"Diet for the prevention and management of sarcopenia"

Molecular mechanisms and potential interventions during aging-associated sarcopenia

Sarcopenia, a common condition observed in the elderly, presenting a significant public health challenge due to its high prevalence, insidious onset and diverse systemic effects. Despite ongoing research, the precise etiology of sarcopenia remains elusive. Aging-related processes, which included inflammation, oxidative stress, compromised mitochondrial function and apoptosis, have been implicated in its development. Notably, effective pharmacological treatments for sarcopenia are currently lacking, highlighting the necessity for a deeper understanding of its pathogenesis and causative factors to enable proactive interventions. This article is aimed to provide an extensive overview of the pathogenesis of sarcopenia, along with a summary of current treatment and prevention strategies.

Sarcopenia risk in U.S. younger adults: the impact of physical activity intensity and occupational engagement-insights from a cross-sectional NHANES study

OBJECTIVE

This study aimed to investigate the associations between physical activity (PA) intensity, occupational PA engagement, and sarcopenia in younger adults.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) (from 2011 to 2018) were used for the study. PA data were extracted for the Global Physical Activity Questionnaire, and the ratio of limb muscle mass (ALM) to body mass index (BMI) was used to determine sarcopenia. Multiple logistic regression was performed, and dose-response curves were drawn to evaluate the associations.

RESULTS

Of the 8802 adults aged 20 to 59 years, 770 (8.7%) were identified as having sarcopenia. Compared to those in the reference group, the participants in the "low", "moderate", and "high" total METs groups had lower risks of sarcopenia (low: OR = 0.730, 95% CI = 0.583; 0.915; moderate: OR = 0.643, 95% CI = 0.485; 0.853; high: OR = 0.560, 95% CI = 0.457; 0.687). The risk of sarcopenia decreased in the high-intensity recreational PA group; however, such a significant association was observed only in the high-intensity occupational PA group. The relationship between total METs and sarcopenia showed a nonlinear U-shaped trend.

CONCLUSIONS

A greater intensity of PA is associated with a lower risk of sarcopenia among younger adults, regardless of whether moderate or vigorous PA is performed. Moreover, recreational PA may particularly advantageously contrast with occupational PA in lowering the risk of sarcopenia.

Identifying genetic determinants of sarcopenia-related traits: a Mendelian randomization study of druggable genes

BACKGROUND

Sarcopenia, characterized by progressive muscle mass and function loss, particularly affects the elderly, and leads to severe consequences such as falls and mortality. Despite its prevalence, targeted pharmacotherapies for sarcopenia are lacking. Utilizing large-sample genome-wide association studies (GWAS) data is crucial for cost-effective drug discovery.

METHODS

Herein, we conducted four studies to understand the putative causal effects of genetic components on muscle mass and function. Study 1 employed a two-sample Mendelian randomization (MR) on 15,944 potential druggable genes, investigating their potential causality with muscle quantity and quality in a European population (N up to 461,089). Study 2 validated MR results through sensitivity analyses and colocalization analyses. Study 3 extended validation across other European cohorts, and study 4 conducted quantitative in vivo verification.

RESULTS

MR analysis revealed significant causality between four genes (BLOC-1 related complex subunit 7, BORCS7; peptidase m20 domain containing 1, PM20D1; nuclear casein kinase and cyclin dependent kinase substrate 1, NUCKS1 and ubiquinol-cytochrome c reductase complex assembly factor 1, UQCC1) and muscle mass and function (p-values range 5.98 × 10-6 to 9.26 × 10-55). To be specific, BORCS7 and UQCC1 negatively regulated muscle quantity and quality, whereas enhancing PM20D1 and NUCKS1 expression showed promise in promoting muscle mass and function. Causal relationships remained robust across sensitivity analyses, with UQCC1 exhibiting notable colocalization effects (PP·H4 93.4 % to 95.8 %). Further validation and in vivo replication verified the potential causality between these genes and muscle mass as well as function.

