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 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.

scholarly journals Accumulation of intramuscular toxic lipids, a link between fat mass accumulation and sarcopenia

OCL ◽  
2019 ◽  
Vol 26 ◽  
pp. 24 ◽  
Author(s):  
Frederic Capel ◽  
Alexandre Pinel ◽  
Stéphane Walrand
Keyword(s):  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Intramyocellular Lipids ◽  
Age Related ◽  
Degradation Rates ◽  
Lipid Species ◽  
Risk Of Falls ◽  
Muscle Protein Metabolism ◽  
And Function

Aging is characterized by a loss in muscle mass and function, which is defined as sarcopenia. It weakens individuals by increasing the risk of falls and altering their quality of life. The loss of muscle mass results from the age-related impairment of the anabolic effect of nutrients and insulin, which normally increase and decrease muscle protein synthesis and degradation rates respectively. Alterations in muscle protein metabolism have been related to the accumulation of body fat and intramyocellular lipids. In particular, some lipid species such as ceramides or diacylglycerols have been described as inhibitors of the insulin signaling pathway in different models. Accumulation of these molecules in skeletal muscle could result from a lowered buffering capacity of circulating fatty acids by adipose tissue in response to the meal, a reduction of mitochondrial oxidative capacities or chronic inflammation. However, some nutritional strategies have been identified to limit or prevent the accumulation of lipotoxic metabolites and to improve the sensitivity of muscle to nutrients or insulin.

scholarly journals Characterising the muscle anabolic potential of dairy, meat and plant-based protein sources in older adults

2017 ◽  
Vol 77 (1) ◽  
pp. 20-31 ◽  
Author(s):  
Stefan H. M. Gorissen ◽  
Oliver C. Witard
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Amino Acid ◽  
Muscle Mass ◽  
Dietary Protein ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Amino Acid Profile ◽  
Protein Sources ◽  
Age Related

The age-related loss of skeletal muscle mass and function is caused, at least in part, by a reduced muscle protein synthetic response to protein ingestion. The magnitude and duration of the postprandial muscle protein synthetic response to ingested protein is dependent on the quantity and quality of the protein consumed. This review characterises the anabolic properties of animal-derived and plant-based dietary protein sources in older adults. While approximately 60 % of dietary protein consumed worldwide is derived from plant sources, plant-based proteins generally exhibit lower digestibility, lower leucine content and deficiencies in certain essential amino acids such as lysine and methionine, which compromise the availability of a complete amino acid profile required for muscle protein synthesis. Based on currently available scientific evidence, animal-derived proteins may be considered more anabolic than plant-based protein sources. However, the production and consumption of animal-derived protein sources is associated with higher greenhouse gas emissions, while plant-based protein sources may be considered more environmentally sustainable. Theoretically, the lower anabolic capacity of plant-based proteins can be compensated for by ingesting a greater dose of protein or by combining various plant-based proteins to provide a more favourable amino acid profile. In addition, leucine co-ingestion can further augment the postprandial muscle protein synthetic response. Finally, prior exercise or n-3 fatty acid supplementation have been shown to sensitise skeletal muscle to the anabolic properties of dietary protein. Applying one or more of these strategies may support the maintenance of muscle mass with ageing when diets rich in plant-based protein are consumed.

scholarly journals Association of Protein Intake in Three Meals with Muscle Mass in Healthy Young Subjects: A Cross-Sectional Study

Nutrients ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 612 ◽  
Author(s):  
Jun Yasuda ◽  
Mai Asako ◽  
Takuma Arimitsu ◽  
Satoshi Fujita
Keyword(s):  
Muscle Mass ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Cross Sectional Study ◽  
Fat Free Mass ◽  
Intake Rate ◽  
Young Population ◽  
Cross Sectional ◽  
Young Subjects

Protein intake of >0.24 g/kg of body weight (BW) at a single meal is necessary to maximize muscle protein synthesis in a young population. However, the association between the protein intake rate for three meals and muscle mass in the young population has not been evaluated. We hypothesized that a protein intake of >0.24 g/kg BW at all three meals is effective for maintaining muscle mass. Therefore, we cross-sectionally examined the association between protein intake at all three meals with muscle mass in 266 healthy young subjects (aged 21.4 ± 2.4 years). Subjects were divided into the AP group, which achieved protein intake >0.24 g/kg BW at all three meals; and the NP group, which did not. We calculated total fat-free mass (FFM) and appendicular fat-free mass (AppFFM) with dual-energy X-ray absorptiometry, and the percentage of total FFM (TotalFFM%) and appendicular FFM (AppFFM%) were calculated as the percentage of BW (%BW). We demonstrated that TotalFFM% (77.0 ± 0.5 vs. 75.2 ± 0.4%, p = 0.008) and AppFFM% (34.7 ± 0.3 vs. 34.1 ± 0.2%, p = 0.058) were higher in the AP than in the NP group. This finding suggests that achieving protein intake of >0.24 g/kg BW at all three meals is important for muscle mass maintenance in young populations.

