Michael Tieland

Protein supplementation increases muscle mass gain during prolonged resistance-type exercise training in frail elderly people: a randomized, double-blind, placebo-controlled trial.

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.

Protein supplementation improves physical performance in frail elderly people: a randomized, double-blind, placebo-controlled trial.

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.

There Are No Nonresponders to Resistance-Type Exercise Training in Older Men and Women.

OBJECTIVE To assess the proposed prevalence of unresponsiveness of older men and women to augment lean body mass, muscle fiber size, muscle strength, and/or physical function following prolonged resistance-type exercise training. DESIGN/SETTING/PARTICIPANTS A retrospective analysis of the adaptive response to 12 (n = 110) and 24 (n = 85) weeks of supervised resistance-type exercise training in older (>65 years) men and women. MEASUREMENTS Lean body mass (DXA), type I and type II muscle fiber size (biopsy), leg strength (1-RM on leg press and leg extension), and physical function (chair-rise time) were assessed at baseline, and after 12 and 24 weeks of resistance-type exercise training. RESULTS Lean body mass increased by 0.9 ± 0.1 kg (range: -3.3 to +5.4 kg; P < .001) from 0 to 12 weeks of training. From 0 to 24 weeks, lean body mass increased by 1.1 ± 0.2 kg (range: -1.8 to +9.2 kg; P < .001). Type I and II muscle fiber size increased by 324 ± 137 μm(2) (range: -4458 to +3386 μm(2); P = .021), and 701 ± 137 μm(2) (range: -4041 to +3904 μm(2); P < .001) from 0 to 12 weeks. From 0 to 24 weeks, type I and II muscle fiber size increased by 360 ± 157 μm(2) (range: -3531 to +3426 μm(2); P = .026) and 779 ± 161 μm(2) (range: -2728 to +3815 μm(2); P < .001). The 1-RM strength on the leg press and leg extension increased by 33 ± 2 kg (range: -36 to +87 kg; P < .001) and 20 ± 1 kg (range: -22 to +56 kg; P < .001) from 0 to 12 weeks. From 0 to 24 weeks, leg press and leg extension 1-RM increased by 50 ± 3 kg (range: -28 to +145 kg; P < .001) and 29 ± 2 kg (range: -19 to +60 kg; P < .001). Chair-rise time decreased by 1.3 ± 0.4 seconds (range: +21.6 to -12.5 seconds; P = .003) from 0 to 12 weeks. From 0 to 24 weeks, chair-rise time decreased by 2.3 ± 0.4 seconds (range: +10.5 to -23.0 seconds; P < .001). Nonresponsiveness was not apparent in any subject, as a positive adaptive response on at least one training outcome was apparent in every subject. CONCLUSIONS A large heterogeneity was apparent in the adaptive response to prolonged resistance-type exercise training when changes in lean body mass, muscle fiber size, strength, and physical function were assessed in older men and women. The level of responsiveness was strongly affected by the duration of the exercise intervention, with more positive responses following more prolonged exercise training. We conclude that there are no nonresponders to the benefits of resistance-type exercise training on lean body mass, fiber size, strength, or function in the older population. Consequently, resistance-type exercise should be promoted without restriction to support healthy aging in the older population.

Coingestion of Carbohydrate and Protein Hydrolysate Stimulates Muscle Protein Synthesis during Exercise in Young Men, with No Further Increase during Subsequent Overnight Recovery

We investigated the effect of carbohydrate and protein hydrolysate ingestion on whole-body and muscle protein synthesis during a combined endurance and resistance exercise session and subsequent overnight recovery. Twenty healthy men were studied in the evening after consuming a standardized diet throughout the day. Subjects participated in a 2-h exercise session during which beverages containing both carbohydrate (0.15 g x kg(-1) x h(-1)) and a protein hydrolysate (0.15 g x kg(-1) x h(-1)) (C+P, n = 10) or water only (W, n = 10) were ingested. Participants consumed 2 additional beverages during early recovery and remained overnight at the hospital. Continuous i.v. infusions with L-[ring-(13)C(6)]-phenylalanine and L-[ring-(2)H(2)]-tyrosine were applied and blood and muscle samples were collected to assess whole-body and muscle protein synthesis rates. During exercise, whole-body and muscle protein synthesis rates increased by 29 and 48% with protein and carbohydrate coingestion (P < 0.05). Fractional synthetic rates during exercise were 0.083 +/- 0.011%/h in the C+P group and 0.056 +/- 0.003%/h in the W group, (P < 0.05). During subsequent overnight recovery, whole-body protein synthesis was 19% greater in the C+P group than in the W group (P < 0.05). However, mean muscle protein synthesis rates during 9 h of overnight recovery did not differ between groups and were 0.056 +/- 0.004%/h in the C+P group and 0.057 +/- 0.004%/h in the W group (P = 0.89). We conclude that, even in a fed state, protein and carbohydrate supplementation stimulates muscle protein synthesis during exercise. Ingestion of protein with carbohydrate during and immediately after exercise improves whole-body protein synthesis but does not further augment muscle protein synthesis rates during 9 h of subsequent overnight recovery.

