Effect of nutritional interventions and resistance exercise on aging muscle mass and strength

Synergistic Effects of Omega-3 Fatty Acids and Physical Activity on Oxidative Stress Markers and Antioxidant Mechanisms in Aged Rats

BACKGROUND

Aging induces degenerative processes in the body, contributing to the onset of various age-associated diseases that affect the population. Inadequate dietary habits and low physical activity are major contributors to increased morbidity during aging. This study aimed to investigate the combined effects of omega-3 fatty acid supplementation and physical activity on the markers of oxidative stress and antioxidant defense mechanisms in aged male Wistar rats (23-24 months).

METHODS

The rats were randomly divided into four experimental groups: a sedentary control (placebo, no exercise), a trained (placebo and moderate-intensity graded aerobic exercise; Ex), and two trained groups supplemented with low (160 mg/kg of body weight; O1 + Ex) and high (320 mg/kg of body weight; O2 + Ex) doses of omega-3 fatty acids. The biochemical and functional parameters related to sarcopenia and the markers of oxidative stress were measured in blood and gastrocnemius muscle.

RESULTS

The results demonstrated dose-dependent, synergistic effects of omega-3 fatty acid supplementation and physical activity. The higher dose (320 mg/kg of body weight) improved plasma antioxidant capacity (TEAC, +21.01%, p < 0.01) and GPx activity (+78.05%, p < 0.05) while reducing CAT activity in erythrocytes (-19.92%, p < 0.05), likely as an adaptive stress response. Combined interventions also normalized cholesterol levels, improved the functional parameters of sarcopenia (stride length, +14.82%, p < 0.001), and enhanced antioxidant protection in aged rats.

CONCLUSIONS

These findings highlight the potential of combining omega-3 fatty acid supplementation and physical activity to counteract aging-related degenerative changes. Further research is needed to elucidate the underlying mechanisms and evaluate the long-term benefits of these strategies in aging populations.

Potential of Fatty Acids in Treating Sarcopenia: A Systematic Review

This paper presents a systematic review of studies investigating the effects of fatty acid supplementation in potentially preventing and treating sarcopenia. PubMed, Embase, and Web of Science databases were searched using the keywords 'fatty acid' and 'sarcopenia'. Results: A total of 14 clinical and 11 pre-clinical (including cell and animal studies) studies were included. Of the 14 clinical studies, 12 used omega-3 polyunsaturated fatty acids (PUFAs) as supplements, 1 study used ALA and 1 study used CLA. Seven studies combined the use of fatty acid with resistant exercises. Fatty acids were found to have a positive effect in eight studies and they had no significant outcome in six studies. The seven studies that incorporated exercise found that fatty acids had a better impact on elderlies. Four animal studies used novel fatty acids including eicosapentaenoic acid, trans-fatty acid, and olive leaf extraction as interventions. Three animal and four cell experiment studies revealed the possible mechanisms of how fatty acids affect muscles by improving regenerative capacity, reducing oxidative stress, mitochondrial and peroxisomal dysfunctions, and attenuating cell death. Conclusion: Fatty acids have proven their value in improving sarcopenia in pre-clinical experiments. However, current clinical studies show controversial results for its role on muscle, and thus the mechanisms need to be studied further. In the future, more well-designed randomized controlled trials are required to assess the effectiveness of using fatty acids in humans.

Impact of process and composition of formulas for elderly on in vitro digestion using the dynamic DIDGI® model

Due to the lower efficiency of the elderly digestion system, new formulations are needed in order to increase the bioaccessibility of macronutrients. The aim of the work was to evaluate the effect of the process of protein sources production using either liquid (F2) vs spray dried milk proteins (F1/F3) and the source of lipids (vegetable oil (F1) vs mix of vegetable oil + bovine milk cream (F2/F3)) ingredients on the macronutrient digestion of three experimental elderly formulas. The dynamic in vitro digestion model DIDGI®^, was adapted to simulate the digestive conditions of the elderly. An exhaustive review of the literature was carried out in order to simulate as closely as possible the elderly digestive parameters and constituted the starting point towards a consensus in vitro digestion model that will be proposed soon by the INFOGEST scientific network. The three experimental formulas (F1/F2/F3) differing by the composition and process applied were submitted to the DIDGI® dynamic in vitro digestion over four hours using parameters adapted to the elderly. The three formulas were compared in terms of proteolysis and lipolysis. A slight impact of the process (liquid vs spray-dried) on the degree of proteolysis at the end of digestion was observed with 50.8% for F2 compared to 56.8% for F1 and 52.9% for F3 with<5% of difference between the 3 formulas. Concerning the degree of lipolysis, the addition of bovine cream led to a lesser extent of lipolysis with 63.7 and 60.2% for F2 and F3 respectively versus 66.3% for F1 (containing only vegetable oil). Our results highlighted the beneficial input of the milk fat with a higher level of phospholipids and a lower ω6/ω3 PUFA ratio and can be a good alternative to the use of the vegetable fat in drinks for elderly people.

Sarcopenic obesity is associated with coffee intake in elderly Koreans

This study assessed the association between sarcopenic obesity (S+O+) and coffee intake inelderly Koreans. This study obtained data from the Korea National Health and Nutrition Examination Survey (KNHANES, 2008-2011), a cross-sectional and nationally representative survey conducted by the Korean Centers for Disease Control and Prevention. Of the 2,661 participants included in this study, there was a significant difference between 5.861 (95% CI 2.024-16.971) in less than one cup of coffee, and 6.245 (95% CI 2.136-18.260) in one cup of coffee, and 4.323 (95% CI 1.457-12.824) in two cups of coffee compared to three or more than cups of coffee. In contrast, in the case of sarcopenia or obesity only (S+O- or S-O+), no significant difference was found in any model. The results suggest that the elderly who consume less than one cup of coffee per day had a greater risk of S+O+ than those who consume more than three cups per day. Furthermore, there was an association between coffee intake and sarcopenia but not with obesity. Therefore, coffee intake may have prevented musculoskeletal loss in these patients.

Effects of Omega-3 Supplementation Alone and Combined with Resistance Exercise on Skeletal Muscle in Older Adults: A Systematic Review and Meta-Analysis

Sarcopenia negatively affects skeletal muscle mass and function in older adults. Omega-3 (ω-3) fatty acid supplementation, with or without resistance exercise training (RET), is suggested to play a role as a therapeutic component to prevent or treat the negative effects of sarcopenia. A systematic review and meta-analysis were conducted on the impact of ω-3 fatty acid supplementation with or without RET on measures of muscle mass and function in older adults (≥55 y). The data sources included SPORTDiscus, PubMed, and Medline. All the study types involving ω-3 fatty acid supplementation on measures of muscle mass and function in older adults (without disease) were included. The mean differences (MDs) or standardized mean differences (SMDs) with 95% confidence intervals were calculated and pooled effects assessed. Sixteen studies (1660 females, 778 males) met our inclusion criteria and were included in the meta-analysis. ω-3 fatty acid supplementation did not impact lean tissue mass (SMD 0.09 [-0.10, 0.28]). Benefits were observed for lower body strength (SMD 0.54 [0.33, 0.75]), timed-up-and-go (MD 0.29 [0.23, 0.35]s), and 30-s sit-to-stand performance (MD 1.93 [1.59, 2.26] repetitions) but not walking performance (SMD -0.01 [-0.10, 0.07]) or upper body strength (SMD 0.05 [-0.04, 0.13]). Supplementing with ω-3 fatty acids may improve the lower-body strength and functionality in older adults.

Effects of Different Resistance Exercise Forms on Body Composition and Muscle Strength in Overweight and/or Obese Individuals: A Systematic Review and Meta-Analysis

Purpose

This study is a systematic review and meta-analysis to determine the effects of different forms of resistance training on body composition and muscle strength in overweight and/or obese people.

Method

Only randomized controlled trials (RCTs) were included by searching relevant databases such as a web of science, PubMed, and EBSCO, with search dates up to September 30, 2021. These trials performed resistance exercise training in overweight and/or obese people, and outcome indicators included evaluation of body composition and muscle strength, among other relevant indicators. The Cochrane evaluation tool was used to evaluate the methodological quality of the included literature, and statistical analysis was performed using the R analysis software.

