Fish oil-derived n-3 polyunsaturated fatty acids for the prevention and treatment of sarcopenia

Skeletal muscle dysfunction with advancing age

As a result of advances in medical treatments and associated policy over the last century, life expectancy has risen substantially and continues to increase globally. However, the disconnect between lifespan and 'health span' (the length of time spent in a healthy, disease-free state) has also increased, with skeletal muscle being a substantial contributor to this. Biological ageing is accompanied by declines in both skeletal muscle mass and function, termed sarcopenia. The mechanisms underpinning sarcopenia are multifactorial and are known to include marked alterations in muscle protein turnover and adaptations to the neural input to muscle. However, to date, the relative contribution of each factor remains largely unexplored. Specifically, muscle protein synthetic responses to key anabolic stimuli are blunted with advancing age, whilst alterations to neural components, spanning from the motor cortex and motoneuron excitability to the neuromuscular junction, may explain the greater magnitude of function losses when compared with mass. The consequences of these losses can be devastating for individuals, their support networks, and healthcare services; with clear detrimental impacts on both clinical (e.g., mortality, frailty, and post-treatment complications) and societal (e.g., independence maintenance) outcomes. Whether declines in muscle quantity and quality are an inevitable component of ageing remains to be completely understood. Nevertheless, strategies to mitigate these declines are of vital importance to improve the health span of older adults. This review aims to provide an overview of the declines in skeletal muscle mass and function with advancing age, describes the wide-ranging implications of these declines, and finally suggests strategies to mitigate them, including the merits of emerging pharmaceutical agents.

Non-Pharmacological Strategies for Managing Sarcopenia in Chronic Diseases

This article focuses on a range of non-pharmacological strategies for managing sarcopenia in chronic diseases, including exercise, dietary supplements, traditional Chinese exercise, intestinal microecology, and rehabilitation therapies for individuals with limited limb movement. By analyzing multiple studies, the article aims to summarize the available evidence to manage sarcopenia in individuals with chronic diseases. The results strongly emphasize the role of resistance training in addressing chronic diseases and secondary sarcopenia. Maintaining the appropriate frequency and intensity of resistance training can help prevent muscle atrophy and effectively reduce inflammation. Although aerobic exercise has limited ability to improve skeletal muscle mass, it does have some positive effects on physical function. Building upon this, the article explores the potential benefits of combined training approaches, highlighting their helpfulness for overall quality of life. Additionally, the article also highlights the importance of dietary supplements in combating muscle atrophy in chronic diseases. It focuses on the importance of protein intake, supplements rich in essential amino acids and omega-3, as well as sufficient vitamin D to prevent muscle atrophy. Combining exercise with dietary supplements appears to be an effective strategy for preventing sarcopenia, although the optimal dosage and type of supplement remain unclear. Furthermore, the article explores the potential benefits of intestinal microecology in sarcopenia. Probiotics, prebiotics, and bacterial products are suggested as new treatment options for sarcopenia. Additionally, emerging therapies such as whole body vibration training, blood flow restriction, and electrical stimulation show promise in treating sarcopenia with limited limb movement. Overall, this article provides valuable insights into non-pharmacological strategies for managing sarcopenia in individuals with chronic diseases. It emphasizes the importance of a holistic and integrated approach that incorporates exercise, nutrition, and multidisciplinary interventions, which have the potential to promote health in the elderly population. Future research should prioritize high-quality randomized controlled trials and utilize wearable devices, smartphone applications, and other advanced surveillance methods to investigate the most effective intervention strategies for sarcopenia associated with different chronic diseases.

The nutritional support to prevent sarcopenia in the elderly

Sarcopenia has been described as a muscle disease, with multiple adverse consequences on human health. Recommendations aimed at supporting awareness, prevention, early detection and treatment of this disease are needed. This review focuses on the epidemiology, pathophysiology and early detection of elderly sarcopenia. As far as treatment is concerned, physical activity and nutritional support are specifically evaluated. An individually tailored resistance exercise training program appears to be crucial for a positive outcome of the sarcopenia prevention and treatment. The nutritional intervention is mostly based on the supplementation with high-quality proteins (i.e., whey protein) in order to increase the intake of essential amino acids and in particular of leucine. In addition, of relevant importance appears to be the supplementation with vitamin D, with omega-3 fatty acids and probiotics. This review evaluates the results of the most qualified studies on the nutritional supplementation of sarcopenic elderly subjects and shows that promising results have been achieved in community elderly subjects, or subjects followed in rehabilitation centers and in nursing homes, with additional resistance exercise programs.

