: P = .059). Physical performance improved significantly from 8.9 ± 0.6 to 10.0 ± 0.6 points in the protein group and did not change in the placebo group (from 7.8 ± 0.6 to 7.9 ± 0.6 points) (treatment × time interaction effect: P = .02). CONCLUSION: Dietary protein supplementation improves physical performance, but does not increase skeletal muscle mass in frail elderly people.
BACKGROUND: Sarcopenia is strongly associated with an inadequate intake of dietary protein. Dietary protein supplementation boosts muscle-protein synthesis and increases muscle mass in the elderly. This study tested whether adding a protein-rich food, ricotta cheese, to the habitual diet increased total appendicular skeletal muscle mass and strength in elderly people.
METHODS: Participants (n = 40), were sarcopenic elderly men and women over 60 years of age. Two comparison groups were formed at random and followed for 3 months: the intervention group received 210 g/day of ricotta cheese plus the habitual diet, while the control group followed the habitual diet with no additional intervention. Total appendicular skeletal muscle (TASM) was assessed by dual-energy X-ray absorptiometry, while strength was measured using a handheld dynamometer at baseline and after the intervention period. The primary outcomes were the percentage of relative change in TASM and strength.
RESULTS: The percentage of relative change in TASM was not significant between the groups after the intervention period. Muscle strength improved in the intervention group, but showed only a tendency towards significance (P = 0.06). Secondary analysis showed that the men in the intervention group gained 270 g in TASM compared to those in the control group, and improved their fasting insulin levels (P = 0.05), muscle strength, lean body mass in the arms, and body weight variables.
CONCLUSION: The results of this study indicate that a nutritional intervention using a high-quality protein food, specifically ricotta cheese, in order to increase the amount of protein intake might not be regarded as fully promising in elderly men and women with sarcopenia. However, the gender effects on muscle strength, lean tissue in the arms, homeostatic assessment of insulin resistance, and body weight detected in this study suggest that additional research is needed on elderly male subjects with sarcopenia.
The loss of muscle mass with aging has been, at least partly, attributed to a blunted muscle protein synthetic response to food intake. Leucine coingestion has been reported to stimulate postprandial insulin release and augment postprandial muscle protein accretion. We assessed the clinical benefits of 6 mo of leucine supplementation in elderly, type 2 diabetes patients. Sixty elderly males with type 2 diabetes (age, 71 ± 1 y; BMI, 27.3 ± 0.4 kg/m(2)) were administered 2.5 g L-leucine (n = 30) or a placebo (n = 30) with each main meal during 6 mo of nutritional intervention (7.5 g/d leucine or placebo). Body composition, muscle fiber characteristics, muscle strength, glucose homeostasis, and basal plasma amino acid and lipid concentrations were assessed prior to, during, and after intervention. Lean tissue mass did not change or differ between groups and at 0, 3, and 6 mo were 61.9 ± 1.1, 62.2 ± 1.1, and 62.0 ± 1.0 kg, respectively, in the leucine group and 62.2 ± 1.3, 62.2 ± 1.3, and 62.2 ± 1.3 kg in the placebo group. There also were no changes in body fat percentage, muscle strength, and muscle fiber type characteristics. Blood glycosylated hemoglobin did not change or differ between groups and was 7.1 ± 0.1% in the leucine group and 7.2 ± 0.2% in the placebo group. Consistent with this, oral glucose insulin sensitivity and plasma lipid concentrations did not change or differ between groups. We conclude that prolonged leucine supplementation (7.5 g/d) does not modulate body composition, muscle mass, strength, glycemic control, and/or lipidemia in elderly, type 2 diabetes patients who habitually consume adequate dietary protein.
BACKGROUND & AIMS: Previous studies reported a severely impaired energy balance in COPD patients during the first days of an acute exacerbation, mainly due to a decreased energy and protein intake. The aim of the study was to investigate the feasibility and effectiveness of energy- and protein-rich nutritional supplements during hospitalization for an acute exacerbation in nutritionally depleted COPD patients.
METHODS: In a randomized double-blind, placebo-controlled two-center trial, 56 COPD patients were randomized and 47 patients completed the study. Nutritional intervention consisted of 3 x 125 ml (2.38 MJ/day) and the placebo group received similar amounts of a non-caloric fluid. Medical therapy and dietetic consultation were standardized and dietary intake was measured daily. Body composition, respiratory and skeletal muscle strength, lung function and symptoms were measured on admission and on days 4 and 8 of hospitalization.
RESULTS: Forty-seven percent of the patients had experienced recent involuntary weight loss prior to admission. The degree of weight loss was inversely related to resting arterial oxygen tension (r = 0.31; P < 0.05). Nutritional intervention resulted in a significant increase in energy (16% vs. placebo) and protein intake (38% vs. placebo). Mean duration of hospitalization was 9 +/- 2 days. Relative to usual care, no additional improvements in lung function or muscle strength were seen after nutritional intervention.
CONCLUSIONS: Oral nutritional supplementation during hospitalization for an acute exacerbation is feasible in nutritionally depleted COPD patients and does not interfere with normal dietary intake.
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.