Results

Fifteen studies, 18 trials, with a total of 669 participants meeting eligibility criteria were included in the final analysis, which included three resistance training types (own body weight, resistance bands, and free weight). The results showed that resistance bands improved body fat (BF; SMD −0.79, 95% CI −1.25 to −0.33, I2 = 0%) in overweight or obese people better than other resistance training types. Own body weight resistance training was better for increasing skeletal muscle mass in overweight or obese people (SMD 0.48, 95% CI 0.04–0.92, I2 = 0%). In addition, for muscle strength increase, although resistance exercise was shown to improve muscle strength, there was no significant difference between the three exercise forms compared.

Conclusion

Resistance bands can improve body composition by reducing BF. Resistance bands can improve body composition by reducing BF, while it is more effective in increasing muscle mass and own body weight. Therefore, for overweight and obese people, resistance bands resistance exercise can be taken for fat loss, and resistance exercise for own body weight for further muscle gain and maintenance of muscle mass, so as to achieve the purpose of improving body composition.

Relationship Between Dietary Omega-3 and Omega-6 Polyunsaturated Fatty Acids Level and Sarcopenia. A Meta-Analysis of Observational Studies

Objective: This study investigates the relationship between dietary omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) levels and sarcopenia. Methods: A comprehensive literature search in the databases of PubMed, Web of Science, and Embase (up to July 2021) were conducted to identify the observational studies on the relationship between dietary omega-3 and omega-6 PUFAs level and sarcopenia. The pooled odds ratio (OR) of sarcopenia for the highest vs. lowest dietary omega-3 and omega-6 PUFAs level and the standard mean difference (SMD) of dietary omega-3 and omega-6 PUFAs levels for sarcopenia vs. control subjects were calculated. Results: A total of six studies were identified in this meta-analysis. The overall multi-variable adjusted OR showed that dietary omega-3 PUFAs level was inversely associated with sarcopenia (OR = 0.41, 95% CI: 0.26-0.65; P = 0.0001). Moreover, the overall combined SMD showed that the dietary omega-3 PUFAs level in sarcopenia was lower than that in control subjects (SMD = -0.19, 95% CI: -0.32 to -0.07; P = 0.002). With regard to dietary omega-6 PUFAs level, the overall multi-variable adjusted OR suggested no significant relationship between dietary omega-6 PUFAs level and sarcopenia (OR = 0.64, 95% CI: 0.33-1.24; P = 0.19). However, the overall combined SMD showed that the dietary omega-6 PUFAs level in sarcopenia was slightly lower than that in control subjects (SMD = -0.15, 95% CI: -0.27 to -0.02; P = 0.02). Conclusion: Our results suggested that the dietary omega-3 PUFAs level was inversely associated with sarcopenia. However, current evidence is still insufficient to demonstrate the definite relationship between dietary omega-6 PUFAs levels and sarcopenia. More well-designed prospective cohort studies with the dietary omega-3/omega-6 PUFAs ratio are still needed.

Age-Specific Association Between Handgrip Strength and Nutritional Quality in Korean Men: A Nationwide Cross-Sectional Study

This study aimed to determine the potential association between handgrip strength and nutritional quality in Korean men aged ≥20 years using data from the Korea National Health and Nutrition Examination Survey 2016 to 2018. This population-based cross-sectional study included 5,748 men aged ≥20 years. A dietary intake survey was performed using the 24-hr dietary recall method. Nutritional quality was examined using the Index of Nutritional Quality (INQ) score. A high INQ score reflected poor nutritional quality, with insufficient intake of many nutrients. Multivariate linear regression was used to determine the association between handgrip strength and INQ scores after adjusting for other covariates. The intake of carbohydrates, fiber, calcium, and vitamins B2 and C was significantly positively associated with a higher quartile for handgrip strength for those aged ≥65 years (all p < .01). A significant inverse association was found between the quartiles of handgrip strength and INQ scores among men aged ≥65 years after adjusting for all covariates (β = -0.26, p < .01). This association was not found among those aged <65 years (p = .25). The age-specific association between handgrip strength and nutritional quality underscores the importance of public policies that promote sufficient and comprehensive nutrient intake among older adults. Handgrip strength may be useful in clinical practice as a simple and cost-effective tool for screening for nutritional quality in older adults.

Alcalase Potato Protein Hydrolysate-PPH902 Enhances Myogenic Differentiation and Enhances Skeletal Muscle Protein Synthesis under High Glucose Condition in C2C12 Cells

Sarcopenia is an aging associated disorder involving skeletal muscle atrophy and a reduction in muscle strength, and there are no pharmaceutical interventions available thus far. Moreover, conditions such as hyperglycaemia are known to further intensify muscle degradation. Therefore, novel strategies to attenuate skeletal muscle loss are essential to enhance muscle function and thereby improve the quality of life in diabetic individuals. In this study, we have investigated the efficiency of a potato peptide hydrolysate PPH902 for its cytoprotective effects in skeletal muscle cells. PPH902 treatment in C2C12 cells showed the dose-dependent activation of the Akt/mTOR signalling pathway that is involved in skeletal myogenesis. According to Western blotting analysis, PPH902 induced the phosphorylation of Akt, mTOR proteins and induced the myogenic differentiation of C2C12 myoblasts in a differentiation medium. The phosphorylation myogenic transcription factor Foxo3A was also found to be increased in the cells treated with PPH902. In addition, treatment with PPH902 ameliorated the high glucose induced reduction in cell viability in a dose-dependent manner. Moreover, the number of myotubes in a differentiation medium reduced upon high glucose challenge, but treatment with PPH902 increased the number of differentiated myotubes. Further, the phosphorylations of AMPK and mitochondrial-related transcription factors such as PGC-1α were suppressed upon high glucose challenge but PPH902 treatment restored the protein levels. We demonstrate, for the first time, that a specific potato peptide has a therapeutic effect against sarcopenia. In addition, PPH902 improved the myogenic differentiation and their mitochondrial biogenesis and further improved myogenic protein and inhibited muscle protein degradation in C2C12 cells challenged under a high glucose condition.

Current Evidence and Possible Future Applications of Creatine Supplementation for Older Adults

Sarcopenia, defined as age-related reduction in muscle mass, strength, and physical performance, is associated with other age-related health conditions such as osteoporosis, osteosarcopenia, sarcopenic obesity, physical frailty, and cachexia. From a healthy aging perspective, lifestyle interventions that may help overcome characteristics and associated comorbidities of sarcopenia are clinically important. One possible intervention is creatine supplementation (CR). Accumulating research over the past few decades shows that CR, primarily when combined with resistance training (RT), has favourable effects on aging muscle, bone and fat mass, muscle and bone strength, and tasks of physical performance in healthy older adults. However, research is very limited regarding the efficacy of CR in older adults with sarcopenia or osteoporosis and no research exists in older adults with osteosarcopenia, sarcopenic obesity, physical frailty, or cachexia. Therefore, the purpose of this narrative review is (1) to evaluate and summarize current research involving CR, with and without RT, on properties of muscle and bone in older adults and (2) to provide a rationale and justification for future research involving CR in older adults with osteosarcopenia, sarcopenic obesity, physical frailty, or cachexia.

Comparison of the effect of resistance training on the body compositions of different women groups: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

This study attempts to investigate whether simple resistance training (RT) exerts different effects on the body composition of different women groups.

EVIDENCE ACQUISITION

Relevant articles from PubMed and Web of Science databases were searched and simultaneously screened by two authors. Twenty-three randomized controlled trials are included. The qualities were evaluated by the Cochrane bias risk evaluation tool. Data about sample size, Means and SD of FM, BF %, FFM and MM from original articles were extracted and processed by Reviewer Manager 5.3 software.

EVIDENCE SYNTHESIS

For women with postmenopausal, RT can significantly reduce their BF% and FM, and increase their FFM; while for women with premenopausal, it can only obviously reduce their BF%. RT can significantly reduce the FM and BF% of women with overweight/obese and increase their FFM, however, it has no significant effect on women with non-overweight/obese. RT can substantially and positively affect the FM, BF% and FFM of women with sedentary, and can significantly increase the FFM of women with non-sedentary.