Restoration of epigenetic impairment in the skeletal muscle and chronic inflammation resolution as a therapeutic approach in sarcopenia

Sarcopenia is an age-associated loss of skeletal muscle mass, strength, and function, accompanied by severe adverse health outcomes, such as falls and fractures, functional decline, high health costs, and mortality. Hence, its prevention and treatment have become increasingly urgent. However, despite the wide prevalence and extensive research on sarcopenia, no FDA-approved disease-modifying drugs exist. This is probably due to a poor understanding of the mechanisms underlying its pathophysiology. Recent evidence demonstrate that sarcopenia development is characterized by two key elements: (i) epigenetic dysregulation of multiple molecular pathways associated with sarcopenia pathogenesis, such as protein remodeling, insulin resistance, mitochondria impairments, and (ii) the creation of a systemic, chronic, low-grade inflammation (SCLGI). In this review, we focus on the epigenetic regulators that have been implicated in skeletal muscle deterioration, their individual roles, and possible crosstalk. We also discuss epidrugs, which are the pharmaceuticals with the potential to restore the epigenetic mechanisms deregulated in sarcopenia. In addition, we discuss the mechanisms underlying failed SCLGI resolution in sarcopenia and the potential application of pro-resolving molecules, comprising specialized pro-resolving mediators (SPMs) and their stable mimetics and receptor agonists. These compounds, as well as epidrugs, reveal beneficial effects in preclinical studies related to sarcopenia. Based on these encouraging observations, we propose the combination of epidrugs with SCLI-resolving agents as a new therapeutic approach for sarcopenia that can effectively attenuate of its manifestations.

Long-chain n -3 polyunsaturated fatty acids for the management of age- and disease-related declines in skeletal muscle mass, strength and physical function

PURPOSE OF REVIEW

This review uses the hierarchy of evidence as a framework to critically evaluate the effect of long chain n -3 polyunsaturated fatty acid (LC n -3 PUFA) ingestion alone, or as an adjunctive intervention to resistance training, on muscle health-related outcomes in healthy and clinical older adult populations.

RECENT FINDINGS

Systematic reviews and meta-analyses of randomized controlled trials consistently report small, but clinically-relevant, effects of LC n -3 PUFA ingestion on strength outcomes, whereas mixed findings have been reported regarding changes in muscle mass and physical function. Cohort studies indicate an association between higher dietary LC n -3 PUFA intake and reduced likelihood of a sarcopenia diagnosis. Acute metabolic studies provide limited evidence for an effect of LC n -3 PUFA ingestion alone, or in combination with resistance training, on free-living integrated rates of MPS, static markers of muscle protein breakdown, or satellite cell activation in healthy older adults.

SUMMARY

Recent data supports the efficacy of LCn-3 PUFA ingestion to facilitate small, but clinically relevant, improvements in muscle strength in healthy and clinical older adult populations. The mechanism(s) that underpin the action of LC n -3 PUFA in promoting strength outcomes remain unknown, but likely relate to neuromuscular function.

Omega-3 polyunsaturated fatty acids in sarcopenia management: A network meta-analysis of randomized controlled trials

Sarcopenia frequently occurs with aging and leads to major adverse impacts on activities of daily living and quality of life in elderly individuals. Omega-3 polyunsaturated fatty acid (omega-3 PUFAs) supplements are considered promising therapeutic agents for sarcopenia management; however, the evidence remains inconsistent. We reviewed randomized controlled trials (RCTs) about omega-3 PUFA supplementation in patients with sarcopenia or in those at high risk for sarcopenia. Network meta-analysis (NMA) procedures were conducted using a frequentist model. The primary outcomes were (1) upper-extremity muscle strength and (2) lower-extremity physical function. The NMA of 16 RCTs showed that the high-dose (more than 2.5 g/day omega-3 PUFAs) group yielded the greatest improvement in both upper-extremity muscle strength and lower-extremity physical function [compared to placebo/standard care groups, standardized mean difference (SMD)= 1.68, 95% confidence interval (95%CI)= 0.03-3.33, and SMD= 0.73, 95%CI= 0.16-1.30, respectively], and the effects were reaffirmed in subgroup analyses of placebo-controlled RCTs or those excluding concurrent resistance training programs. None of the investigated omega-3 PUFAs supplementation was associated with significantly increased skeletal muscle mass, fat mass, or overall body weight. Our findings provide a basis for future large-scale RCTs to investigate the dose effects and clinical application of omega-3 PUFA supplementation in sarcopenia management. TRIAL REGISTRATION: The current study was approved by the Institutional Review Board of the Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (TSGHIRB No. B-109-29) and registered in PROSPERO (CRD42022347161).