CONCLUSIONS

Our druggable genome-wide MR analysis identifies BORCS7, PM20D1, NUCKS1, and UQCC1 as causally associated with muscle mass and function. These findings offer insights into the genetic basis of sarcopenia, paving the way for these genes to become promising drug targets in mitigating this debilitating condition.

Adipose tissue in older individuals: a contributing factor to sarcopenia

Sarcopenia is a geriatric syndrome characterized by a functional decline in muscle. The prevalence of sarcopenia increases with natural aging, becoming a serious health problem among elderly individuals. Therefore, understanding the pathology of sarcopenia is critical for inhibiting age-related alterations and promoting health and longevity in elderly individuals. The development of sarcopenia may be influenced by interactions between visceral and subcutaneous adipose tissue and skeletal muscle, particularly under conditions of chronic low-grade inflammation and metabolic dysfunction. This hypothesis is supported by the following observations: (i) accumulation of senescent cells in both adipose tissue and skeletal muscle with age; (ii) gut dysbiosis, characterized by an imbalance in gut microbial communities as the main trigger for inflammation, sarcopenia, and aged adipose tissue; and (iii) microbial dysbiosis, which could impact the onset or progression of a senescent state. Moreover, adipose tissue acts as an endocrine organ, releasing molecules that participate in intricate communication networks between organs. Our discussion focuses on novel adipokines and their role in regulating adipose tissue and muscle, particularly those influenced by aging and obesity, emphasizing their contributions to disease development. On the basis of these findings, we propose that age-related adipose tissue and sarcopenia are disorders characterized by chronic inflammation and metabolic dysregulation. Finally, we explore new potential therapeutic strategies involving specialized proresolving mediator (SPM) G protein-coupled receptor (GPCR) agonists, non-SPM GPCR agonists, transient receptor potential (TRP) channels, antidiabetic drugs in conjunction with probiotics and prebiotics, and compounds designed to target senescent cells and mitigate their pro-inflammatory activity.

[Thickness of the rectus femorius muscle and vastus intermedium muscle in older Mexican adults with frailty and sarcopenia]

BACKGROUND AND OBJECTIVE

Frailty in older adults is a geriatric syndrome that has gained importance in the last decade. However, there is still no consolidated information regarding diagnostic tools that allow timely identification, and therefore, provide an appropriate therapeutic approach. The objective is to determine the Thickness of the Rectus Femoris Muscle (GMRF) and Thickness of the Vastus Intermedius Muscle (GMVI) in older Mexican adults with frailty and sarcopenia.

MATERIAL AND METHODS

Cross-sectional, descriptive and comparative study in patients ≥65 years of age, admitted to the geriatrics service. The selection was according to the FRAIL (frail vs. non-frail) and SARC-F (high risk vs. low risk) classification; evaluating GMRF and GMVI by ultrasound. The data were analyzed through the statistical software Statistical Package for Social Sciences (SPSS) ver. 25.

RESULTS

The number of patients evaluated in the study and control group were 136 respectively. Significant differences were found regarding frailty status in age (years) (Frail: 75.06±7.92 vs. Non-frail: 71.60±5.56; P<.001), GMRF (mm) (Frail: 8.41±3.08 vs. Non-frail: 11.03±3.50; P<.001) and GMVI (mm) (Frail: 6.53±2.64 vs. Non-frail: 8.66±2.68; P<.001); Considering sarcopenia, there were differences in age (years) (High risk sarcopenia: 75.17±7.84: vs low risk sarcopenia; 71.49±5.60; P<.001), GMRF (mm) (high risk sarcopenia: 8.45±3.11 vs low risk sarcopenia: 10.98±3.50; P<.001) and GMVI (mm) (High risk Sarcopenia: 6.67±2.63 vs Low risk Sarcopenia: 8.52±2.79; P<.001).