CONCLUSIONS

The effect of RT on women's body composition varies across different subgroups with different physiological characteristics. As a consequence, it is more recommended to use RT as a training method for women with postmenopausal, overweight/obese or sedentary, which can achieve a better effect of improving body composition.

Utilization of Hydroxyl-Methyl Butyrate, Leucine, Glutamine and Arginine Supplementation in Nutritional Management of Sarcopenia-Implications and Clinical Considerations for Type 2 Diabetes Mellitus Risk Modulation

While onset characteristics may vary, sarcopenia gradually develops over time as a result of the aging process, leading to muscle loss, disturbance of the muscle to fat ratio, and a variety of negative symptoms undermining the wellbeing, quality of life, and lifespan in the aging population globally. There is evidence that sarcopenia may be a cause and consequence of type 2 diabetes mellitus (T2DM) in the aging population. The importance of nutritional management in the prevention and/or deceleration of sarcopenia is critical, with the main focus placed on the amount and quality of protein intake. Significant efforts are being made towards the development of medical nutrition therapies involving certain amino acids and amino compounds, as well as their combinations, for the improvement in muscle strength, muscle function and protein synthesis. This may reduce hospitalization times and hasten the recovery of patients with sarcopenia. The administration of protocols with varying dose and frequencies, as well as their efficacy, is being investigated. In the work herein, we present and evaluate data derived from human trials regarding the utilization of hydroxyl-methyl butyrate (HMB), L-leucine (Leu), L-glutamine (Gln) and L-arginine (Arg) supplementation for optimal management of sarcopenia in geriatric patients, a topic of significant clinical nutrition interest which may have important implications in T2DM status.

Reduced dietary omega-3 fatty acids intake is associated with sarcopenia in elderly patients with type 2 diabetes: a cross-sectional study of KAMOGAWA-DM cohort study

Omega-3 fatty acids intake is important to maintain muscle mass. However, the relationship between omega-3 fatty acids intake and sarcopenia in elderly patients with type 2 diabetes has been unclear. We used the brief-type self-administered diet history questionnaire for the assessment of habitual food and nutrient intake. Body composition of patients was evaluated using bioimpedance analysis. To investigate the effect of energy intake on the presence of sarcopenia, we performed logistic regression analyses. Among the patients, 45 patients (13.2%) were diagnosed as sarcopenia. Patients with sarcopenia were aged [74.2 (5.7) vs 71.4 (5.9) years, p = 0.003] and lower body mass index [21.2 (3.5) vs 24.3 (4.6) kg/m², p<0.001] than those without. In addition, omega-3 fatty acids intake of patients with sarcopenia was lower than that without [2.6 (1.0) vs 3.0 (1.2) kcal/day, p = 0.046]. Omega-3 fatty acids intake was negatively associated with the presence of sarcopenia (odds ratio: 0.29, 95% confidence interval: 0.14-0.60, p<0.001) after adjusting for age, sex, exercise, smoking status, diabetes duration, hemoglobin A1c, energy intake, protein intake, fat intake and omega-3 fatty acids intake. Omega-3 fatty acids intake was negatively associated with the presence of sarcopenia in elderly patients with type 2 diabetes.

A focused review of myokines as a potential contributor to muscle hypertrophy from resistance-based exercise

PURPOSE

Resistance exercise induces muscle growth and is an important treatment for age-related losses in muscle mass and strength. Myokines are hypothesized as a signal conveying physiological information to skeletal muscle, possibly to "fine-tune" other regulatory pathways. While myokines are released from skeletal muscle following contraction, their role in increasing muscle mass and strength in response to resistance exercise or training is not established. Recent research identified both local and systemic release of myokines after an acute bout of resistance exercise. However, it is not known whether myokines with putative anabolic function are mechanistically involved in producing muscle hypertrophy after resistance exercise. Further, nitric oxide (NO), an important mediator of muscle stem cell activation, upregulates the expression of certain myokine genes in skeletal muscle.

METHOD

In the systemic context of complex hypertrophic signaling, this review: (1) summarizes literature on several well-recognized, representative myokines with anabolic potential; (2) explores the potential mechanistic role of myokines in skeletal muscle hypertrophy; and (3) identifies future research required to advance our understanding of myokine anabolism specifically in skeletal muscle.

RESULT

This review establishes a link between myokines and NO production, and emphasizes the importance of considering systemic release of potential anabolic myokines during resistance exercise as complementary to other signals that promote hypertrophy.

CONCLUSION

Investigating adaptations to resistance exercise in aging opens a novel avenue of interdisciplinary research into myokines and NO metabolites during resistance exercise, with the longer-term goal to improve muscle health in daily living, aging, and rehabilitation.

A pilot study on the effects of DHA/EPA-enriched phospholipids on aerobic and anaerobic exercises in mice

DHA/EPA-PL andl-carnitine had significant effects on aerobic exercise, while astaxanthin improved anaerobic exercise. The possible mechanism involved carbohydrate and lipid metabolism, mitochondrial respiratory chain and tricarboxylic acid cycle.

Nutritional and Pharmacological Interventions to Expedite Recovery Following Muscle-Damaging Exercise in Older Adults: A Narrative Review of the Literature

Exercise-induced muscle damage (EIMD) manifests as muscle soreness, inflammation, and reductions in force generating capacity that can last for several days after exercise. The ability to recover and repair damaged tissues following EIMD is impaired with age, with older adults (≥50 years old) experiencing a slower rate of recovery than their younger counterparts do for the equivalent exercise bout. This narrative review discusses the literature examining the effect of nutritional or pharmacological supplements taken to counter the potentially debilitating effects of EIMD in older adults. Studies have assessed the effects of nonsteroidal anti-inflammatory drugs, vitamin C and/or E, or higher protein diets on recovery in older adults. Each intervention showed some promise for attenuating EIMD, but, overall, there is a paucity of available data in this population, and more studies are required to determine the influence of nutrition or pharmacological interventions on EIMD in older adults.

Fatty Acid Profile and Antioxidant Status Fingerprint in Sarcopenic Elderly Patients: Role of Diet and Exercise

Plasma fatty acids (FAs) and oxidant status contribute to the etiology of sarcopenia in the elderly concurring to age-related muscle loss and elderly frailty through several mechanisms including changes in FA composition within the sarcolemma, promotion of chronic low-grade inflammation, and insulin resistance. The aim of this study was to determine the FA profile and pro-antioxidant status in sarcopenic frail elderly patients enrolled in a nutritional and physical activity program and to evaluate their correlation with clinical markers. Moreover, the possible changes, produced after a short-term clinical protocol, were evaluated. Plasma and erythrocyte FA composition and pro-antioxidant status were analyzed in sarcopenic elderly subjects recruited for the randomized clinical study and treated with a placebo or dietary supplement, a personalized diet, and standardized physical activity. Subjects were tested before and after 30 days of treatment. Pearson correlations between biochemical parameters and patients’ characteristics at recruitment indicate interesting features of sarcopenic status such as negative correlation among the plasma FA profile, age, and physical characteristics. Physical activity and dietetic program alone for 30 days induced a decrease of saturated FA concentration with a significant increase of dihomo-gamma-linolenic acid. Supplementation plus physical activity induced a significant decrease of linoleic acid, omega-6 polyunsaturated FAs, and an increase of stearic and oleic acid concentration. Moreover, glutathione reductase activity, which is an indicator of antioxidant status, significantly increased in erythrocytes. Changes over time between groups indicate significant differences for saturated FAs, which suggest that the amino acid supplementation restores FA levels that are consumed during physical activity. A relationship between FA and clinical/metabolic status revealed unique correlations and a specific metabolic and lipidomic fingerprint in sarcopenic elderly. The results indicate the positive beneficial role of supplementation and physical activity on plasma FA status and the antioxidant system as a co-adjuvant approach in sarcopenic, frail, elderly patients.