A narrative review on the impact of sarcopenic obesity and its psychological consequence in quality of life

BACKGROUND AND AIM

Sarcopenia is a multifactorial metabolic-mediated complication that affects most of the geriatric population physically and mentally. In this study, we intended to study the association between sarcopenia and psychologically related symptoms. Primary objective of the study is to explore the interplay between sarcopenic obesity, psychological consequences and Quality of life in the affected population. The secondary objective is to discuss the diagnostic, treatment approaches and also the role of clinical pharmacist.

METHOD

The psychology-related complication and sarcopenia association was enumerated in this study based on previous clinical research findings.

RESULT

The clinical evidence shows a strong correlation between sarcopenia and Mental health and its health consequences and reflection on the quality of life.

CONCLUSION

Sarcopenia induced mental disturbance has been affirmed in many studies. We believe effective right pharmacological therapy and non-pharmacological therapies with respective lifestyle modification advice could be potential vital factors that can reduce further complications in geriatric populations.

The Effect of Long Chain n-3 Fatty Acid Supplementation on Muscle Strength in Older Adults: A Systematic Review and Meta-Analysis

The main objective of the current study was to perform a systematic literature review with the purpose of exploring the impact of long-chain n-3 polyunsaturated fatty acid (LCn-3 PUFA) relative to control oil supplementation on muscle strength, with secondary outcomes of muscle mass and physical function in older individuals under conditions of habitual physical activity/exercise. The review protocol was registered with PROSPERO (CRD42021267011) and followed the guidelines outlined in the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The search for relevant studies was performed utilizing databases such as PubMed, EMBASE, CINAHL, Scopus, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL) up to June 2023. Randomized controlled trials (RCTs) in older adults comparing the effects of LCn-3 PUFA with a control oil supplement on muscle strength were included. Five studies involving a total of 488 participants (348 females and 140 males) were identified that met the specified inclusion criteria and were included. Upon analyzing the collective data from these studies, it was observed that supplementation with LCn-3 PUFA did not have a significant impact on grip strength (standardized mean difference (SMD) 0.61, 95% confidence interval [-0.05, 1.27]; p = 0.07) in comparison to the control group. However, there was a considerable level of heterogeneity among the studies (I2 = 90%; p < 0.001). As secondary outcomes were only measured in a few studies, with significant heterogeneity in methods, meta-analyses of muscle mass and functional abilities were not performed. Papers with measures of knee extensor muscle mass as an outcome (n = 3) found increases with LCn-3 PUFA supplementation, but studies measuring whole body lean/muscle mass (n = 2) and functional abilities (n = 4) reported mixed results. With a limited number of studies, our data indicate that LCn-3 PUFA supplementation has no effect on muscle strength or functional abilities in older adults but may increase muscle mass, although, with only a few studies and considerable heterogeneity, further work is needed to confirm these findings.

The Effect of Omega-3 Fatty Acids on Sarcopenia: Mechanism of Action and Potential Efficacy

Sarcopenia, a progressive disease characterized by a decline in muscle strength, quality, and mass, affects aging population worldwide, leading to increased morbidity and mortality. Besides resistance exercise, various nutritional strategies, including omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation, have been sought to prevent this condition. This narrative review summarizes the current evidence on the effect and mechanism of n-3 PUFA on musculoskeletal health. Despite conflicting evidence, n-3 PUFA is suggested to benefit muscle mass and volume, with more evident effects with higher supplementation dose (>2 g/day). n-3 PUFA supplementation likely improves handgrip and quadriceps strength in the elderly. Improved muscle functions, measured by walking speed and time-up-to-go test, are also observed, especially with longer duration of supplementation (>6 months), although the changes are small and unlikely to be clinically meaningful. Lastly, n-3 PUFA supplementation may positively affect muscle protein synthesis response to anabolic stimuli, alleviating age-related anabolic resistance. Proposed mechanisms by which n-3 PUFA supplementation improves muscle health include 1. anti-inflammatory properties, 2. augmented expression of mechanistic target of rapamycin complex 1 (mTORC1) pathway, 3. decreased intracellular protein breakdown, 4. improved mitochondrial biogenesis and function, 5. enhanced amino acid transport, and 6. modulation of neuromuscular junction activity. In conclusion, n-3 PUFAs likely improve musculoskeletal health related to sarcopenia, with suggestive effect on muscle mass, strength, physical performance, and muscle protein synthesis. However, the interpretation of the findings is limited by the small number of participants, heterogeneity of supplementation regimens, and different measuring protocols.