Resistance Exercise Increases Postprandial Muscle Protein Synthesis in Humans

PURPOSE We examined the impact of an acute bout of resistance-type exercise on mixed muscle protein synthesis in the fed state. METHODS After a standardized breakfast, 10 untrained males completed a single, unilateral lower-limb resistance-type exercise session. A primed, continuous infusion of l-[ring-C6]phenylalanine was combined with muscle biopsy collection from both the exercised (Ex) and the nonexercised (NEx) leg to assess the impact of local muscle contractions on muscle protein synthesis rates after food intake. Western blotting with phosphospecific and pan antibodies was used to determine the phosphorylation status of AMP-activated kinase (AMPK), 4E-binding protein (4E-BP1), mammalian target of rapamycin (mTOR), and p70 ribosomal protein S6 kinase (S6K1). RESULTS Muscle protein synthesis rates were approximately 20% higher in Ex compared with NEx (0.098% +/- 0.005% vs 0.083% +/- 0.002%.h, respectively, P < 0.01). In the fed state, resistance-type exercise did not elevate AMPK phosphorylation. However, the phosphorylation status of 4E-BP1 was approximately 20% lower after cessation of exercise in Ex compared with NEx (P < 0.05). Conversely, 4E-BP1 phosphorylation was significantly higher in Ex compared with NEx after 6 h of recovery (P < 0.05) with no changes in mTOR phosphorylation. S6 phosphorylation was greater in Ex versus NEx after cessation of exercise (P < 0.05), although S6K1 phosphorylation at T was not up-regulated (P > 0.05). CONCLUSION We conclude that resistance-type exercise performed in a fed state further elevates postprandial muscle protein synthesis rates, which is accompanied by an increase in S6 and 4E-BP1 phosphorylation state.

Effect of resistance-type exercise training with or without protein supplementation on cognitive functioning in frail and pre-frail elderly: Secondary analysis of a randomized, double-blind, placebo-controlled trial

Physical activity has been proposed as one of the most effective strategies to prevent cognitive decline. Protein supplementation may exert an additive effect. The effect of resistance-type exercise training with or without protein supplementation on cognitive functioning in frail and pre-frail elderly people was assessed in a secondary analysis. Two 24-week, double-blind, randomized, placebo-controlled intervention studies were carried out in parallel. Subjects performed a resistance-type exercise program of two sessions per week (n=62) or no exercise program (n=65). In both studies, subjects were randomly allocated to either a protein (2×15 g daily) or a placebo drink. Cognitive functioning was assessed with a neuropsychological test battery focusing on the cognitive domains episodic memory, attention and working memory, information processing speed, and executive functioning. In frail and pre-frail elderly, resistance-type exercise training in combination with protein supplementation improved information processing speed (changes in domain score 0.08±0.51 versus -0.23±0.19 in the non-exercise group, p=0.04). Exercise training without protein supplementation was beneficial for attention and working memory (changes in domain scores 0.35±0.70 versus -0.12±0.69 in the non-exercise group, p=0.02). There were no significant differences among the intervention groups on the other cognitive tests or domain scores.

Handgrip strength does not represent an appropriate measure to evaluate changes in muscle strength during an exercise intervention program in frail older people.

INTRODUCTION Although handgrip strength is considered a strong predictor of negative health outcomes, it is unclear whether handgrip strength represents a useful measure to evaluate changes in muscle strength following resistance-type exercise training in older people. We assessed whether measuring handgrip strength provides proper insight in the efficacy of resistance-type exercise training to increase muscle mass, strength, and physical performance in frail older people. METHODS Prefrail and frail older people (≥ 65 y) were either conducting a 24-week resistance-type exercise training or no exercise training. Before, during, and after the intervention, handgrip strength (JAMAR), lean body mass (DXA), leg strength (1-RM), and physical performance (SPPB) were assessed. RESULTS Handgrip strength correlated with appendicular lean mass (r = 0.68; p < .001) and leg strength (r = 0.67; p < .001). After 24 weeks of whole body resistance-type exercise training, leg extension strength improved significantly better when compared with the control group (57 ± 2-78 ± 3 kg vs 57 ± 3-65 ± 3 kg: p < .001). Moreover, physical performance improved significantly more in the exercise group (8.0 ± 0.4-9.3 ± 0.4 points) when compared with the control group (8.3 ± 0.4-8.9 ± 0.4 points: p < .05). These positive changes were not accompanied with any significant changes in handgrip strength (26.3 ± 1.2-27.6 ± 1.2 kg in the exercise group vs 26.6 ± 1.2-26.3 ± 1.3 kg in the control group: p = .71). CONCLUSION Although handgrip strength strongly correlates with muscle mass and leg strength in frail older people, handgrip strength does not provide a valid means to evaluate the efficacy of exercise intervention programs to increase muscle mass or strength in an older population.