CONCLUSIONS

The results found show that there is a significant difference in GMRF and GMVI in Mexican older adults with respect to frailty and sarcopenia. In this way, the present investigation establishes clinical bases for the use of ultrasonography assessments in the geriatric population.

Emerging Targets and Treatments for Sarcopenia: A Narrative Review

BACKGROUND

Sarcopenia is characterized by the progressive loss of skeletal muscle mass, strength, and function, significantly impacting overall health and quality of life in older adults. This narrative review explores emerging targets and potential treatments for sarcopenia, aiming to provide a comprehensive overview of current and prospective interventions.

METHODS

The review synthesizes current literature on sarcopenia treatment, focusing on recent advancements in muscle regeneration, mitochondrial function, nutritional strategies, and the muscle-microbiome axis. Additionally, pharmacological and lifestyle interventions targeting anabolic resistance and neuromuscular junction integrity are discussed.

RESULTS

Resistance training and adequate protein intake remain the cornerstone of sarcopenia management. Emerging strategies include targeting muscle regeneration through myosatellite cell activation, signaling pathways, and chronic inflammation control. Gene editing, stem cell therapy, and microRNA modulation show promise in enhancing muscle repair. Addressing mitochondrial dysfunction through interventions aimed at improving biogenesis, ATP production, and reducing oxidative stress is also highlighted. Nutritional strategies such as leucine supplementation and anti-inflammatory nutrients, along with dietary modifications and probiotics targeting the muscle-microbiome interplay, are discussed as potential treatment options. Hydration and muscle-water balance are emphasized as critical in maintaining muscle health in older adults.

CONCLUSIONS

A combination of resistance training, nutrition, and emerging therapeutic interventions holds potential to significantly improve muscle function and overall health in the aging population. This review provides a detailed exploration of both established and novel approaches for the prevention and management of sarcopenia, highlighting the need for further research to optimize these strategies.

Dietary vitamin K intake in relation to skeletal muscle mass and strength among adults: a cross-sectional study based on NHANES

Background

Previous studies revealed that vitamin K might help maintain muscle homeostasis, but this association has received little attention. We aimed to explore the associations of vitamin K intake with skeletal muscle mass and strength.

Methods

We included cross-sectional data from the U.S. National Health and Nutrition Examination Survey (NHANES, 2011-2018). Vitamin K intake was assessed via 24-h recall. Covariate-adjusted multiple linear regression and restricted cubic splines were used to evaluate the associations of dietary vitamin K intake with skeletal muscle mass and strength, measured by dual-energy X-ray absorptiometry and handgrip dynamometer, respectively.

Results

Dietary vitamin K intake was positively associated with skeletal muscle mass in males (β = 0.05747, p = 0.0204) but not in females. We also revealed a positive association between dietary vitamin K intake and handgrip strength within the range of 0-59.871 μg/d (P nonlinear = 0.049). However, beyond this threshold, increasing vitamin K intake did not cause additional handgrip strength improvements.

Conclusion

We provided evidence for a positive relationship between dietary vitamin K intake and skeletal muscle mass in males. Moreover, our study revealed a nonlinear relationship between dietary vitamin K intake and handgrip strength, highlighting an optimal intake range.

Unmodulated 40 Hz Stimulation as a Therapeutic Strategy for Aging: Improvements in Metabolism, Frailty, and Cognitive Function in Senescence-Accelerated Prone 10 Mice