Effectiveness of Creatine Supplementation on Aging Muscle and Bone: Focus on Falls Prevention and Inflammation

Sarcopenia, defined as the age-related decrease in muscle mass, strength and physical performance, is associated with reduced bone mass and elevated low-grade inflammation. From a healthy aging perspective, interventions which overcome sarcopenia are clinically relevant. Accumulating evidence suggests that exogenous creatine supplementation has the potential to increase aging muscle mass, muscle performance, and decrease the risk of falls and possibly attenuate inflammation and loss of bone mineral. Therefore, the purpose of this review is to: (1) summarize the effects of creatine supplementation, with and without resistance training, in aging adults and discuss possible mechanisms of action, (2) examine the effects of creatine on bone biology and risk of falls, (3) evaluate the potential anti-inflammatory effects of creatine and (4) determine the safety of creatine supplementation in aging adults.

Supplements with purported effects on muscle mass and strength

PURPOSE

Several supplements are purported to promote muscle hypertrophy and strength gains in healthy subjects, or to prevent muscle wasting in atrophying situations (e.g., ageing or disuse periods). However, their effectiveness remains unclear.

METHODS

This review summarizes the available evidence on the beneficial impacts of several popular supplements on muscle mass or strength.

RESULTS

Among the supplements tested, nitrate and caffeine returned sufficient evidence supporting their acute beneficial effects on muscle strength, whereas the long-term consumption of creatine, protein and polyunsaturated fatty acids seems to consistently increase or preserve muscle mass and strength (evidence level A). On the other hand, mixed or unclear evidence was found for several popular supplements including branched-chain amino acids, adenosine triphosphate, citrulline, β-Hydroxy-β-methylbutyrate, minerals, most vitamins, phosphatidic acid or arginine (evidence level B), weak or scarce evidence was found for conjugated linoleic acid, glutamine, resveratrol, tribulus terrestris or ursolic acid (evidence level C), and no evidence was found for other supplements such as ornithine or α-ketoglutarate (evidence D). Of note, although most supplements appear to be safe when consumed at typical doses, some adverse events have been reported for some of them (e.g., caffeine, vitamins, α-ketoglutarate, tribulus terrestris, arginine) after large intakes, and there is insufficient evidence to determine the safety of many frequently used supplements (e.g., ornithine, conjugated linoleic acid, ursolic acid).

CONCLUSION

 In summary, despite their popularity, there is little evidence supporting the use of most supplements, and some of them have been even proven ineffective or potentially associated with adverse effects.

High-fat diet suppresses the positive effect of creatine supplementation on skeletal muscle function by reducing protein expression of IGF-PI3K-AKT-mTOR pathway

High-fat (HF) diets in combination with sedentary lifestyle represent one of the major public health concerns predisposing to obesity and diabetes leading to skeletal muscle atrophy, decreased fiber diameter and muscle mass with accumulation of fat tissue resulting in loss of muscle strength. One strategy to overcome the maleficent effects of HF diet is resistance training, a strategy used to improve muscle mass, reverting the negative effects on obesity-related changes in skeletal muscle. Together with resistance training, supplementation with creatine monohydrate (CrM) in the diet has been used to improve muscle mass and strength. Creatine is a non-essential amino acid that is directly involved in the cross-bridge cycle providing a phosphate group to ADP during the initiation of muscle contraction. Besides its antioxidant and anti-inflammatory effects CrM also upregulates IGF-1 resulting in hyperthophy with an increase in muscle function. However, it is unknown whether CrM supplementation during resistance training would revert the negative effects of high-fat diet on the muscle performance. During 8 weeks we measured muscle performance to climb a 1.1m and 80° ladder with increasing load on trained rats that had received standard diet or high-fat diet, supplemented or not with CrM. We observed that the CrM supplementation up-regulated IGF-1 and phospho-AKT protein levels, suggesting an activation of the IGF1-PI3K-Akt/PKB-mTOR pathway. Moreover, despite the CrM supplementation, HF diet down-regulated several proteins of the IGF1-PI3K-Akt/PKB-mTOR pathway, suggesting that diet lipid content is crucial to maintain or improve muscle function during resistance training.

Omega-3 supplementation with resistance training does not improve body composition or lower biomarkers of inflammation more so than resistance training alone in older men

The purpose of this study was to evaluate the effectiveness of 3.0 g/d of omega-3 fatty acid (eicosapentaenoic acid and docosahexaenoic acid) supplementation combined with progressive resistance training to improve body composition and lower inflammatory cytokines in older men when compared to placebo and resistance training. We hypothesized that completing a 12-week omega-3 supplementation period along with whole body resistance exercise (3 times/wk) would result in a significantly greater improvement in lean tissue mass as well as a significant decrease in interleukin-6 and tumor necrosis factor-α when compared to placebo. A total of 23 older men (≥65 years old) were randomized to an omega-3 supplementation group (n = 11) or placebo group (n = 12), and all the participants completed the same whole body progressive resistance training program. Baseline and 12-week data collection included body composition, muscle strength, functional ability, and inflammatory cytokines. Results indicated a significant main effect for time (all P < .05) for percent body fat (-2.5%), lean tissue mass (+1.1%), lumbar bone mineral density (+1.1%), hip bone mineral content (+1.1%), chest press strength (+31%), leg press strength (+37%), timed-up-and-go (-6.6%), and 6-minute walk distance (+4.5%) from baseline to post 12 weeks. No significant effects were noted for the 2 inflammatory cytokines measured (P > .05). We conclude that progressive resistance training exercise is an excellent method to enhance parameters of body composition, skeletal muscle strength, and functional ability in older men, whereas omega-3 supplementation did nothing to enhance these parameters or influence inflammatory biomarkers.

Skeletal muscle performance and ageing

The world population is ageing rapidly. As society ages, the incidence of physical limitations is dramatically increasing, which reduces the quality of life and increases healthcare expenditures. In western society, ~30% of the population over 55 years is confronted with moderate or severe physical limitations. These physical limitations increase the risk of falls, institutionalization, co-morbidity, and premature death. An important cause of physical limitations is the age-related loss of skeletal muscle mass, also referred to as sarcopenia. Emerging evidence, however, clearly shows that the decline in skeletal muscle mass is not the sole contributor to the decline in physical performance. For instance, the loss of muscle strength is also a strong contributor to reduced physical performance in the elderly. In addition, there is ample data to suggest that motor coordination, excitation-contraction coupling, skeletal integrity, and other factors related to the nervous, muscular, and skeletal systems are critically important for physical performance in the elderly. To better understand the loss of skeletal muscle performance with ageing, we aim to provide a broad overview on the underlying mechanisms associated with elderly skeletal muscle performance. We start with a system level discussion and continue with a discussion on the influence of lifestyle, biological, and psychosocial factors on elderly skeletal muscle performance. Developing a broad understanding of the many factors affecting elderly skeletal muscle performance has major implications for scientists, clinicians, and health professionals who are developing therapeutic interventions aiming to enhance muscle function and/or prevent mobility and physical limitations and, as such, support healthy ageing.

Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis

The loss of muscle mass and strength with aging results in significant functional impairment. Creatine supplementation has been used in combination with resistance training as a strategy for increasing lean tissue mass and muscle strength in older adults, but results across studies are equivocal. We conducted a systematic review and meta-analysis of randomized controlled trials of creatine supplementation during resistance training in older adults with lean tissue mass, chest press strength, and leg press strength as outcomes by searching PubMed and SPORTDiscus databases. Twenty-two studies were included in our meta-analysis with 721 participants (both men and women; with a mean age of 57–70 years across studies) randomized to creatine supplementation or placebo during resistance training 2–3 days/week for 7–52 weeks. Creatine supplementation resulted in greater increases in lean tissue mass (mean difference =1.37 kg [95% CI =0.97–1.76]; p<0.00001), chest press strength (standardized mean difference [SMD] =0.35 [0.16–0.53]; p=0.0002), and leg press strength (SMD =0.24 [0.05–0.43]; p=0.01). A number of mechanisms exist by which creatine may increase lean tissue mass and muscular strength. These are included in a narrative review in the discussion section of this article. In summary, creatine supplementation increases lean tissue mass and upper and lower body muscular strength during resistance training of older adults, but potential mechanisms by which creatine exerts these positive effects have yet to be evaluated extensively.