A Brief Narrative Review of the Underlying Mechanisms Whereby Omega-3 Fatty Acids May Influence Skeletal Muscle: From Cell Culture to Human Interventions

Skeletal muscle is essential for human locomotion as well as maintaining metabolic homeostasis. Age-related reduction in skeletal muscle mass, strength, and function (i.e., sarcopenia) is a result of pathophysiological processes that include inflammation, alteration of molecular signaling for muscle protein synthesis and degradation, changes in insulin sensitivity, as well as altered skeletal muscle satellite cell activity. Finding strategies to mitigate skeletal muscle loss with age is deemed paramount as the percentage of the population continues to shift towards having more older adults with sarcopenia. Recent research indicates omega-3 fatty acid supplementation can influence anabolic or catabolic pathways in skeletal muscle. Our brief review will provide a synopsis of some underlying mechanisms that may be attributed to omega-3 fatty acid supplementation's effects on skeletal muscle. We will approach this review by focusing on cell culture, animal (pre-clinical models), and human studies evaluating omega-3 fatty acid supplementation, with suggestions for future research. In older adults, omega-3 fatty acids may possess some potential to modify pathophysiological pathways associated with sarcopenia; however, it is highly likely that omega-3 fatty acids need to be combined with other anabolic interventions to effectively ameliorate sarcopenia.

Microalgae Produce Antioxidant Molecules with Potential Preventive Effects on Mitochondrial Functions and Skeletal Muscular Oxidative Stress

In recent years, microalgae have become a source of molecules for a healthy life. Their composition of carbohydrates, peptides, lipids, vitamins and carotenoids makes them a promising new source of antioxidant molecules. Skeletal muscle is a tissue that requires constant remodeling via protein turnover, and its regular functioning consumes energy in the form of adenosine triphosphate (ATP), which is produced by mitochondria. Under conditions of traumatic exercise or muscular diseases, a high production of reactive oxygen species (ROS) at the origin of oxidative stress (OS) will lead to inflammation and muscle atrophy, with life-long consequences. In this review, we describe the potential antioxidant effects of microalgae and their biomolecules on mitochondrial functions and skeletal muscular oxidative stress during exercises or in musculoskeletal diseases, as in sarcopenia, chronic obstructive pulmonary disease (COPD) and Duchenne muscular dystrophy (DMD), through the increase in and regulation of antioxidant pathways and protein synthesis.

Increased Intake of Omega-3 Polyunsaturated Fatty Acids Is Associated with Reduced Odds of Low Hand Grip Strength in Korean Adults

Nutritional status is thought to be one of the modifiable risk factors for muscle health. This study investigates the association between dietary omega-3 polyunsaturated fatty acids (PUFA) intake and hand grip strength (HGS) in Korean adults. The cross-sectional analysis was performed on 18,278 participants aged ≥19 years enrolled in the Korea National Health and Nutrition Examination Survey from 2016-2019. Omega-3 PUFA consumption was positively linked to the dietary intake of nuts, fish, and shellfish in Korean adults. After adjusting for potential confounders, the results showed that increased omega-3 PUFA intake was associated with a decreased risk of low HGS (odds ratio (OR) for upper quartile (Q4) compared to Q1, men: OR = 1.42 (95% CI: 1.17-1.72), women: OR = 1.61 (1.37-1.89)). This inverse association was reported in people who did no resistance exercise or had an insufficient protein intake. In contrast, this association was not evident in adults who did resistance exercise or had sufficient protein intake. Furthermore, participants with hypertension or type 2 diabetes showed stronger associations between dietary omega-3 PUFA intake and HGS compared with other subgroups. These results suggest that dietary omega-3 PUFA intake positively related with HGS in Korean adults.

Functional Nutrients to Ameliorate Neurogenic Muscle Atrophy

Neurogenic muscle atrophy is a debilitating condition that occurs from nerve trauma in association with diseases or during aging, leading to reduced interaction between motoneurons and skeletal fibers. Current therapeutic approaches aiming at preserving muscle mass in a scenario of decreased nervous input include physical activity and employment of drugs that slow down the progression of the condition yet provide no concrete resolution. Nutritional support appears as a precious tool, adding to the success of personalized medicine, and could thus play a relevant part in mitigating neurogenic muscle atrophy. We herein summarize the molecular pathways triggered by denervation of the skeletal muscle that could be affected by functional nutrients. In this narrative review, we examine and discuss studies pertaining to the use of functional ingredients to counteract neurogenic muscle atrophy, focusing on their preventive or curative means of action within the skeletal muscle. We reviewed experimental models of denervation in rodents and in amyotrophic lateral sclerosis, as well as that caused by aging, considering the knowledge generated with use of animal experimental models and, also, from human studies.