With aging populations in many countries, including Japan, efforts to mitigate the aging-related decline in physical function have gained importance not only for improving individual quality of life but also for mitigating the effects of this loss of function on society. Impaired glucose tolerance, muscle weakness, and cognitive decline are well-known effects of aging. These interrelated factors can create a vicious cycle because impaired glucose tolerance can accelerate muscle weakness and cognitive decline. Unmodulated 40 Hz (u40Hz) stimulation is imperceptible to the human ear and has been reported to improve cognitive function in humans and mice. However, research on the effects of u40Hz stimulation is still limited. This study aimed to report the effects of u40Hz stimulation on glucose tolerance and muscle strength in senescence-accelerated prone (SAMP)-10 mice, a model of accelerated aging. SAMP-10 mice underwent five weeks of u40Hz stimulation followed by glucose-tolerance tests, cognitive and behavioral assessments, and frailty evaluations. In comparison with the control group, the u40Hz-stimulation group showed mitigation of age-related decline in glucose tolerance, a better frailty index (FI), and notably preserved muscle strength. Microarray analysis of stimulated muscle tissue revealed significant upregulation of β-oxidation genes and genes functioning downstream of peroxisome proliferator-activated receptor gamma, and significant downregulation of clock genes. These findings indicate the beneficial effects of u40Hz stimulation on glucose tolerance, muscle strength, and cognitive function, warranting further research in this area.

Diagnosis of Sarcopenia and Myosteatosis by Computed Tomography in Patients with Esophagogastric and Pancreatic Cancer

The increase in the global incidence of cancer highlights the need to continue advancing in the techniques of diagnosis and nutritional assessment of cancer patients, given the prognostic and therapeutic impact of nutritional status. In this study, sarcopenia was evaluated as an independent predictor of morbidity and mortality. Data from 45 patients diagnosed with esophagogastric or pancreatic cancer were analyzed. Body composition was determined using computed tomography images, and functionality tests were performed. Sarcopenia was present in 22.2% of the patients, while only 31.1% had correct musculature. A reduction in muscle mass or function was observed in 46.7% of the patients. Likewise, the prevalence of myosteatosis reached 60% of the patients. No significant differences were found with regard to the presence of sarcopenia according to BMI classifications, so it is necessary to evaluate the patient with body composition techniques that include the evaluation of the different muscle and fat compartments. In conclusion, a comprehensive intervention is necessary to improve the detection of sarcopenia/myosteatosis and, in the future, to be able to carry out an approach that improves the quality of life and survival rates of patients.

The associations of adherence to the Mediterranean diet with chronic dizziness and imbalance in community-dwelling adults: KNHANES 2019-2021

BACKGROUND

Dizziness and vertigo rank among the top 10 reasons for emergency and clinical referrals to neurologists. Chronic dizziness and imbalance not only reduce quality of life, but also increase mortality. While the Mediterranean diet has long been considered beneficial for human and planetary health, its effects on chronic dizziness or imbalance are understudied. We investigated the associations of adherence to the Mediterranean diet with chronic dizziness and imbalance.

METHODS

This study used data from the Korea National Health and Nutrition Examination Survey 2019-2021 and included 4,183 adults aged 40 years and older with complete information from diet, dizziness, and neurotology questionnaires. The alternate Mediterranean diet score (aMed) for nine food groups was calculated from 24-hour dietary recall data. Based on questionnaire responses, chronic dizziness was categorized as either isolated or chronic dizziness with imbalance, characterized by a cluster of difficulties maintaining a standing position, walking, or falling.

RESULTS

In a multivariable-adjusted model, the prevalence of chronic imbalance was lower in the top aMed tertile than in the bottom tertile (OR 0.37; 95% CI, 0.18-0.74; p-trend = 0.01). Among the individual aMed components, the intake of whole grains and nuts exhibited an inverse relationship with chronic imbalance (OR 0.50; 95% CI, 0.27-0.93 for whole grains; OR 0.55; 95% CI, 0.31-1.01 for nuts). The aMed score was not associated with isolated chronic dizziness.

CONCLUSIONS

Greater adherence to the Mediterranean diet may reduce chronic imbalance, particularly with an adequate intake of whole grains and nuts.