The Combination of Physical Exercise with Muscle-Directed Antioxidants to Counteract Sarcopenia: A Biomedical Rationale for Pleiotropic Treatment with Creatine and Coenzyme Q10

Sarcopenia represents an increasing public health risk due to the rapid aging of the world's population. It is characterized by both low muscle mass and function and is associated with mobility disorders, increased risk of falls and fractures, loss of independence, disabilities, and increased risk of death. Despite the urgency of the problem, the development of treatments for sarcopenia has lagged. Increased reactive oxygen species (ROS) production and decreased antioxidant (AO) defences seem to be important factors contributing to muscle impairment. Studies have been conducted to verify whether physical exercise and/or AOs could prevent and/or delay sarcopenia through a normalization of the etiologically relevant ROS imbalance. Despite the strong rationale, the results obtained were contradictory, particularly with regard to the effects of the tested AOs. A possible explanation might be that not all the agents included in the general heading of "AOs" could fulfill the requisites to counteract the complex series of events causing/accelerating sarcopenia: the combination of the muscle-directed antioxidants creatine and coenzyme Q10 with physical exercise as a biomedical rationale for pleiotropic prevention and/or treatment of sarcopenia is discussed.

Special nutrition intervention is required for muscle protective efficacy of physical exercise in elderly people at highest risk of sarcopenia

Progressive loss of muscle mass and strength is a physiological consequence of aging, and without interventions, it usually deteriorates into sarcopenia. In this study, the hypothesis that combined special nutritional-physiotherapeutical intervention to prevent or reverse this biological deterioration in elderly people was tested. The effects of the regular resistance muscle training (PT, n = 17) alone and the combined exercise + special nutrition therapy containing whey protein and vitamin D (PT + NT, n = 17) were monitored for 3 months in 34 elderly patients (12 men and 22 women; mean age: 66.47 years) randomly distributed into two groups at a long-term care facility. Physical exercise alone did not result in significant improvement in skeletal muscle mass or strength, whereas combined intervention significantly increased the muscle strength (22.51 ± 2.35 vs. 24.54 ± 2.65, [Formula: see text] ± SEM, kg, p = 0.027). When therapeutic responses to the intervention were compared, a significant advantage of PT + NT over PT was found. The same trend was found when the non-significant post-therapeutic alterations (χ² test) of the distribution of normal vs. pre-sarcopenic + sarcopenic conditions within the two groups were compared. Combined intervention (PT + NT) is necessary for the efficient protection of the musculature in the high-risk elderly patients.

Ratio of dietary ω-3 and ω-6 fatty acids-independent determinants of muscle mass-in hemodialysis patients with diabetes

OBJECTIVE

ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) are essential nutrients in the human diet and possibly affect muscle mass. We evaluated the association between the dietary ratios of ω-3 and ω-6 PUFAs and muscle mass, indicated as skeletal muscle mass (SMM) and appendicular skeletal muscle mass (ASM), in patients with diabetes undergoing hemodialysis (HD).

METHODS

In this cross-sectional study, data on 69 patients with diabetes who underwent standard HD therapy were analyzed. For estimating muscle mass, anthropometric and bioelectrical impedance analyses were conducted following dialysis. In addition, routine laboratory and 3-d dietary data were obtained. The adequate intake (AI) cut-off for ω-3 PUFAs was 1.6 g/d and 1.1 g/d for male and female patients, respectively.

RESULTS

The average age of the participants was 63.0 ± 10.4 y. The mean ratios of ω-3/ω-6 PUFA intake, ω-6/ω-3 PUFA intake, SMM, and ASM of the patients were 0.13 ± 0.07, 9.4 ± 6.4, 24.6 ± 5.4 kg, and 18.3 ± 4.6 kg, respectively. Patients who had AI of ω-3 PUFAs had significantly higher SMM and ASM than did their counterparts. Linear and stepwise multivariable adjustment analyses revealed that insulin resistance and the ω-6/ω-3 PUFA ratio were the independent deleterious determinants of ASM normalized to height in HD patients.

CONCLUSIONS

Patients with AI of ω-3 PUFAs had total-body SMM and ASM that were more appropriate. A higher dietary ratio of ω-6/ω-3 PUFAs was associated with reduced muscle mass in HD patients.

Whey protein, amino acids, and vitamin D supplementation with physical activity increases fat-free mass and strength, functionality, and quality of life and decreases inflammation in sarcopenic elderly

BACKGROUND

Interventions to attenuate the adverse effects of age-related loss of skeletal muscle and function include increased physical activity and nutritional supplementation.

OBJECTIVE

This study tested the hypothesis that nutritional supplementation with whey protein (22 g), essential amino acids (10.9 g, including 4 g leucine), and vitamin D [2.5 μg (100 IU)] concurrent with regular, controlled physical activity would increase fat-free mass, strength, physical function, and quality of life, and reduce the risk of malnutrition in sarcopenic elderly persons.

DESIGN

A total of 130 sarcopenic elderly people (53 men and 77 women; mean age: 80.3 y) participated in a 12-wk randomized, double-blind, placebo-controlled supplementation trial. All participants concurrently took part in a controlled physical activity program. We examined body composition with dual-energy X-ray absorptiometry, muscle strength with a handgrip dynamometer, and blood biochemical indexes of nutritional and health status, and evaluated global nutritional status, physical function, and quality of life before and after the 12 wk of intervention.

RESULTS

Compared with physical activity and placebo, supplementation plus physical activity increased fat-free mass (1.7-kg gain, P < 0.001), relative skeletal muscle mass (P = 0.009), android distribution of fat (P = 0.021), handgrip strength (P = 0.001), standardized summary scores for physical components (P = 0.030), activities of daily living (P = 0.001), mini nutritional assessment (P = 0.003), and insulin-like growth factor I (P = 0.002), and lowered C-reactive protein (P = 0.038).

CONCLUSION

Supplementation with whey protein, essential amino acids, and vitamin D, in conjunction with age-appropriate exercise, not only boosts fat-free mass and strength but also enhances other aspects that contribute to well-being in sarcopenic elderly. This trial was registered at clinicaltrials.gov as NCT02402608.

SARC-F: a symptom score to predict persons with sarcopenia at risk for poor functional outcomes

BACKGROUND

A brief, inexpensive screening test for sarcopenia would be helpful for clinicians and their patients. To screen for persons with sarcopenia, we developed a simple five-item questionnaire (SARC-F) based on cardinal features or consequences of sarcopenia.

METHODS

We investigated the utility of SARC-F in the African American Health (AAH) study, Baltimore Longitudinal Study of Aging (BLSA), and National Health and Nutrition Examination Survey (NHANES). Internal consistency reliability for SARC-F was determined using Cronbach's alpha. We evaluated SARC-F factorial validity using principal components analysis and criterion validity by examining its association with exam-based indicators of sarcopenia. Construct validity was examined using cross-sectional and longitudinal differences among those with high (≥4) vs. low (<4) SARC-F scores for mortality and health outcomes.

RESULTS

SARC-F exhibited good internal consistency reliability and factorial, criterion, and construct validity. AAH participants with SARC-F scores ≥ 4 had more Instrumental Activity of Daily Living (IADL) deficits, slower chair stand times, lower grip strength, lower short physical performance battery scores, and a higher likelihood of recent hospitalization and of having a gait speed of <0.8 m/s. SARC-F scores ≥ 4 in AAH also were associated with 6 year IADL deficits, slower chair stand times, lower short physical performance battery scores, having a gait speed of <0.8 m/s, being hospitalized recently, and mortality. SARC-F scores ≥ 4 in the BLSA cohort were associated with having more IADL deficits and lower grip strength (both hands) in cross-sectional comparisons and with IADL deficits, lower grip strength (both hands), and mortality at follow-up. NHANES participants with SARC-F scores ≥ 4 had slower 20 ft walk times, had lower peak force knee extensor strength, and were more likely to have been hospitalized recently in cross-sectional analyses.

CONCLUSIONS

The SARC-F proved internally consistent and valid for detecting persons at risk for adverse outcomes from sarcopenia in AAH, BLSA, and NHANES.