Effectiveness of a Novel Food Composed of Leucine, Omega-3 Fatty Acids and Probiotic Lactobacillus paracasei PS23 for the Treatment of Sarcopenia in Elderly Subjects: A 2-Month Randomized Double-Blind Placebo-Controlled Trial

Sarcopenia is a complex process characterized by a progressive decrease in muscle mass and strength. Various nutrients have been shown to be effective in supporting muscular performance. This randomized clinical trial aimed to evaluate the effectiveness of a 2-month administration of food for special medical purposes composed of omega-3 fatty acids (500 mg), leucine (2.5 g), and probiotic Lactobacillus paracasei PS23 (LPPS23), on appendicular lean mass (ALM), muscle performance, inflammatory status, and amino acid profile in sarcopenic patients. A total of 60 participants (aged 79.7 ± 4.8 years and a body mass index of 22.2 ± 2.1 kg/m2) were enrolled and randomly assigned to either intervention (n = 22) or placebo group (n = 28). Comparing the differences in effects between groups (intervention minus placebo effects), ALM increased significantly in the intervention group (p < 0.05), with no discernible change in the placebo group. Similarly, significant differences were also observed for the Tinetti scale (+2.39 points, p < 0.05), the SPPB total score (+2.22 points, p < 0.05), and the handgrip strength (4.09 kg, p < 0.05). Visceral adipose tissue significantly decreased in the intervention group compared to the placebo group at 60 days −0.69 g (95% CI: −1.09, 0.29) vs. 0.27 g (95% CI: −0.11, 0.65), groups difference −0.96 (95% CI: −1.52, 0.39, p = 0.001). A statistically significant increase in levels of valine, leucine, isoleucine, and total amino acid profiles was observed in the intervention group compared with the placebo group at 60 days (p = 0.001). When taken together, these beneficial effects may be attributed to the innovative composition of this special medical-purpose food which could be considered for the treatment of sarcopenia in the elderly.

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.

Dietary omega-3 polyunsaturated fatty acid and alpha-linolenic acid are associated with physical capacity measure but not muscle mass in older women 65-72 years

Purpose

The aim was to investigate the cross-sectional association of dietary omega-3 polyunsaturated fatty acids PUFA (alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)) intake with multiple physical functions, muscle mass and fat mass in older women.

Method

Study subjects were 554 women from the Osteoporosis Risk Factor and Prevention Fracture Prevention Study, with dietary intake assessed with 3-day food record. Body composition was measured by dual-energy X-ray absorptiometry. Physical function measures included walking speed 10 m, chair rises, one leg stance, knee extension, handgrip strength and squat. Short physical performance battery (SPPB) score was defined based on the European working group on sarcopenia criteria.

Results

The multivariable adjusted models showed statistically significant associations for dietary ALA with higher SPPB (β = 0.118, P = 0.024), knee extension force at baseline (β = 0.075, P = 0.037) and lower fat mass (β = − 0.081, P = 0.034), as well as longer one-leg stance (β = 0.119, P = 0.010), higher walking speed (β = 0.113, P = 0.047), and ability to squat to the ground (β = 0.110, P = 0.027) at baseline. Total dietary omega-3 PUFA was associated with better SPPB (β = 0.108, P = 0.039), one-leg stance (β = 0.102, P = 0.041) and ability to squat (β = 0.110, P = 0.028), and with walking speed (β = 0.110, P = 0.028). However, associations for dietary EPA and DHA with physical function and body composition were not significant.

Conclusion

Dietary omega-3 and ALA, but not EPA and DHA, were positively associated with muscle strength and function in older women. The intake of omega-3 and its subtypes was not associated with muscle mass. Longitudinal studies are needed to show whether omega-3 intake may be important for muscle function in older women.

Sarcopenia; functional concerns, molecular mechanisms involved, and seafood as a nutritional intervention - review article

The fundamental basis for the human function is provided by skeletal muscle. Advancing age causes selective fiber atrophy, motor unit loss, and hybrid fiber formation resulting in hampered mass and strength, thus referred to as sarcopenia. Influence on the loss of independence of aged adults, contribute toward inclined healthcare costs conveys the injurious impact. The current understating of age-related skeletal muscle changes are addressed in this review, and further discusses mechanisms regulating protein turnover, although they do not completely define the process yet. Moreover, the reduced capacity of muscle regeneration due to impairment of satellite cell activation and proliferation with neuronal, immunological, hormonal factors were brought into the light of attention. Nevertheless, complete understating of sarcopenia requires disentangling it from disuse and disease. Nutritional intervention is considered a potentially preventable factor contributing to sarcopenia. Seafood is a crucial player in the fight against hunger and malnutrition, where it consists of macro and micronutrients. Hence, the review shed light on seafood as a nutritional intrusion in the treatment and prevention of sarcopenia. Understanding multiple factors will provide therapeutic targets in the prevention, treatment, and overcoming adverse effects of sarcopenia.