Steatotic Liver Disease: Pathophysiology and Emerging Pharmacotherapies

Steatotic liver disease (SLD) displays a dynamic and complex disease phenotype. Consequently, the metabolic dysfunction-associated steatotic liver disease (MASLD)/metabolic dysfunction-associated steatohepatitis (MASH) therapeutic pipeline is expanding rapidly and in multiple directions. In parallel, noninvasive tools for diagnosing and monitoring responses to therapeutic interventions are being studied, and clinically feasible findings are being explored as primary outcomes in interventional trials. The realization that distinct subgroups exist under the umbrella of SLD should guide more precise and personalized treatment recommendations and facilitate advancements in pharmacotherapeutics. This review summarizes recent updates of pathophysiology-based nomenclature and outlines both effective pharmacotherapeutics and those in the pipeline for MASLD/MASH, detailing their mode of action and the current status of phase 2 and 3 clinical trials. Of the extensive arsenal of pharmacotherapeutics in the MASLD/MASH pipeline, several have been rejected, whereas other, mainly monotherapy options, have shown only marginal benefits and are now being tested as part of combination therapies, yet others are still in development as monotherapies. Although the Food and Drug Administration (FDA) has recently approved resmetirom, additional therapeutic approaches in development will ideally target MASH and fibrosis while improving cardiometabolic risk factors. Due to the urgent need for the development of novel therapeutic strategies and the potential availability of safety and tolerability data, repurposing existing and approved drugs is an appealing option. Finally, it is essential to highlight that SLD and, by extension, MASLD should be recognized and approached as a systemic disease affecting multiple organs, with the vigorous implementation of interdisciplinary and coordinated action plans. SIGNIFICANCE STATEMENT: Steatotic liver disease (SLD), including metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis, is the most prevalent chronic liver condition, affecting more than one-fourth of the global population. This review aims to provide the most recent information regarding SLD pathophysiology, diagnosis, and management according to the latest advancements in the guidelines and clinical trials. Collectively, it is hoped that the information provided furthers the understanding of the current state of SLD with direct clinical implications and stimulates research initiatives.

Myoprotective whole foods, muscle health and sarcopenia in older adults

PURPOSE OF REVIEW

Sarcopenia increases in prevalence at older ages and may be exacerbated by poor diet. Whole foods rich in specific nutrients may be myoprotective and mitigate the risk of sarcopenia. Here we review recent evidence published from observational and intervention studies regarding myoprotective foods and explore their benefit for the prevention and/or treatment of sarcopenia in older adults.

RECENT FINDINGS

We found limited new evidence for the role of whole foods in sarcopenia and sarcopenia components (muscle mass, strength, physical performance). There was some evidence for higher consumption of protein-rich foods (milk and dairy) being beneficial for muscle strength in observational and intervention studies. Higher consumption of antioxidant-rich foods (fruit and vegetables) was associated with better physical performance and lower odds of sarcopenia in observational studies. Evidence for other protein- and antioxidant-rich foods were inconsistent or lacking. There remains a clear need for intervention studies designed to identify the role of whole foods for the treatment of sarcopenia.

SUMMARY

Although evidence for myoprotective roles of dairy, fruit and vegetables is emerging from observational studies, higher level evidence from intervention studies is needed for these foods to be recommended in diets of older adults to prevent and/or treat sarcopenia.

Joint trajectories of loneliness, social isolation and sarcopenia and associations with adverse outcomes: A prospective cohort study

This study aimed to examine joint trajectories of loneliness, social isolation and sarcopenia and their associations with adverse outcomes. A total of 4701 participants aged ≥60 years who had a baseline and at least one follow-up assessment of loneliness, social isolation and sarcopenia across 2011, 2013 and 2015 waves in China Health and Retirement Longitudinal Study. Adverse outcomes were obtained in 2018 wave. Joint trajectories were fit using the parallel process latent class growth analysis, and their associations with adverse outcomes were evaluated using modified Poisson regression. Joint trajectory patterns for social relationship and sarcopenia did not vary by the assessment for sarcopenia, but did vary by the assessment for social relationship. Older adults exhibit distinct joint trajectories and those with persistent combination of loneliness or social isolation and sarcopenia experience greatest risk of adverse outcomes. These findings implicate integration of health care and social care for community-dwelling older adults.

