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1.
The relationships between sarcopenic skeletal muscle loss during ageing and macronutrient metabolism, obesity and onset of diabetes.
Welch, AA, Hayhoe, RPG, Cameron, D
The Proceedings of the Nutrition Society. 2020;(1):158-169
Abstract
Skeletal muscle is integral to the metabolism and utilisation of macronutrients; however, substantial muscle loss and morphological changes occur with ageing. These are associated with loss of muscle function and accelerate rapidly from the age of 60 years, leading to the conditions of sarcopenia and frailty. As the relationship between muscle ageing and macronutrient metabolism and utilisation has seen limited research to date, this review focuses on the interactions between skeletal muscle changes during ageing, metabolism and utilisation of fat, carbohydrates and overall energy expenditure.Skeletal muscle contributes less to resting energy expenditure during ageing, potentially contributing to onset of obesity from middle age. Age-related changes to skeletal muscle lead to glucose dysregulation, with consequent reduction in glycaemic control, increased insulin resistance and ultimately onset of type-2 diabetes. Recent studies indicate that high total fat and SFA intake are detrimental to skeletal muscle, while higher intakes of PUFA are protective. Age-associated changes in skeletal muscle may also reduce total fatty acid utilisation.In conclusion, further research is needed to understand the relationships between macronutrient metabolism and utilisation and age-related changes to skeletal muscle. No dietary recommendations exist specifically for skeletal muscle health during ageing, but we advise individuals to follow healthy eating guidelines, by consuming sufficient protein, fruit and vegetables, and limited SFA and to maintain physically active lifestyles. Clinicians responsible for managing type-2 diabetes need to be aware of growing evidence relating age-related skeletal muscle changes to diabetes onset and progression.
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2.
Nutritional Supplements to Support Resistance Exercise in Countering the Sarcopenia of Aging.
McKendry, J, Currier, BS, Lim, C, Mcleod, JC, Thomas, ACQ, Phillips, SM
Nutrients. 2020;(7)
Abstract
Skeletal muscle plays an indispensable role in metabolic health and physical function. A decrease in muscle mass and function with advancing age exacerbates the likelihood of mobility impairments, disease development, and early mortality. Therefore, the development of non-pharmacological interventions to counteract sarcopenia warrant significant attention. Currently, resistance training provides the most effective, low cost means by which to prevent sarcopenia progression and improve multiple aspects of overall health. Importantly, the impact of resistance training on skeletal muscle mass may be augmented by specific dietary components (i.e., protein), feeding strategies (i.e., timing, per-meal doses of specific macronutrients) and nutritional supplements (e.g., creatine, vitamin-D, omega-3 polyunsaturated fatty acids etc.). The purpose of this review is to provide an up-to-date, evidence-based account of nutritional strategies to enhance resistance training-induced adaptations in an attempt to combat age-related muscle mass loss. In addition, we provide insight on how to incorporate the aforementioned nutritional strategies that may support the growth or maintenance of skeletal muscle and subsequently extend the healthspan of older individuals.
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3.
Cardiac Cachexia: A Well-Known but Challenging Complication of Heart Failure.
Krysztofiak, H, Wleklik, M, Migaj, J, Dudek, M, Uchmanowicz, I, Lisiak, M, Kubielas, G, Straburzyńska-Migaj, E, Lesiak, M, Kałużna-Oleksy, M
Clinical interventions in aging. 2020;:2041-2051
Abstract
Heart failure (HF) is a common complication of various cardiac diseases, and its incidence constantly increases. This is caused mainly by aging of populations and improvement in the treatment of coronary artery disease. As HF patients age, they tend to develop comorbidities, creating new problems for health-care professionals. Sarcopenia, defined as the loss of muscle mass and function, and cachexia, defined as weight loss due to an underlying illness, are muscle wasting disorders of particular relevance in the heart failure population, but they go mostly unrecognized. The coexistence of chronic HF and metabolic disorders facilitates the development of cachexia. Cachexia, in turn, significantly worsens a patient's prognosis and quality of life. The mechanisms underlying cachexia have not been explained yet and require further research. Understanding its background is crucial in the development of treatment strategies to prevent and treat tissue wasting. There are currently no specific European guidelines or recommended therapy for cachexia treatment in HF ("cardiac cachexia").
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4.
Protein intake in older people : Why, how much and how?