Dietary Protein Intake in Dutch Elderly People: A Focus on Protein Sources

Introduction: Sufficient high quality dietary protein intake is required to prevent or treat sarcopenia in elderly people. Therefore, the intake of specific protein sources as well as their timing of intake are important to improve dietary protein intake in elderly people. Objectives: to assess the consumption of protein sources as well as the distribution of protein sources over the day in community-dwelling, frail and institutionalized elderly people. Methods: Habitual dietary intake was evaluated using 2- and 3-day food records collected from various studies involving 739 community-dwelling, 321 frail and 219 institutionalized elderly people. Results: Daily protein intake averaged 71 ± 18 g/day in community-dwelling, 71 ± 20 g/day in frail and 58 ± 16 g/day in institutionalized elderly people and accounted for 16% ± 3%, 16% ± 3% and 17% ± 3% of their energy intake, respectively. Dietary protein intake ranged from 10 to 12 g at breakfast, 15 to 23 g at lunch and 24 to 31 g at dinner contributing together over 80% of daily protein intake. The majority of dietary protein consumed originated from animal sources (≥60%) with meat and dairy as dominant sources. Thus, 40% of the protein intake in community-dwelling, 37% in frail and 29% in institutionalized elderly originated from plant based protein sources with bread as the principle source. Plant based proteins contributed for >50% of protein intake at breakfast and between 34% and 37% at lunch, with bread as the main source. During dinner, >70% of the protein intake originated from animal protein, with meat as the dominant source. Conclusion: Daily protein intake in these older populations is mainly (>80%) provided by the three main meals, with most protein consumed during dinner. More than 60% of daily protein intake consumed is of animal origin, with plant based protein sources representing nearly 40% of total protein consumed. During dinner, >70% of the protein intake originated from animal protein, while during breakfast and lunch a large proportion of protein is derived from plant based protein sources.

The Muscle Metabolome Differs between Healthy and Frail Older Adults

Populations around the world are aging rapidly. Age-related loss of physiological functions negatively affects quality of life. A major contributor to the frailty syndrome of aging is loss of skeletal muscle. In this study we assessed the skeletal muscle biopsy metabolome of healthy young, healthy older and frail older subjects to determine the effect of age and frailty on the metabolic signature of skeletal muscle tissue. In addition, the effects of prolonged whole-body resistance-type exercise training on the muscle metabolome of older subjects were examined. The baseline metabolome was measured in muscle biopsies collected from 30 young, 66 healthy older subjects, and 43 frail older subjects. Follow-up samples from frail older (24 samples) and healthy older subjects (38 samples) were collected after 6 months of prolonged resistance-type exercise training. Young subjects were included as a reference group. Primary differences in skeletal muscle metabolite levels between young and healthy older subjects were related to mitochondrial function, muscle fiber type, and tissue turnover. Similar differences were observed when comparing frail older subjects with healthy older subjects at baseline. Prolonged resistance-type exercise training resulted in an adaptive response of amino acid metabolism, especially reflected in branched chain amino acids and genes related to tissue remodeling. The effect of exercise training on branched-chain amino acid-derived acylcarnitines in older subjects points to a downward shift in branched-chain amino acid catabolism upon training. We observed only modest correlations between muscle and plasma metabolite levels, which pleads against the use of plasma metabolites as a direct read-out of muscle metabolism and stresses the need for direct assessment of metabolites in muscle tissue biopsies.

Protein intake and lean body mass preservation during energy intake restriction in overweight older adults

Background:Dietary-induced weight loss is generally accompanied by a decline in skeletal muscle mass. The loss of muscle mass leads to a decline in muscle strength and impairs physical performance. A high dietary protein intake has been suggested to allow muscle mass preservation during energy intake restriction.Objective:To investigate the impact of increasing dietary protein intake on lean body mass, strength and physical performance during 12 weeks of energy intake restriction in overweight older adults.Design:Sixty-one overweight and obese men and women (63±5 years) were randomly assigned to either a high protein diet (HP; 1.7 g kg−1 per day; n=31) or normal protein diet (NP; 0.9 g kg−1 per day; n=30) during a 12-week 25% energy intake restriction. During this controlled dietary intervention, 90% of the diet was provided by the university. At baseline and after the intervention, body weight, lean body mass (dual-energy X-ray absorptiometry), leg strength (1-repetition maximum), physical performance (Short Physical Performance Battery, 400 m) and habitual physical activity (actigraph) were assessed.Results:Body weight declined in both groups with no differences between the HP and NP groups (−8.9±2.9 versus −9.1±3.4 kg, respectively; P=0.584). Lean body mass declined by 1.8±2.2 and 2.1±1.4 kg, respectively, with no significant differences between groups (P=0.213). Leg strength had decreased during the intervention by 8.8±14.0 and 8.9±12.8 kg, with no differences between groups (P=0.689). Physical performance as measured by 400 m walking speed improved in both groups, with no differences between groups (P=0.219).Conclusions:Increasing protein intake above habitual intake levels (0.9 g kg−1 per day) does not preserve lean body mass, strength or physical performance during prolonged energy intake restriction in overweight older adults.