Comparative Efficacy of Different Protein Supplements on Muscle Mass, Strength, and Physical Indices of Sarcopenia among Community-Dwelling, Hospitalized or Institutionalized Older Adults Undergoing Resistance Training: A Network Meta-Analysis of Randomized Controlled Trials

Aging-related sarcopenia exerts harmful impacts on muscle mass, strength, and physical mobility. Protein supplementation has been demonstrated to augment efficacy of resistance training (RT) in elderly. This study compared the relative effects of different protein supplements on muscle mass, strength, and mobility outcomes in middle-aged and older individuals undergoing RT. A comprehensive search of online databases was performed to identify randomized controlled trials (RCTs) examining the efficacy of protein supplement plus RT in untrained community-dwelling adults, hospitalized, or institutionalized residents who suffered acute or chronic health conditions. Network meta-analysis (NMA) was performed using a frequentist method for all analyses. Treatment effects for main outcomes were expressed as standard mean difference (SMD) with 95% confidence interval (CI). We used the surface-under-the cumulative-ranking (SUCRA) scores to rank probabilities of effect estimation among all identified treatments. Meta-regression analyses were performed to identify any relevant moderator of the treatment efficacy and results were expressed as β with 95% credible interval (CrI). We finally included 78 RCTs (5272 participants) for analyses. Among the six protein sources identified in this NMA, namely whey, milk, casein, meat, soy, and peanut, whey supplement yielded the most effective treatments augmenting efficacy of RT on muscle mass (SMD = 1.29, 95% CI: 0.96, 1.62; SUCRA = 0.86), handgrip strength (SMD = 1.46, 95% CI: 0.92, 2.00; SUCRA = 0.85), and walking speed (SMD = 0.73, 95% CI: 0.39, 1.07; SUCRA = 0.84). Participant's health condition, sex, and supplementation dose were significant factors moderating the treatment efficacy on muscle mass (β = 0.74; 95% CrI: 0.22, 1.25), handgrip strength (β = -1.72; 95% CrI: -2.68, -0.77), and leg strength (β = 0.76; 95% CrI: 0.06, 1.47), respectively. Our findings suggest whey protein yields the optimal supplements to counter sarcopenia in older individuals undergoing RT.

Sarcopenia and Neuroendocrine Neoplasms

PURPOSE OF THE REVIEW

To summarise the current literature regarding the presence of sarcopenia in patients with neuroendocrine neoplasms (NENs). These are uncommon cancers separated into well-differentiated neuroendocrine tumours (NETs) and poorly differentiated neuroendocrine carcinoma (NECs). For the diagnosis of sarcopenia, there needs to be low muscle strength and low muscle quantity/quality.

RECENT FINDINGS

Five studies exist describing either low muscle strength or low muscle quantity in patients with NETs. The studies used different techniques to analyse muscle strength and muscle quantity, included heterogeneous populations, and performed the analysis at different time points following the diagnosis of the NET. Only 2 studies regarding patients with NECs could be found, both included mainly patients with a mixed adenoneuroendocrine carcinoma (MiNEN) and are, therefore, difficult to interpret for patients with a NEC. The main findings of this review are to describe the presence of sarcopenia in patients with NENs. However, results should be interpreted with caution, and future research should focus on the correct technique, homogenous population and same time point.