[Nutritional status in patients with chronic pancreatitis]

Chronic pancreatitis (CP) is an inflammatory disease of the pancreas, accompanied by damage to the functioning parenchyma and ducts to develop irreversible structural changes (fibrosis, calcification) and irreparable loss of the endocrine and exocrine functions of this organ. Maldigestion is a typical outcome of CP of any etiology with a long-term history. Fat malabsorption is considered as a basis for malnutrition in patients with CP. The severity of malnutrition in patients with CP correlates with three major pathogenetic factors: primary nutrient deficiency, pancreatic maldigestion and secondary malabsorption syndrome (nutrient loss), hypermetabolism that is caused by an inflammatory process in the pancreas and that determines the severity of the disease. Malnutrition in patients with CP is not just a complication of this disease, but has an important impact on its course. Patients with severe malnutrition are noted to have the significantly lower activity of pancreatic enzymes in the duodenal contents, feces, and blood, which is correlated with the smaller blood amount of total protein and albumin.

Metformin Treatment Prevents Sedentariness Related Damages in Mice

Metformin (METF), historical antihyperglycemic drug, is a likely candidate for lifespan extension, treatment and prevention of sedentariness damages, insulin resistance, and obesity. Skeletal muscle is a highly adaptable tissue, capable of hypertrophy response to resistance training and of regeneration after damage. Aims of this work were to investigate METF ability to prevent sedentariness damage and to enhance skeletal muscle function. Sedentary 12-week-old C57BL/6 mice were treated with METF (250 mg/kg per day, in drinking water) for 60 days. METF role on skeletal muscle differentiation was studied in vitro using murine C2C12 myoblasts. Muscular performance evaluation revealed that METF enhanced mice physical performance (Estimated VO2max). Biochemical analyses of hepatic and muscular tissues indicated that in liver METF increased AMPK and CAMKII signaling. In contrast, METF inactivated ERKs, the principal kinases involved in hepatic stress. In skeletal muscle, METF activated AKT, key kinase in skeletal muscle mass maintenance. In in vitro studies, METF did not modify the C2C12 proliferation capacity, while it positively influenced the differentiation process and myotube maturation. In conclusion, our novel results suggest that METF has a positive action not only on the promotion of healthy aging but also on the prevention of sedentariness damages.

Ratio of Dietary n-6/n-3 Polyunsaturated Fatty Acids Independently Related to Muscle Mass Decline in Hemodialysis Patients

Background

n-3 polyunsaturated fatty acids (PUFAs) might be useful nutritional strategy for treating patients with sarcopenia. We evaluated the effect of the intake of dietary n-3 PUFAs on the skeletal muscle mass (SMM), appendicular skeletal muscle mass (ASM), and its determinants in patients receiving standard hemodialysis (HD) treatment for the management of end stage renal disease.

Methods

In this cross-sectional study, data of 111 HD patients were analyzed. Anthropometric and bioelectrical impedance measurements used to estimate the muscle mass were performed the day of dialysis immediately after the dialysis session. Routine laboratory and 3-day dietary data were also collected. The cutoff value of adequate intake (AI) for both n-3 PUFAs and alpha-linolenic acid (ALA) was 1.6 g/day and 1.1 g/day for men and women, respectively.

Results

The mean age, mean dietary n-3 PUFAs intake, ALA intake, ratio of n-6/n-3 PUFAs intake, SMM, and ASM of patients were 61.4 ± 10.4 years, 2.0 ± 1.3 g/day, 1.5 ± 1.0 g/day, 9.5 ± 6.7 g/day, 23.9 ± 5.5 kg, and 17.5 ± 4.5 kg, respectively. A higher SMM and ASM significantly observed in patients who achieved an AI of n-3 PUFAs. Similar trends appeared to be observed among those patients who achieved the AI of ALA, but the difference was not significantly, except for ASM (P = 0.047). No relevant differences in demographics, laboratory and nutritional parameters were observed, regardless of whether the patients achieved an AI of n-3 PUFAs. Multivariate analysis showed that the BMI and equilibrated Kt/V were independent determinants of the muscle mass. Moreover, the ratio of n-6/n-3 PUFAs was an independent risk determinant of reduced ASM in HD patients.

Conclusion

Patients with an AI of n-3 PUFAs had better total-body SMM and ASM. A higher dietary ratio of n-6/n-3 PUFAs seemed to be associated with a reduced muscle mass in HD patients.

Detection of muscle wasting in patients with chronic heart failure using C-terminal agrin fragment: results from the Studies Investigating Co-morbidities Aggravating Heart Failure (SICA-HF)

AIMS

Skeletal muscle wasting affects 20% of patients with chronic heart failure and has serious implications for their activities of daily living. Assessment of muscle wasting is technically challenging. C-terminal agrin-fragment (CAF), a breakdown product of the synaptically located protein agrin, has shown early promise as biomarker of muscle wasting. We sought to investigate the diagnostic properties of CAF in muscle wasting among patients with heart failure.

METHODS AND RESULTS

We assessed serum CAF levels in 196 patients who participated in the Studies Investigating Co-morbidities Aggravating Heart Failure (SICA-HF). Muscle wasting was identified using dual-energy X-ray absorptiometry (DEXA) in 38 patients (19.4%). Patients with muscle wasting demonstrated higher CAF values than those without (125.1 ± 59.5 pmol/L vs. 103.8 ± 42.9 pmol/L, P = 0.01). Using receiver operating characteristics (ROC), we calculated the optimal CAF value to identify patients with muscle wasting as >87.5 pmol/L, which had a sensitivity of 78.9% and a specificity of 43.7%. The area under the ROC curve was 0.63 (95% confidence interval 0.56-0.70). Using simple regression, we found that serum CAF was associated with handgrip (R = - 0.17, P = 0.03) and quadriceps strength (R = - 0.31, P < 0.0001), peak oxygen consumption (R = - 0.5, P < 0.0001), 6-min walk distance (R = - 0.32, P < 0.0001), and gait speed (R = - 0.2, P = 0.001), as well as with parameters of kidney and liver function, iron metabolism and storage.

CONCLUSION

CAF shows good sensitivity for the detection of skeletal muscle wasting in patients with heart failure. Its assessment may be useful to identify patients who should undergo additional testing, such as detailed body composition analysis. As no other biomarker is currently available, further investigation is warranted.

Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial

Protein supplementation in combination with resistance training may increase muscle mass and muscle strength in elderly subjects. The objective of this study was to assess the influence of post-exercise protein supplementation with collagen peptides v. placebo on muscle mass and muscle function following resistance training in elderly subjects with sarcopenia. A total of fifty-three male subjects (72·2 (sd 4·68) years) with sarcopenia (class I or II) completed this randomised double-blind placebo-controlled study. All the participants underwent a 12-week guided resistance training programme (three sessions per week) and were supplemented with either collagen peptides (treatment group (TG)) (15 g/d) or silica as placebo (placebo group (PG)). Fat-free mass (FFM), fat mass (FM) and bone mass (BM) were measured before and after the intervention using dual-energy X-ray absorptiometry. Isokinetic quadriceps strength (IQS) of the right leg was determined and sensory motor control (SMC) was investigated by a standardised one-leg stabilisation test. Following the training programme, all the subjects showed significantly higher (P<0·01) levels for FFM, BM, IQS and SMC with significantly lower (P<0·01) levels for FM. The effect was significantly more pronounced in subjects receiving collagen peptides: FFM (TG +4·2 (sd 2·31) kg/PG +2·9 (sd 1·84) kg; P<0·05); IQS (TG +16·5 (sd 12·9) Nm/PG +7·3 (sd 13·2) Nm; P<0·05); and FM (TG -5·4 (sd 3·17) kg/PG -3·5 (sd 2·16) kg; P<0·05). Our data demonstrate that compared with placebo, collagen peptide supplementation in combination with resistance training further improved body composition by increasing FFM, muscle strength and the loss in FM.