Aging, exercise, and muscle protein metabolism

2009 ◽  
Vol 106 (6) ◽  
pp. 2040-2048 ◽  
Author(s):  
René Koopman ◽  
Luc J. C. van Loon
Keyword(s):  
Physical Activity ◽  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Food Intake ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
The Elderly ◽  
Age Related

Aging is accompanied by a progressive loss of skeletal muscle mass and strength, leading to the loss of functional capacity and an increased risk of developing chronic metabolic disease. The age-related loss of skeletal muscle mass is attributed to a disruption in the regulation of skeletal muscle protein turnover, resulting in an imbalance between muscle protein synthesis and degradation. As basal (fasting) muscle protein synthesis rates do not seem to differ substantially between the young and elderly, many research groups have started to focus on the muscle protein synthetic response to the main anabolic stimuli, i.e., food intake and physical activity. Recent studies suggest that the muscle protein synthetic response to food intake is blunted in the elderly. The latter is now believed to represent a key factor responsible for the age-related decline in skeletal muscle mass. Physical activity and/or exercise stimulate postexercise muscle protein accretion in both the young and elderly. However, the latter largely depends on the timed administration of amino acids and/or protein before, during, and/or after exercise. Prolonged resistance type exercise training represents an effective therapeutic strategy to augment skeletal muscle mass and improve functional performance in the elderly. The latter shows that the ability of the muscle protein synthetic machinery to respond to anabolic stimuli is preserved up to very old age. Research is warranted to elucidate the interaction between nutrition, exercise, and the skeletal muscle adaptive response. The latter is needed to define more effective strategies that will maximize the therapeutic benefits of lifestyle intervention in the elderly.

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 Dietary protein, exercise, ageing and physical inactivity: interactive influences on skeletal muscle proteostasis

2020 ◽  
pp. 1-12
Author(s):  
Colleen S. Deane ◽  
Isabel A. Ely ◽  
Daniel J. Wilkinson ◽  
Kenneth Smith ◽  
Bethan E. Phillips ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Dietary Protein ◽  
Protein Intake ◽  
Physical Inactivity ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Muscle Blood Flow ◽  
Regulatory Protein ◽  
Anabolic Resistance ◽  
Short Period

Dietary protein is a pre-requisite for the maintenance of skeletal muscle mass; stimulating increases in muscle protein synthesis (MPS), via essential amino acids (EAA), and attenuating muscle protein breakdown, via insulin. Muscles are receptive to the anabolic effects of dietary protein, and in particular the EAA leucine, for only a short period (i.e. about 2–3 h) in the rested state. Thereafter, MPS exhibits tachyphylaxis despite continued EAA availability and sustained mechanistic target of rapamycin complex 1 signalling. Other notable characteristics of this ‘muscle full’ phenomenon include: (i) it cannot be overcome by proximal intake of additional nutrient signals/substrates regulating MPS; meaning a refractory period exists before a next stimulation is possible, (ii) it is refractory to pharmacological/nutraceutical enhancement of muscle blood flow and thus is not induced by muscle hypo-perfusion, (iii) it manifests independently of whether protein intake occurs in a bolus or intermittent feeding pattern, and (iv) it does not appear to be dependent on protein dose per se. Instead, the main factor associated with altering muscle full is physical activity. For instance, when coupled to protein intake, resistance exercise delays the muscle full set-point to permit additional use of available EAA for MPS to promote muscle remodelling/growth. In contrast, ageing is associated with blunted MPS responses to protein/exercise (anabolic resistance), while physical inactivity (e.g. immobilisation) induces a premature muscle full, promoting muscle atrophy. It is crucial that in catabolic scenarios, anabolic strategies are sought to mitigate muscle decline. This review highlights regulatory protein turnover interactions by dietary protein, exercise, ageing and physical inactivity.

scholarly journals Dietary protein and exercise training in ageing

2010 ◽  
Vol 70 (1) ◽  
pp. 104-113 ◽  
Author(s):  
René Koopman
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Exercise Training ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Human Subjects ◽  
The Elderly ◽  
Age Related

Ageing is accompanied by a progressive loss of skeletal muscle mass and strength, leading to the loss of functional capacity and an increased risk for developing chronic metabolic diseases such as diabetes. The age-related loss of skeletal muscle mass results from a chronic disruption in the balance between muscle protein synthesis and degradation. As basal muscle protein synthesis rates are likely not different between healthy young and elderly human subjects, it was proposed that muscles from older adults lack the ability to regulate the protein synthetic response to anabolic stimuli, such as food intake and physical activity. Indeed, the dose–response relationship between myofibrillar protein synthesis and the availability of essential amino acids and/or resistance exercise intensity is shifted down and to the right in elderly human subjects. This so-called ‘anabolic resistance’ represents a key factor responsible for the age-related decline in skeletal muscle mass. Interestingly, long-term resistance exercise training is effective as a therapeutic intervention to augment skeletal muscle mass, and improves functional performance in the elderly. The consumption of different types of proteins, i.e. protein hydrolysates, can have different stimulatory effects on muscle protein synthesis in the elderly, which may be due to their higher rate of digestion and absorption. Current research aims to elucidate the interactions between nutrition, exercise and the skeletal muscle adaptive response that will define more effective strategies to maximise the therapeutic benefits of lifestyle interventions in the elderly.

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.

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