Saltwater fish but not freshwater fish consumption is positively related to handgrip strength: The TCLSIH Cohort Study

Fish contain many important nutrients and are primarily known for high n-3 polyunsaturated fatty acids (n-3 PUFA) content. Studies have shown that supplementation of fish oil-derived n-3 PUFA improves muscle mass and strength. Here, we hypothesized that fish consumption might improve muscle strength. To test this hypothesis, we performed this cross-sectional study (n = 29,084) in Tianjin, China. The frequency of fish consumption was assessed using a valid self-administered food frequency questionnaire. Handgrip strength (HGS) was used as the indicator of muscle strength, and was measured using a handheld digital dynamometer. Analysis of covariance was used to examine the relationship between fish consumption and HGS. In men, after adjusted potential confounding factors, the least square means (95% confidence intervals) of HGS across saltwater fish consumption categories were 41.5 (41.1, 43.7) kg for <1 time/week, 44.6 (43.2, 45.8) kg for 1 time/week, and 44.7 (43.3, 46.1) kg for ≥2 to 3 times/week (P for trend <0.001). In men, the least square means (95% confidence intervals) of HGS across the ascending quartiles of dietary n-3 PUFA intake were 43.6 (43.2, 44.4) kg, 43.7 (43.2, 44.6) kg, 44.4 (43.0, 45.8) kg, and 44.6 (43.1, 46.0) kg (P for trend <0.01). The results showed that saltwater fish consumption was positively related to HGS in men, but not in women, suggesting that saltwater fish contain nutrients that may be used to improve HGS.

Functional Frailty, Dietary Intake, and Risk of Malnutrition. Are Nutrients Involved in Muscle Synthesis the Key for Frailty Prevention?

Frailty is a reversible condition, which is strongly related to physical function and nutritional status. Different scales are used to screened older adults and their risk of being frail, however, Short Physical Performance Battery (SPPB) may be more adequate than others to measure physical function in exercise interventions and has been less studied. Thus, the main aims of our study were: (1) to describe differences in nutritional intakes by SPPB groups (robust, pre-frail and frail); (2) to study the relationship between being at risk of malnourishment and frailty; and (3) to describe differences in nutrient intake between those at risk of malnourishment and those without risk in the no-frail individuals. One hundred one participants (80.4 ± 6.0 year old) were included in this cross-sectional study. A validated semi-quantitative food frequency questionnaire was used to determine food intake and Mini Nutritional Assessment to determine malnutrition. Results revealed differences for the intake of carbohydrates, n-3 fatty acids (n3), and saturated fatty acids for frail, pre-frail, and robust individuals and differences in vitamin D intake between frail and robust (all p < 0.05). Those at risk of malnutrition were approximately 8 times more likely to be frail than those with no risk. Significant differences in nutrient intake were found between those at risk of malnourishment and those without risk, specifically in: protein, PUFA n-3, retinol, ascorbic acid, niacin equivalents, folic acid, magnesium, and potassium, respectively. Moreover, differences in alcohol were also observed showing higher intake for those at risk of malnourishment (all p < 0.05). In conclusion, nutrients related to muscle metabolism showed to have different intakes across SPPB physical function groups. The intake of these specific nutrients related with risk of malnourishment need to be promoted in order to prevent frailty.

Effects of n-3 EPA and DHA supplementation on fat free mass and physical performance in elderly. A systematic review and meta-analysis of randomized clinical trial

The most studied n-3 polyunsaturated fatty acids (n-3 PUFAs) are eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), and their intake seem to have a positive effect on skeletal muscle. This systematic review and meta-analysis aims to investigate the effect of n-3 EPA and DHA supplementation on fat free mass, and on different indexes of physical performance in the elderly. Eligible studies included RCT studies that investigated EPA and DHA intervention. Random-effects models have been used in order to estimate pooled effect sizes, the mean differences, and 95 % CIs. Findings from 14 studies (n = 2220 participants) lasting from 6 to 144 weeks have been summarized in this article. The meta-analyzed mean differences for random effects showed that daily n-3 EPA + DHA supplementation (from 0.7 g to 3.36 g) decreases the time of Time Up and Go (TUG) test of -0.28 s (CI 95 %-0.43, -0.13;). No statistically significant effects on physical performance indicators, such as 4-meter Walking Test, Chair Rise Test and Handgrip Strength, have been found. The fat free mass follows an improvement trend of +0.30 kg (CI 95 % -0.39, 0.99) but not statistically significant. N-3 EPA + DHA supplementation could be a promising strategy in order to enhance muscle quality and prevent or treat frailty.

Better muscle strength with healthy eating

PURPOSE

Hand grip strength (HGS) can predict physical function in next year when it is positively associated with nutritional and health status. This study aimed to determine the relationship between the healthy eating index (HEI)-2015 and hand grip strength.