Lower Adherence to a Mediterranean Diet Is Associated with High Adiposity in Community-Dwelling Older Adults: Results from the Longevity Check-Up (Lookup) 7+ Project

High adiposity impacts health and quality of life in old age, owing to its association with multimorbidity, decreased physical performance, and frailty. Whether a high adherence to a Mediterranean diet (Medi-Diet) is associated with reduced body adiposity in older adults is unclear. The present study was conducted to assess the prevalence of high adiposity in a large sample of community-dwelling older adults. We also explored the relationship between whole-body adiposity estimated through relative fat mass (RFM) and Medi-Diet adherence. Data were obtained from the Longevity Check-up 7+ (Lookup7+) project database. RFM was estimated from anthropometric and personal parameters using a validated equation. RFM was categorized as high if ≥40% in women and ≥30% in men. Information on diet was collected using a food frequency questionnaire, while Medi-Diet adherence was assessed through a modified version of the Medi-Lite scoring system. Analyses were conducted in 2092 participants (mean age 73.1 ± 5.9 years; 53.4% women). Mean RFM was 39.6 ± 5.14% in women and 29.0 ± 3.6% in men. High adiposity was found in 971 (46.4%) participants and was more frequent in those with a low (54.2%) or moderate (46.4%) Medi-Diet adherence compared with the high-adherence group (39.7%, p < 0.001). Logistic regression indicated that older adults with high Medi-Diet adherence were less likely to have a high RFM. Other factors associated with a greater risk of having high adiposity were older age, female sex, and physical inactivity. Our findings support an association between healthy lifestyles, including a greater adherence to a Mediterranean-style diet, and lower body adiposity in older adults.

The association of living alone and social isolation with sarcopenia: A systematic review and meta-analysis

BACKGROUND

Living alone can cause social isolation and is correlated with multiple adverse health outcomes. Evidence about the association of living alone and social isolation with sarcopenia is limited. This meta-analysis aims to investigate the correlation between living alone, social isolation, and sarcopenia.

METHODS

According to the PRISMA guidelines, we systematically searched Medline, Embase, Web of Science, and Scopus for literature published up to June 30, 2023. We conducted reference checking to supplement the references. Two investigators independently screened the references for eligibility and assessed the quality of the references. We included references involving data on living alone, social isolation, and sarcopenia. Two investigators recorded study data for meta-analysis and study characteristics.

RESULTS

Data regarding living alone and sarcopenia were available from 13 studies. Meta-analysis demonstrated that living alone is correlated with sarcopenia (odds ratio, 1.51; 95 % CI, 1.31-1.75; p < 0.001). The gender-stratified analysis demonstrated that women living alone are more likely to have sarcopenia (odds ratio, 1.81; 95 % CI, 1.32-2.48; p < 0.001) but not men (odds ratio, 1.24; 95 % CI, 0.56-2.74; p = 0.60). Data regarding social isolation and sarcopenia were available from five studies. Social isolation is also associated with sarcopenia (odds ratio, 1.70; 95 % CI, 1.51-1.92; p < 0.001). And subgroup analysis demonstrated that social isolation is a risk factor for sarcopenia (odds ratio, 1.79; 95 % CI, 1.55-2.06; p < 0.001).

CONCLUSIONS

This meta-analysis revealed the association of living alone and social isolation with sarcopenia. Gender differences can help to screen high-risk groups of sarcopenia and reduce healthcare expenditures. As a further development of living alone, social isolation may play a more important role in sarcopenia than living alone.

Effects of Omega-3 Fatty Acid Supplementation on Skeletal Muscle Mass and Strength in Adults: A Systematic Review

Previous studies have suggested that omega-3 polyunsaturated fatty acids, predominantly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have several health benefits. However, their effect on changes in skeletal muscle mass and strength has not been established, owing to differences in study designs. This systematic review aimed to investigate the recent evidence regarding the role of dietary EPA and DHA in muscle mass changes and their association with muscle strength. Databases including PubMed and Google Scholar were searched for randomized controlled trials and single-arm interventions that investigated the effects of omega-3 fatty acids on skeletal muscle mass, strength, and body composition in adults aged 18 years and older. A total of 18,521 studies were retrieved from the databases and manual searches; 21 studies were quality assessed, and the findings were summarized. Studies were categorized into 3 main categories according to the type of omega-3 fatty acid supplementation: pure compounds such as oil tablets, formulated forms with protein, leucine, and vitamin D, and ingredients added to enteral nutrition support products. Overall, the majority of the study results appeared to indicate that omega-3 fatty acids are beneficial for muscle health. However, meta-analysis was not conducted because of the heterogeneity of the study participants, evaluation method of muscle indices, and intervention periods among the studies. High-quality studies are required to validate our conclusions. However, this systematic review of the effects of EPA and DHA on skeletal muscle and body composition provides evidence that can be applied in both clinical and industrial settings.