Loquat leaf extract enhances myogenic differentiation, improves muscle function and attenuates muscle loss in aged rats

A main characteristic of aging is the debilitating, progressive and generalized impairment of biological functions, resulting in an increased vulnerability to disease and death. Skeletal muscle comprises approximately 40% of the human body; thus, it is the most abundant tissue. At the age of 30 onwards, 0.5‑1% of human muscle mass is lost each year, with a marked acceleration in the rate of decline after the age of 65. Thus, novel strategies that effectively attenuate skeletal muscle loss and enhance muscle function are required to improve the quality of life of older subjects. The aim of the present study was to determine whether loquat (Eriobotrya japonica) leaf extract (LE) can prevent the loss of skeletal muscle function in aged rats. Young (5-month-old) and aged (18‑19-month-old) rats were fed LE (50 mg/kg/day) for 35 days and the changes in muscle mass and strength were evaluated. The age‑associated loss of grip strength was attenuated, and muscle mass and muscle creatine kinase (CK) activity were enhanced following the administration of LE. Histochemical analysis also revealed that LE abrogated the age‑associated decrease in cross‑sectional area (CSA) and decreased the amount of connective tissue in the muscle of aged rats. To investigate the mode of action of LE, C2C12 murine myoblasts were used to evaluate the myogenic potential of LE. The expression levels of myogenic proteins (MyoD and myogenin) and functional myosin heavy chain (MyHC) were measured by western blot analysis. LE enhanced MyoD, myogenin and MyHC expression. The changes in the expression of myogenic genes corresponded with an increase in the activity of CK, a myogenic differentiation marker. Finally, LE activated the Akt/mammalian target of rapamycin (mTOR) signaling pathway, which is involved in muscle protein synthesis during myogenesis. These findings suggest that LE attenuates sarcopenia by promoting myogenic differentiation and subsequently promoting muscle protein synthesis.

Strategic creatine supplementation and resistance training in healthy older adults

Creatine supplementation in close proximity to resistance training may be an important strategy for increasing muscle mass and strength; however, it is unknown whether creatine supplementation before or after resistance training is more effective for aging adults. Using a double-blind, repeated measures design, older adults (50–71 years) were randomized to 1 of 3 groups: creatine before (CR-B: n = 15; creatine (0.1 g/kg) immediately before resistance training and placebo (0.1 g/kg cornstarch maltodextrin) immediately after resistance training), creatine after (CR-A: n = 12; placebo immediately before resistance training and creatine immediately after resistance training), or placebo (PLA: n = 12; placebo immediately before and immediately after resistance training) for 32 weeks. Prior to and following the study, body composition (lean tissue, fat mass; dual-energy X-ray absorptiometry) and muscle strength (1-repetition maximum leg press and chest press) were assessed. There was an increase over time for lean tissue mass and muscle strength and a decrease in fat mass (p < 0.05). CR-A resulted in greater improvements in lean tissue mass (Δ 3.0 ± 1.9 kg) compared with PLA (Δ 0.5 ± 2.1 kg; p < 0.025). Creatine supplementation, independent of the timing of ingestion, increased muscle strength more than placebo (leg press: CR-B, Δ 36.6 ± 26.6 kg; CR-A, Δ 40.8 ± 38.4 kg; PLA, Δ 5.6 ± 35.1 kg; chest press: CR-B, Δ 15.2 ± 13.0 kg; CR-A, Δ 15.7 ± 12.5 kg; PLA, Δ 1.9 ± 14.7 kg; p < 0.025). Compared with resistance training alone, creatine supplementation improves muscle strength, with greater gains in lean tissue mass resulting from post-exercise creatine supplementation.

Prevention and optimal management of sarcopenia: a review of combined exercise and nutrition interventions to improve muscle outcomes in older people

The growing recognition of sarcopenia, the age-related loss of skeletal muscle mass and function, has highlighted the need to understand more about its etiology. Declines in muscle mass and strength are expected aspects of aging, but there is significant variability between individuals in rates of loss. Although some of these differences can be explained by fixed factors, such as sex, much of the remaining variation is unexplained. This has led to increasing interest in the influence of adult lifestyle, particularly in the effects of modifiable factors such as physical activity and diet, and in identifying intervention opportunities both to prevent and manage sarcopenia. A number of trials have examined the separate effects of increased exercise or dietary supplementation on muscle mass and physical performance of older adults, but less is known about the extent to which benefits of exercise training could be enhanced when these interventions are combined. In a comprehensive review of the literature, we consider 17 studies of older adults (≥65 years) in which combined nutrition and exercise interventions were used to increase muscle strength and/or mass, and achieve improvements in physical performance. The studies were diverse in terms of the participants included (nutritional status, degree of physical frailty), supplementation strategies (differences in nutrients, doses), exercise training (type, frequency), as well as design (duration, setting). The main message is that enhanced benefits of exercise training, when combined with dietary supplementation, have been shown in some trials – indicating potential for future interventions, but that existing evidence is inconsistent. Further studies are needed, particularly of exercise training combined with dietary strategies that increase intakes of a range of nutrients, as well as bioactive non-nutrients, to provide the evidence on which public health and clinical recommendations can be based.

Aged Muscle Demonstrates Fiber-Type Adaptations in Response to Mechanical Overload, in the Absence of Myofiber Hypertrophy, Independent of Satellite Cell Abundance

Although sarcopenia, age-associated loss of muscle mass and strength, is neither accelerated nor exacerbated by depletion of muscle stem cells, satellite cells, we hypothesized that adaptation in sarcopenic muscle would be compromised. To test this hypothesis, we depleted satellite cells with tamoxifen treatment of Pax7(CreER)-DTA mice at 4 months of age, and 20 months later subjected the plantaris muscle to 2 weeks of mechanical overload. We found myofiber hypertrophy was impaired in aged mice regardless of satellite cell content. Even in the absence of growth, vehicle-treated mice mounted a regenerative response, not apparent in tamoxifen-treated mice. Further, myonuclear accretion occurred in the absence of growth, which was prevented by satellite cell depletion, demonstrating that myonuclear addition is insufficient to drive myofiber hypertrophy. Satellite cell depletion increased extracellular matrix content of aged muscle that was exacerbated by overload, potentially limiting myofiber growth. These results support the idea that satellite cells regulate the muscle environment, and that their loss during aging may contribute to fibrosis, particularly during periods of remodeling. Overload induced a fiber-type composition improvement, independent of satellite cells, suggesting that aged muscle is very responsive to exercise-induced enhancement in oxidative capacity, even with an impaired hypertrophic response.

Clinical effectiveness of protein and amino acid supplementation on building muscle mass in elderly people: a meta-analysis

OBJECTIVE

A major reason for the loss of mobility in elderly people is the gradual loss of lean body mass known as sarcopenia. Sarcopenia is associated with a lower quality of life and higher healthcare costs. The benefit of strategies that include nutritional intervention, timing of intervention, and physical exercise to improve muscle loss unclear as finding from studies investigating this issue have been inconsistent. We have performed a systematic review and meta-analysis to assess the ability of protein or amino acid supplementation to augment lean body mass or strength of leg muscles in elderly patients.

METHODS

Nine studies met the inclusion criteria of being a prospective comparative study or randomized controlled trial (RCT) that compared the efficacy of an amino acid or protein supplement intervention with that of a placebo in elderly people (≥ 65 years) for the improvement of lean body mass (LBM), leg muscle strength or reduction associated with sarcopenia.

RESULTS

The overall difference in mean change from baseline to the end of study in LBM between the treatment and placebo groups was 0.34 kg which was not significant (P = 0.386). The overall differences in mean change from baseline in double leg press and leg extension were 2.14 kg (P = 0.748) and 2.28 kg (P = 0.265), respectively, between the treatment group and the placebo group.

CONCLUSIONS

These results indicate that amino acid/protein supplements did not increase lean body mass gain and muscle strength significantly more than placebo in a diverse elderly population.

The effectiveness of leucine on muscle protein synthesis, lean body mass and leg lean mass accretion in older people: a systematic review and meta-analysis

In the present study, we performed a meta-analysis to assess the ability of leucine supplementation to increase the muscle protein fraction synthetic rate and to augment lean body mass or leg lean mass in elderly patients. A literature search was conducted on Medline, Cochrane, EMBASE and Google Scholar databases up to 31 December 2013 for clinical trials that investigated the administration of leucine as a nutrient that affects muscle protein metabolism and muscle mass in elderly subjects. The included studies were randomised controlled trials. The primary outcome for the meta-analysis was the protein fractional synthetic rate. Secondary outcomes included lean body mass and leg lean mass. A total of nine studies were included in the meta-analysis. The results showed that the muscle protein fractional synthetic rate after intervention significantly increased in the leucine group compared with the control group (pooled standardised difference in mean changes 1·08, 95% CI 0·50, 1·67; P< 0·001). No difference was found between the groups in relation to lean body mass (pooled standardised difference in mean changes 0·18, 95% CI - 0·18, 0·54; P= 0·318) or leg lean mass (pooled standardised difference in mean changes 0·006, 95% CI - 0·32, 0·44; P= 0·756). These findings suggest that leucine supplementation is useful to address the age-related decline in muscle mass in elderly individuals, as it increases the muscle protein fractional synthetic rate.