METHODS

This cross-sectional study was conducted on data from 4010 participants in the Ravansar non-communicable disease (RaNCD) cohort study. HGS was measured using a hand-held hydraulic hand grip dynamometer. HEI-2015 was calculated using data from the food frequency questionnaire.

RESULTS

The mean of total HEI-2015 score was significantly higher in participants with an optimal HGS than in participants with a weak HGS (P = 0.006). Higher adherence to healthy eating was associated with optimal muscle strength (OR 1.26; CI 95% 1.02-1.62). This association was remained after being adjusted for potential confounders (P = 0.01). Among the HEI-2015 components, we only found association between whole fruit, added sugar, and HGS (P = 0.01, 0.019).

CONCLUSIONS

Our findings indicated that adherence to HEI-2015 could promote muscle strength. Among the HEI-2015 components, higher intake of whole fruit and lower adherence to added sugar had significantly positive effects on HGS.

LEVEL OF EVIDENCE

Level V, descriptive cross-sectional study.

Effect of n-3 polyunsaturated fatty acid supplementation on muscle mass and function with aging: A meta-analysis of randomized controlled trials✰

The results of randomized controlled trials (RCTs) investigating supplemental n-3 polyunsaturated fatty acids (PUFA) on muscle mass and function have been inconsistent. The present study aimed to quantitatively evaluate the effect of n-3 PUFA supplementation on indicators of muscle mass and function in healthy subjects. A systematic literature search was conducted up to July 2020 with databases of PubMed and Web of science. The random-effects model was implemented to calculate the weighted mean difference of net change of indicators regarding muscle mass and function. A total of nine studies (thirteen treatment groups) with 2067 participants were included for data analysis. The summary estimate showed that n-3 PUFA supplementation significantly increased the grip strength (1.17 kg; 95% CI: 0.27, 2.08 kg). Non-significant effect was observed with respect to muscle mass parameters, including fat mass (-0.67 kg; 95% CI: -2.20, 0.87 kg) and lean mass (0.33 kg; 95% CI: -0.35, 1.00 kg). Regarding muscle function indicators, there were non-significant effects on walking speed (-0.01 m•s^-1; 95% CI: -0.03, 0.01 m•s^-1), time up and go test (-0.25 s; 95% CI: -0.55, 0.04 s), respectively. The findings of this study indicated that supplementation with n-3 PUFA might have beneficial effects to improve muscle mass and function in healthy participants. However, there was no significant improvement in the subjects' muscle mass. Whether n-3 PUFA supplementation has favorable effects in participants with sarcopenia are warranted to be further investigated.

Eicosapentaenoic acid enhances skeletal muscle hypertrophy without altering the protein anabolic signaling pathway

This study aimed to examine the effect of eicosapentaenoic acid (EPA) on skeletal muscle hypertrophy induced by muscle overload and the associated intracellular signaling pathways. Male C57BL/6J mice were randomly assigned to oral treatment with either EPA or corn oil for 6 weeks. After 4 weeks of treatment, the gastrocnemius muscle of the right hindlimb was surgically removed to overload the plantaris and soleus muscles for 1 or 2 weeks. We examined the effect of EPA on the signaling pathway associated with protein synthesis using the soleus muscles. According to our analysis of the compensatory muscle growth, EPA administration enhanced hypertrophy of the soleus muscle but not hypertrophy of the plantaris muscle. Nevertheless, EPA administration did not enhance the expression or phosphorylation of Akt, mechanistic target of rapamycin (mTOR), or S6 kinase (S6K) in the soleus muscle. In conclusion, EPA enhances skeletal muscle hypertrophy, which can be independent of changes in the AKT-mTOR-S6K pathway.

Effects of Omega-3 Fatty Acids on Muscle Mass, Muscle Strength and Muscle Performance among the Elderly: A Meta-Analysis

There is increasing evidence showing the role of fatty acids and their derived lipid intermediates in the regulation of skeletal muscle mass synthesis and function. However, the role of omega-3 fatty acids remains unclear. Therefore, we conducted a meta-analysis to evaluate the potential effects of omega-3 fatty acids on sarcopenia-related performances among the elderly. Eligible literature and reports of randomized controlled trials were comprehensively searched from the PubMed, Cochrane Library, ClinicalTrials.gov, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases until July 2018. A total of 10 articles were available for the meta-analysis. There were minor benefits for muscle mass gain (0.33 kg; 95% CI: 0.05, 0.62) and timed up and go performance (−0.30 s; 95% CI: −0.43, −0.17). Subgroup analyses regarding muscle mass and walk speed indicated that omega-3 fatty acid supplements at more than 2 g/day may contribute to muscle mass gain (0.67 kg; 95% CI: 0.16, 1.18) and improve walking speed, especially for those receiving more than 6 months of intervention (1.78 m/sec; 95% CI: 1.38, 2.17). Our findings provide some insight into the effects of omega-3 fatty acids on muscle mass, especially for those taking supplements at more than 2 g/day. We also observed that a long period of omega-3 fatty acids supplementation may improve walking speed.