The Role of Nutrition in the Treatment of Sarcopenia in Old Patients: From Restoration of Mitochondrial Activity to Improvement of Muscle Performance, a Systematic Review

Sarcopenia is an age-related disease characterized by loss of muscle strength, mass and performance. Malnutrition contributes to sarcopenia pathogenesis. The aim of this systematic review is to analyze existing evidence on the efficacy of nutritional supplementation on muscle and mitochondrial health among sarcopenic or malnourished older adults. We included randomized controlled trials (RCTs) assessing the effect of branched-chain amino acid (BCAA), vitamin D and/or omega-3 polyunsaturated fatty acid (PUFA) on muscle mass, strength and performance and/or on mitochondrial activity and redox state in older sarcopenic and/or malnourished adults. The literature search was on MEDLINE, Embase and Cochrane Central, restricted to articles published in the last 10 years (2012-2022). Twelve RCTs with a total of 1337 subjects were included. BCAA with vitamin D significantly ameliorates appendicular muscle mass (4 RCTs), hand grip strength (4 RCTs), gait speed (3 RCTs), short physical performance battery (3 RCTs) or chair stand test (3 RCTs) among six out of nine RCTs. BCAA alone (2 RCTs) or PUFA (1 RCT) were not effective in improving muscle health. Mitochondrial function was significantly improved by the administration of BCAA alone (1 RCT) or in association with vitamin D (1 RCT). In conclusion, BCAA in association with vitamin D may be useful in the treatment of sarcopenia and boost mitochondrial bioenergetic and redox activity. PROSPERO CRD42022332288.

Combined Aerobic Training and Mediterranean Diet Is Not Associated with a Lower Prevalence of Sarcopenia in Italian Older Adults

Previous studies found a lower prevalence of sarcopenia in older adults engaged in regular aerobic training (AT) or with greater adherence to a Mediterranean (MED) diet. However, the effect of their combination on sarcopenia indices is unknown. The present study tested the association between AT plus a MED diet and the presence of sarcopenia and its defining elements in a sample of Italian older adults enrolled in the Longevity Check-up 7+ (Lookup 7+) project. Analyses were conducted in participants 65+ years, with a body mass index of at least 18.5 kg/m2, engaged in regular AT, and without missing information for the variables of interest. MED diet adherence was evaluated via a modified version of the MEDI-LITE score and categorized as low, moderate, or high. The presence of sarcopenia was established by handgrip strength and appendicular skeletal muscle mass (ASM) values below sex-specific cut-points recommended by the European Working Group on Sarcopenia in Older People 2. Data from 491 older adults were analyzed for the present study. The mean age was 72.7 ± 5.7 years, and 185 (37.7%) were women. MED diet adherence was low in 59 (12.0%) participants, moderate in 283 (57.6%), and high in 149 (30.3%). Sarcopenia was identified in 26 participants (5.3%), with no differences across MED diet adherence groups. The results of binary logistic regression showed no significant associations between AT plus adherence to a MED diet and dynapenia, low ASM, or sarcopenia. The findings of the present study indicate that the combination of AT with a MED diet is not associated with a lower probability of sarcopenia or its defining elements in Italian older adults enrolled in Lookup 7+. Further research is warranted to establish whether exercise frequency, volume, intensity, and length of engagement in AT impact the association between MED diet and sarcopenia.