scholarly journals The role of dietary protein in optimizing muscle mass, function and health outcomes in older individuals

2012 ◽  
Vol 108 (S2) ◽  
pp. S88-S93 ◽  
Author(s):  
Robert R. Wolfe
Keyword(s):  
Protein Synthesis ◽  
Health Outcomes ◽  
Muscle Mass ◽  
Dietary Protein ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Dietary Protein Intake ◽  
Older Individuals ◽  
And Function

The determination of whether increased dietary protein can positively affect health outcomes is hindered by the absence of prospective, randomized trials directly addressing this issue in which all pertinent variables are controlled. Consequently, we can only address the question deductively by considering the support for the rationale underlying the notion of a beneficial effect of increased dietary protein intake. With regard to health outcomes, we have focused on older individuals. Muscle mass and function are progressively lost with aging, so that by the age of 60 many individuals have reached a threshold where function begins to be affected. An association between reduced muscle mass and strength and unfavourable health outcomes is more likely to be revealed in individuals who have significant decrements in muscle mass and strength. In this article support for the rationale underlying the notion of a beneficial effect of increased dietary protein intake is considered. Dietary protein intake, and the resulting increased availability of plasma amino acids, stimulates muscle protein synthesis. If all other variables are controlled, increased muscle protein synthesis leads to improved muscle mass, strength and function over time. Increased muscle mass, strength and function are related to improved health outcomes in older individuals. Since adverse effects of reasonable increases in protein intake above the recommended dietary allowance (RDA) of 0·8 g protein/kg/day have not been reported, it is reasonable to conclude that the optimal protein intake for an older individual is greater than the RDA.

DIETARY PROTEIN TO MAINTAIN MUSCLE MASS IN AGING: A CASE FOR PER-MEAL PROTEIN RECOMMENDATIONS

2016 ◽  
pp. 1-10
Author(s):  
C.H. MURPHY ◽  
S.Y. OIKAWA ◽  
S.M. PHILLIPS
Keyword(s):  
Muscle Mass ◽  
Dietary Protein ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Dietary Advice ◽  
Age Related ◽  
Meal Protein ◽  
Single Meal ◽  
And Function

It is well accepted that daily protein intake is an important dietary consideration to limit and treat age-related declines in muscle mass, strength, and function. Furthermore, we propose that there is a growing appreciation for the need to consider protein intake on a per-meal basis rather than simply focusing on the total daily protein intake. The existence of a saturable dose-response relationship between muscle protein synthesis (MPS) and the quantity of protein consumed in a single meal/bolus provides the rationale for promoting an even/balanced pattern of daily protein intake. We hypothesize that a balanced/even protein intake pattern with the ingestion a quantity of protein shown to optimally stimulate MPS at each meal may be an effective strategy to alleviate sarcopenic muscle loss. In this review we examine the available evidence supporting the influence of dietary protein intake pattern on muscle protein turnover, muscle mass, and muscle function. We present several practical considerations that, it is proposed, should be taken into account when translating a per-meal protein recommendation into dietary advice for older adults.

scholarly journals Dietary protein intake impacts human skeletal muscle protein fractional synthetic rates after endurance exercise

2005 ◽  
Vol 289 (4) ◽  
pp. E678-E683 ◽  
Author(s):  
Douglas R. Bolster ◽  
Matthew A. Pikosky ◽  
P. Courtney Gaine ◽  
William Martin ◽  
Robert R. Wolfe ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Endurance Exercise ◽  
Dietary Protein ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Dietary Protein Intake ◽  
Skeletal Muscle Protein ◽  
Skeletal Muscle Protein Synthesis

This investigation evaluated the physiological impact of different dietary protein intakes on skeletal muscle protein synthesis postexercise in endurance runners. Five endurance-trained, male runners participated in a randomized, crossover design diet intervention, where they consumed either a low (0.8 g/kg; LP)-, moderate (1.8 g/kg; MP)-, or high (3.6 g/kg; HP)-protein diet for 4 wk. Diets were designed to be eucaloric with carbohydrate, fat, and protein approximating 60, 30, and 10%; 55, 30, and 15%; and 40, 30, and 30% for LP, MP, and HP, respectively. Substrate oxidation was assessed via indirect calorimetry at 3 wk of the dietary interventions. Mixed-muscle protein fractional synthetic rate (FSR) was measured after an endurance run (75 min at 70% V̇o2 peak) using a primed, continuous infusion of [2H5]phenylalanine. Protein oxidation increased with increasing protein intake, with each trial being significantly different from the other ( P < 0.01). FSR after exercise was significantly greater for LP (0.083%/h) and MP (0.078%/h) than for HP (0.052%/h; P < 0.05). There was no difference in FSR between LP and MP. This is the first investigation to establish that habitual dietary protein intake in humans modulates skeletal muscle protein synthesis after an endurance exercise bout. Future studies directed at mechanisms by which level of protein intake influences skeletal muscle turnover are needed.