Kiesswetter, E, Sieber, CC, Volkert, D
Zeitschrift fur Gerontologie und Geriatrie. 2020;(4):285-289
Abstract
The protein intake of older people has gained increasing scientific interest as a potential factor to delay the age-associated decline in muscle mass and consequently to counteract the development of sarcopenia. The skeletal muscle of older people seems less responsive to the anabolic stimulus of protein intake. Therefore, higher protein needs are discussed to overcome this anabolic resistance and to maintain muscle mass as far as possible. Besides the total amount of protein consumed, the distribution, quality and timing in relation to physical exercise are considered relevant; however, deriving clear recommendations for clinical practice is still difficult as positive results of protein intake on muscle metabolism found in experimental trials cannot simply be transferred to everyday conditions and randomized controlled trials often failed to show improvements in muscular outcomes related to protein supplementation. The effectiveness of protein supplementation may depend on functional resources of the older persons and the habitual protein intake. There is still a need for studies with well-defined protocols and populations to further elucidate the role of protein in the prevention and treatment of sarcopenia.
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5.
Muscle Mass Loss in the Older Critically Ill Population: Potential Therapeutic Strategies.
McKendry, J, Thomas, ACQ, Phillips, SM
Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition. 2020;(4):607-616
Abstract
Skeletal muscle plays a critical role in everyday life, and its age-associated reduction has severe health consequences. The pre-existing presence of sarcopenia, combined with anabolic resistance, protein undernutrition, and the pro-catabolic/anti-anabolic milieu induced by aging and exacerbated in critical care, may accelerate the rate at which skeletal muscle is lost in patients with critical illness. Advancements in intensive care unit (ICU)-care provision have drastically improved survival rates; therefore, attention can be redirected toward other significant issues affecting ICU patients (e.g., length of stay, days on ventilation, nosocomial disease development, etc.). Thus, strategies targeting muscle mass and function losses within an ICU setting are essential to improve patient-related outcomes. Notably, loading exercise and protein provision are the most compelling. Many older ICU patients seldom meet the recommended protein intake, and loading exercise is difficult to conduct in the ICU. Nevertheless, the incorporation of physical therapy (PT), neuromuscular electrical stimulation, and early mobilization strategies may be beneficial. Furthermore, a number of nutrition practices within the ICU have been shown to improve patient-related outcomes ((e.g., feeding strategy [i.e., oral, early enteral, or parenteral]), be hypocaloric (∼70%-80% energy requirements), and increase protein provision (∼1.2-2.5 g/kg/d)). The aim of this brief review is to discuss the dysregulation of muscle mass maintenance in an older ICU population and highlight the potential benefits of strategic nutrition practice, specifically protein, and PT within the ICU. Finally, we provide some general guidelines that may serve to counteract muscle mass loss in patients with critical illness.
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6.
Chronic Stress Contributes to Osteosarcopenic Adiposity via Inflammation and Immune Modulation: The Case for More Precise Nutritional Investigation.
Ilich, JZ, Gilman, JC, Cvijetic, S, Boschiero, D
Nutrients. 2020;(4)
Abstract
Chronic stress and low-grade chronic inflammation (LGCI) are key underlying factors formany diseases, including bone and body composition impairments. Objectives of this narrativereview were to examine the mechanisms by which chronic stress and LGCI may influenceosteosarcopenic adiposity (OSA) syndrome, originally named as ostoesarcopenic obesity (OSO).We also examined the crucial nutrients presumed to be affected by or cause of stress andinflammation and compared/contrasted them to those of our prehistoric ancestors. The evidenceshows that stress (particularly chronic) and its related inflammatory processes, contribute toosteoporosis, sarcopenia, and adiposity ultimately leading to OSA as a final and most derangedstate of body composition, commencing at the mesenchymal cell lineage disturbance. Thefoods/nutrients consumed by modern humans, as well as their altered lifestyle, also contribute tostress, LGCI and subsequently to OSA. The processes can also go in opposite direction when stressand inflammation impact nutritional status, particularly some micronutrients' levels. Whilenutritional management of body composition and LGCI have been studied, the nutrients (and theirquantities) most affected by stressors and those which may act toward the alleviation of stressfulstate, ultimately leading to better body composition outcomes, need to be elucidated.
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7.
Docosahexaenoic Acid, a Potential Treatment for Sarcopenia, Modulates the Ubiquitin-Proteasome and the Autophagy-Lysosome Systems.
Lee, JH, Jeon, JH, Lee, MJ
Nutrients. 2020;(9)
Abstract
One of the characteristic features of aging is the progressive loss of muscle mass, a nosological syndrome called sarcopenia. It is also a pathologic risk factor for many clinically adverse outcomes in older adults. Therefore, delaying the loss of muscle mass, through either boosting muscle protein synthesis or slowing down muscle protein degradation using nutritional supplements could be a compelling strategy to address the needs of the world's aging population. Here, we review the recently identified properties of docosahexaenoic acid (DHA). It was shown to delay muscle wasting by stimulating intermediate oxidative stress and inhibiting proteasomal degradation of muscle proteins. Both the ubiquitin-proteasome and the autophagy-lysosome systems are modulated by DHA. Collectively, growing evidence indicates that DHA is a potent pharmacological agent that could improve muscle homeostasis. Better understanding of cellular proteolytic systems associated with sarcopenia will allow us to identify novel therapeutic interventions, such as omega-3 polyunsaturated fatty acids, to treat this disease.