Body composition changes were related to nutrient intakes in elderly men but elderly women had a higher prevalence of sarcopenic obesity in a population of Korean adults

In this study, we examined the relationship between sarcopenic obesity (SO) and nutrition status, according to sex in Korean adults who were 60 years or older. Body composition was categorized as SO, sarcopenic nonobesity, nonsarcopenic obesity, and nonsarcopenic nonobesity. Obesity was defined by body mass index. Sarcopenia was defined as an appendicular skeletal muscle mass divided by weight (Wt) of less than 1 SD below the sex-specific mean for young adults. Subjects included 1433 subjects (658 men and 775 women) who were 60 years or older and who participated in the fifth Korea National Health and Nutritional Examination Survey 2010. Sarcopenic obesity was more prevalent in women (31.3%) than in men (19.6%). Individuals with SO had significantly higher fasting insulin, homeostasis model assessment of insulin resistance (male: 3.2 ± 1.4, female: 3.4 ± 2.1), and triglycerides (male: 167.3 ± 90.6 mg/dL, female: 160.7 ± 85.0 mg/dL). High-density lipoprotein was under the normal criteria (50 mg/dL) in women. Intake of nutrients associated with muscle loss (protein, vitamin D, calcium, and vitamin C) was significantly different among the male but not the female groups. Although protein intake was normal, calcium and vitamin D intakes were insufficient in all groups. In conclusion, body composition changes were related to nutrient intakes in elderly (60 years or older) men but not elderly women. Women had a higher prevalence of SO than did men, suggesting that early nutritional intervention in elderly women may help them address age-associated body composition changes.

Dietary pattern classifications with nutrient intake and body composition changes in Korean elderly

BACKGROUND/OBJECTIVES

The body composition changes in aging increased the risk of metabolic disorder. Recent dietary studies have increasingly focused on the correlations between dietary patterns and chronic diseases to overcome the limitations of traditional single-nutrient studies because nutrients in food have complex relations that interact.

SUBJECTS/METHODS

This study was conducted to classify a dietary pattern among Korean elderly using cluster analysis and to explore the relationships between dietary patterns and body composition changes in Korean elderly aged 65 years or older. The study subjects (n = 1,435) were individuals who participated in the Korean National Health Examination and Nutrition Survey (KNHANES) in 2011.

RESULTS

There were three dietary patterns derived by cluster analysis in this study: 'Traditional Korean' (37.49% of total population), 'Meat and Alcohol' (19.65%) and 'Westernized Korean' (42.86%). The (1) 'Traditional Korean' pattern was characterized by high consumptions of white rice and low protein, low fat, and low milk products, while (2) 'Westernized Korean' pattern ate a Korean-style diet base with various foods such as noodles, bread, eggs and milk, (3) 'Meat and Alcohol' pattern had high consumptions of meat and alcohol. In body composition changes, compared with the 'Traditional Korean' pattern, the 'Meat & alcohol' pattern was associated with a 50% increased risk of having elevated BMI (kg/m²), 'Westernized Korean' pattern was associated with a 74% increased abnormality of ASM/Wt (kg) by logistics analysis. Most of the Korean adult population continues to follow ether a traditional Korean having beneficial effects for successful aging. However, the 'Traditional Korean' pattern showed low protein intake (0.7 g/kg), calcium intake, and vitamin D intake as well as low of appendicular skeletal muscle mass (ASM (kg)) among 3 groups.

CONCLUSIONS

Considering the low ASM, consumption of protein, calcium and vitamin D should be increased for Korean elderly health body composition.

Sarcopenic obesity in aging population: current status and future directions for research

The combination of sarcopenia and obesity, an age-related change in body composition, is a concern in the aged society. Sarcopenic obesity is not the combination of two conditions, but is more related to cardio-metabolic and functional abnormalities. Sarcopenic obesity is associated with more physical functional decline than simple obesity. Sarcopenic obesity may be more insulin resistant, and have a higher risk for metabolic syndrome and atherosclerosis than simple obesity. However, the prevalence of sarcopenic obesity differs substantially among studies because of the lack of a standard definition. For further understanding of the pathophysiological role of sarcopenic obesity, a standardized definition for both sarcopenia and obesity is necessary.

Muscle changes in aging: understanding sarcopenia

Muscle physiology in the aging athlete is complex. Sarcopenia, the age-related decrease in lean muscle mass, can alter activity level and affect quality of life. This review addresses the microscopic and macroscopic changes in muscle with age, recognizes contributing factors including nutrition and changes in hormone levels, and identifies potential pharmacologic agents in clinical trial that may aid in the battle of this complex, costly, and disabling problem.

LEVEL OF EVIDENCE

Level 5.

Nutrition in chronic pancreatitis

The pancreas is a major player in nutrient digestion. In chronic pancreatitis both exocrine and endocrine insufficiency may develop leading to malnutrition over time. Maldigestion is often a late complication of chronic pancreatic and depends on the severity of the underlying disease. The severity of malnutrition is correlated with two major factors: (1) malabsorption and depletion of nutrients (e.g., alcoholism and pain) causes impaired nutritional status; and (2) increased metabolic activity due to the severity of the disease. Nutritional deficiencies negatively affect outcome if they are not treated. Nutritional assessment and the clinical severity of the disease are important for planning any nutritional intervention. Good nutritional practice includes screening to identify patients at risk, followed by a thoroughly nutritional assessment and nutrition plan for risk patients. Treatment should be multidisciplinary and the mainstay of treatment is abstinence from alcohol, pain treatment, dietary modifications and pancreatic enzyme supplementation. To achieve energy-end protein requirements, oral supplementation might be beneficial. Enteral nutrition may be used when patients do not have sufficient calorie intake as in pylero-duodenal-stenosis, inflammation or prior to surgery and can be necessary if weight loss continues. Parenteral nutrition is very seldom used in patients with chronic pancreatitis and should only be used in case of GI-tract obstruction or as a supplement to enteral nutrition.

Nutritional influences on age-related skeletal muscle loss

Age-related muscle loss impacts on whole-body metabolism and leads to frailty and sarcopenia, which are risk factors for fractures and mortality. Although nutrients are integral to muscle metabolism the relationship between nutrition and muscle loss has only been extensively investigated for protein and amino acids. The objective of the present paper is to describe other aspects of nutrition and their association with skeletal muscle mass. Mechanisms for muscle loss relate to imbalance in protein turnover with a number of anabolic pathways of which the mechanistic TOR pathway and the IGF-1–Akt–FoxO pathways are the most characterised. In terms of catabolism the ubiquitin proteasome system, apoptosis, autophagy, inflammation, oxidation and insulin resistance are among the major mechanisms proposed. The limited research associating vitamin D, alcohol, dietary acid–base load, dietary fat and anti-oxidant nutrients with age-related muscle loss is described. Vitamin D may be protective for muscle loss; a more alkalinogenic diet and diets higher in the anti-oxidant nutrients vitamin C and vitamin E may also prevent muscle loss. Although present recommendations for prevention of sarcopenia focus on protein, and to some extent on vitamin D, other aspects of the diet including fruits and vegetables should be considered. Clearly, more research into other aspects of nutrition and their role in prevention of muscle loss is required.

Sarcopenia: a clinical review

Although sarcopenia has been used to define muscle mass loss in older subjects, muscle mass is not directly linked to muscle function. Recent definitions consider sarcopenia as a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength with a risk of adverse outcomes, such as physical disability, poor quality of life, and death. It is closely linked with physical frailty, and also with other muscle wasting disorders, including cachexia and malnutrition. This review focuses on the incorporation of sarcopenia into clinical practice, reviews case finding and diagnosis of sarcopenia, proposes a syndromic approach for the diagnostic work-up of sarcopenic patients, and looks at intervention trials with physical exercise and nutrition, as drugs to treat this condition are not expected to be available in the near future.