scholarly journals Higher Protein Intake Does Not Augment Muscle Protein Synthetic Responses During the Early Stages of Resistance Training in Middle-Aged Adults

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 520-520
Author(s):  
Amadeo Salvador ◽  
Colleen McKenna ◽  
Kevin J.M. Paulussen ◽  
Alexander Keeble ◽  
Andrew Askow ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Training ◽  
Dietary Protein ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Protein Fractions ◽  
Dietary Protein Intake ◽  
Middle Aged ◽  
Middle Aged Adults

Abstract Objectives Dietary protein intake augments muscle protein synthesis rates during acute recovery from resistance exercise training (RET) and can help offset age-related loss in muscle mass. Skeletal muscle tissue contains a variety of different protein pools such as myofibrillar (contractile), mitochondrial (substrate oxidation), and collagen (structural support) proteins that have been reported to have different contraction and nutrient sensitivities in controlled laboratory studies. However, no study has investigated the impact of dietary protein intake on the synthesis of these specific muscle proteins fractions during RET in a free-living setting. Therefore, we investigated the effect of dietary protein intake on daily muscle protein synthesis rates (PS) within the myofibrillar (MyoPS), mitochondrial (MitoPS), and collagen (CPS) protein fractions throughout the early phase (0 – 3 wks) of RET in middle-aged adults. Methods Twenty middle-aged adults (47 ± 1 y, BMI 28 ± 1 kg/m2, M = 12, F = 8) were stratified and randomized to consume either moderate (MOD; 1.06 ± 0.22 g/kg/d) or high (HI; 1.55 ± 0.25 g/kg/d) amounts of protein during a dietary counseling-controlled resistance training program. On day 0, participants ingested intermittent boluses of deuterated (2H) water followed by daily maintenance doses throughout the study period. Muscle biopsies were collected prior to and at weeks 1, 2, and 3 of the intervention to assess MyoPS, MitoPS, and CPS by LC/MS. Results MitoPS decreased at 0–3 wks when compared to 0–1 wks (P = 0.010, CI: −0.77 – −0.10%/d) regardless of group (HI: 0.64 ± 0.32%/d and MOD 0.86 ± 0.55%/d; P = 0.827). A similar decline was also observed for CPS (group P = 0.323; time P = 0.007). The MyoPS in the HI condition remained constant (0–1 wk: 0.81 ± 0.42%/d and 0–3 wks: 0.81 ± 0.72%/d, P = 1.0), but MOD decreased over time (0–1 wk: 1.35 ± 0.9%/d and 0–3 wks: 0.77 ± 0.43%/d, P = 0.023). Conclusions Our results demonstrated that additional protein intake above moderate amounts does not meaningfully potentiate the stimulation of longer-term muscle protein synthetic responses within the myofibrillar, mitochondrial, or collagen protein fractions during the early stages of a RET in middle-aged adults. Funding Sources Funded in part by the Beef Checkoff. AFS funded by CAPES Scholarship.

Dietary protein considerations for muscle protein synthesis and muscle mass preservation in older adults

2020 ◽  
pp. 1-11 ◽  
Author(s):  
Eunice T. Olaniyan ◽  
Fiona O’Halloran ◽  
Aoife L. McCarthy
Keyword(s):  
Older Adults ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Mass ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Adult Population ◽  
Anabolic Resistance

Abstract Amino acid bioavailability is critical for muscle protein synthesis (MPS) and preservation of skeletal muscle mass (SMM). Ageing is associated with reduced responsiveness of MPS to essential amino acids (EAA). Further, the older adult population experiences anabolic resistance, leading to increased frailty, functional decline and depleted muscle mass preservation, which facilitates the need for increased protein intake to increase their SMM. This review focuses on the role of proteins in muscle mass preservation and examines the contribution of EAA and protein intake patterns to MPS. Leucine is the most widely studied amino acid for its role as a potent stimulator of MPS, though due to inadequate data little is yet known about the role of other EAA. Reaching a conclusion on the best pattern of protein intake has proven difficult due to conflicting studies. A mixture of animal and plant proteins can contribute to increased MPS and potentially attenuate muscle wasting conditions; however, there is limited research on the biological impact of protein blends in older adults. While there is some evidence to suggest that liquid protein foods with higher than the RDA of protein may be the best strategy for achieving high MPS rates in older adults, clinical trials are warranted to confirm an association between food form and SMM preservation. Further research is warranted before adequate recommendations and strategies for optimising SMM in the elderly population can be proposed.

scholarly journals Daily Protein and Energy Intake Are Not Associated with Muscle Mass and Physical Function in Healthy Older Individuals—A Cross-Sectional Study

Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2794
Author(s):  
Grith Højfeldt ◽  
Yusuke Nishimura ◽  
Kenneth Mertz ◽  
Simon R. Schacht ◽  
Jonas Lindberg ◽  
...  
Keyword(s):  
Physical Function ◽  
Muscle Mass ◽  
Energy Intake ◽  
Dietary Protein ◽  
Protein Intake ◽  
Cross Sectional Study ◽  
Dietary Protein Intake ◽  
Older Individuals ◽  
Sectional Study ◽  
Cross Sectional

Dietary protein has a pivotal role in muscle mass maintenance with advancing age. However, an optimal dose and distribution of protein intake across the day as well as the interaction with energy intake for the maintenance of muscle mass and physical function in healthy older adults remain to be fully elucidated. The purpose of this study was to examine the association between muscle mass, strength, and physical function, and the total amount and distribution of protein and energy intake across the day in healthy older individuals. The research question was addressed in a cross-sectional study including 184 Danish men and woman (age: 70.2 ± 3.9 years, body mass: 74.9 ± 12.1 kg, Body Mass Index (BMI): 25.4 ± 3.7 kg/m2) where a 3-day dietary registration, muscle mass, strength, and functional measurements were collected. We found that neither daily total protein intake nor distribution throughout the day were associated with muscle mass, strength, or physical function. Consequently, we do not provide an incentive for healthy older Danish individuals who already adhere to the current internationally accepted recommended dietary protein intake (0.83 g/kg/day) to change dietary protein intake or its distribution pattern throughout the day.

scholarly journals Effect of fast dietary proteins on muscle protein synthesis rate and muscle strength in ad libitum-fed and energy-restricted old rats

2011 ◽  
Vol 106 (11) ◽  
pp. 1683-1690 ◽  
Author(s):  
Stéphane Walrand ◽  
Aude Zangarelli ◽  
Christelle Guillet ◽  
Jérôme Salles ◽  
Karine Soulier ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Muscle Strength ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Old Rats ◽  
And Function ◽  
Muscle Protein Synthesis Rate

Sarcopenia is defined as age-related loss of muscle mass and strength. Energy restriction (ER) delays fibre loss by limiting the accumulated deleterious effects of reactive oxygen species on muscle. However, insufficient protein intake during ER might affect muscle mass and function. We hypothesised that ingestion of fast-digested proteins such as whey protein (WP) improves muscle protein synthesis and muscle strength in aged ER rats. The effect of WP or casein (CAS, slow protein) on muscle mass, protein synthesis and strength was evaluated in 21-month-old rats fed for 5 months either ad libitum (AL) or a 40 % protein and energy-restricted (PER) or 40 % AL-isonitrogenous ER diet. The nitrogen balance was reduced in PER-CAS rats only ( − 48 % v. AL-CAS). WP stimulated muscle protein synthesis rates compared with CAS in all groups (+21,+37 and +34 % in AL, PER and ER conditions, respectively). Muscle strength was higher in ER rats than in AL rats (+23 and +12 % for WP or CAS, respectively). Muscle performance tended to be greater in ER rats fed WP than in ER-CAS rats (P < 0·09). In conclusion, we observed that long-term ER combined with maintained protein intake had a beneficial impact on muscle protein synthesis rate and function during ageing.

scholarly journals Targeting the Gut Microbiota to Improve Dietary Protein Efficacy to Mitigate Sarcopenia

2021 ◽  
Vol 8 ◽  
Author(s):  
Elena de Marco Castro ◽  
Caoileann H. Murphy ◽  
Helen M. Roche
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Gut Microbiota ◽  
Muscle Mass ◽  
Dietary Protein ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Low Grade ◽  
Ageing Population ◽  
Anabolic Resistance

Sarcopenia is characterised by the presence of diminished skeletal muscle mass and strength. It is relatively common in older adults as ageing is associated with anabolic resistance (a blunted muscle protein synthesis response to dietary protein consumption and resistance exercise). Therefore, interventions to counteract anabolic resistance may benefit sarcopenia prevention and are of utmost importance in the present ageing population. There is growing speculation that the gut microbiota may contribute to sarcopenia, as ageing is also associated with [1) dysbiosis, whereby the gut microbiota becomes less diverse, lacking in healthy butyrate-producing microorganisms and higher in pathogenic bacteria, and [2) loss of epithelial tight junction integrity in the lining of the gut, leading to increased gut permeability and higher metabolic endotoxemia. Animal data suggest that both elements may impact muscle physiology, but human data corroborating the causality of the association between gut microbiota and muscle mass and strength are lacking. Mechanisms wherein the gut microbiota may alter anabolic resistance include an attenuation of gut-derived low-grade inflammation and/or the increased digestibility of protein-containing foods and consequent higher aminoacidemia, both in favour of muscle protein synthesis. This review focuses on the putative links between the gut microbiota and skeletal muscle in the context of sarcopenia. We also address the issue of plant protein digestibility because plant proteins are increasingly important from an environmental sustainability perspective, yet they are less efficient at stimulating muscle protein synthesis than animal proteins.

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