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8.
Defining sarcopenia: some caveats and challenges.
Sanchez-Rodriguez, D, Marco, E, Cruz-Jentoft, AJ
Current opinion in clinical nutrition and metabolic care. 2020;(2):127-132
Abstract
PURPOSE OF REVIEW To summarize the latest advances and caveats in defining sarcopenia and discuss the implications of the most recent worldwide initiatives which are trying to harmonize the definition. RECENT FINDINGS The evolution over time of the definitions of sarcopenia is discussed, with a focus on the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) definition and the Sarcopenia Definitions and Outcomes Consortium (SDOC) conference. The EWGSOP2 and the SDOC agree on the overall concept of sarcopenia, which involves both impaired function (low muscle strength) and structural damage (low muscle mass/quality). However, physical performance is considered as a diagnostic criterion (EWGSOP), a severity grading assessment (EWGSOP2) or an outcome (SDOC) pending on the definition used. Muscle strength has been recognized as the best predictor of health outcomes. Muscle mass alone, as part of the definition of cachexia, sarcopenia and malnutrition, is a nondefining parameter. Furthermore, there is a lack of precision in measurement techniques and variability of the cut-off points in defining it. SUMMARY We discuss the relationship of sarcopenia with cachexia, malnutrition and frailty, and the areas that are hampering agreement. We summarize key scientific evidence, consider future study of this nutrition-related disease and raise concern about the need for a universal definition of sarcopenia.
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9.
Sarcopenia during COVID-19 lockdown restrictions: long-term health effects of short-term muscle loss.
Kirwan, R, McCullough, D, Butler, T, Perez de Heredia, F, Davies, IG, Stewart, C
GeroScience. 2020;(6):1547-1578
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Abstract
The COVID-19 pandemic is an extraordinary global emergency that has led to the implementation of unprecedented measures in order to stem the spread of the infection. Internationally, governments are enforcing measures such as travel bans, quarantine, isolation, and social distancing leading to an extended period of time at home. This has resulted in reductions in physical activity and changes in dietary intakes that have the potential to accelerate sarcopenia, a deterioration of muscle mass and function (more likely in older populations), as well as increases in body fat. These changes in body composition are associated with a number of chronic, lifestyle diseases including cardiovascular disease (CVD), diabetes, osteoporosis, frailty, cognitive decline, and depression. Furthermore, CVD, diabetes, and elevated body fat are associated with greater risk of COVID-19 infection and more severe symptomology, underscoring the importance of avoiding the development of such morbidities. Here we review mechanisms of sarcopenia and their relation to the current data on the effects of COVID-19 confinement on physical activity, dietary habits, sleep, and stress as well as extended bed rest due to COVID-19 hospitalization. The potential of these factors to lead to an increased likelihood of muscle loss and chronic disease will be discussed. By offering a number of home-based strategies including resistance exercise, higher protein intakes and supplementation, we can potentially guide public health authorities to avoid a lifestyle disease and rehabilitation crisis post-COVID-19. Such strategies may also serve as useful preventative measures for reducing the likelihood of sarcopenia in general and in the event of future periods of isolation.
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Assessment of muscle mass in critically ill patients: role of the sarcopenia index and images studies.
Lopez-Ruiz, A, Kashani, K
Current opinion in clinical nutrition and metabolic care. 2020;(5):302-311
Abstract
PURPOSE OF REVIEW Sarcopenia is a progressive generalized decline in skeletal muscle mass, strength, and function. This condition is highly prevalent in critically ill patients and is associated with poor outcomes in the ICU. In this review, we describe the use, evidence, and limitations of the most common validated imaging studies used to assess muscle mass in ICU, and we provide an overview of the benefits of using the sarcopenia index [(serum creatinine/serum cystatin C) × 100]) in the ICU. RECENT FINDINGS Currently, the determination of muscle mass using anthropometric measurements and serum biomarkers is unreliable. Several new techniques, including a dual-energy X-ray absorptiometry, computed tomography scan, ultrasonography, and bioimpedance analysis, have been studied and validated for the diagnosis and prognosis of sarcopenia in the ICU. However, these techniques are often not accessible for the majority of critically ill patients. The sarcopenia index constitutes an accurate method to diagnose sarcopenia, predict ICU outcomes, and nutritional status in critically ill patients. SUMMARY Diagnosis of sarcopenia has substantial implications in ICU patients. Choosing the correct test to identify patients who may need preventive or therapeutic support for this condition will favorably impact ICU outcomes.