Nonalcoholic fatty liver disease and sarcopenia: pathophysiological connections and therapeutic implications

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is currently one of the most common liver diseases worldwide. Recent data suggest that loss of skeletal muscle mass and function (i.e. sarcopenia) is highly prevalent and frequently overlooked in NAFLD patients. Experimental and clinical data suggest that the relationship between NAFLD and sarcopenia is pathophysiologically complex and bi-directional and there is a growing interest in unveiling how sarcopenia could influence NAFLD development and progression.

AREAS COVERED

PubMed/MEDLINE was searched for articles related to concomitant occurrence of NAFLD and sarcopenia between January 2013 and April 2020. Areas covered in this review include: (1) updated sarcopenia diagnosis strategy, (2) discussion of current data on pathophysiological connections between NAFLD and sarcopenia, and (3) analysis of current and future therapeutic implications of this knowledge.

EXPERT OPINION

Clinical studies describe a consistent association between NAFLD and sarcopenia, although a cause-effect relation remains to be determined. Active implementation of current diagnosis algorithms and optimized treatment can prevent sarcopenia related complications in subjects with NAFLD. Pathogenic pathways implicated in this relation are multiple and complex, a better understanding of them can provide novel biomarkers and targeted therapies that will hopefully have an important impact in NAFLD management.

Dietary fish oil supplement induces age-specific contractile and proteomic responses in muscles of male rats

Background

Dietary fish oil (DFO) has been identified as a micronutrient supplement with the potential to improve musculoskeletal health in old age. Few data are available for effects of DFO on muscle contractility, despite the significant negative impact of muscle weakness on age-related health outcomes. Accordingly, the effects of a DFO intervention on the contractile function and proteomic profile of adult and aged in an animal model of aging were investigated.

Methods

This preliminary study evaluated 14 adult (8 months) and 12 aged (22 months) male, Sprague-Dawley rats consuming a DFO-supplemented diet or a control diet for 8 weeks (7 adult and 6 aged/dietary group). Animal weight, food intake and grip strength were assessed at the start and end of the FO intervention. In situ force and contractile properties were measured in the medial gastrocnemius muscle following the intervention and muscles were processed for 2-D gel electrophoresis and proteomic analysis via liquid chromatography with tandem mass spectrometry, confirmed by immunoblotting. Effects of age, diet and age x diet interaction were evaluated by 2-way ANOVA.

Results

A significant (P = 0.022) main effect for DFO to increase (~ 15%) muscle contractile force was observed, without changes in muscle mass. Proteomic analysis revealed a small number of proteins that differed across age and dietary groups at least 2-fold, most of which related to metabolism and oxidative stress. In seven of these proteins (creatine kinase, triosephosphate isomerase, pyruvate kinase, parvalbumin, beta-enolase, NADH dehydrogenase and Parkin7/DJ1), immunoblotting corroborated these findings. Parvalbumin showed only an effect of diet (increased with DFO) (P = 0.003). Significant age x diet interactions were observed in the other proteins, generally demonstrating increased expression in adult and decreased expression aged rats consuming DFO (all P > 0.011). However, correlational analyses revealed no significant associations between contractile parameters and protein abundances.

Conclusions

Results of this preliminary study support the hypothesis that DFO can enhance musculoskeletal health in adult and aged muscles, given the observed improvement in contractile function. The fish oil supplement also alters protein expression in an age-specific manner, but the relationship between proteomic and contractile responses remains unclear. Further investigation to better understand the magnitude and mechanisms muscular effects of DFO in aged populations is warranted.

Undaria pinnatifida extract feeding increases exercise endurance and skeletal muscle mass by promoting oxidative muscle remodeling in mice

Dietary habits can alter the skeletal muscle performance and mass, and Undaria pinnatifida extracts are considered a potent candidate for improving the muscle mass and function. Therefore, in this study, we aimed to assess the effect of U pinnatifida extracts on exercise endurance and skeletal muscle mass. C57BL/6 mice were fed a 0.25% U pinnatifida extract-containing diet for 8 weeks. U pinnatifida extract-fed mice showed increased running distance, total running time, and extensor digitorum longus and gastrocnemius muscle weights. U pinnatifida extract supplementation upregulated the expression of myocyte enhancer factor 2C, oxidative muscle fiber markers such as myosin heavy chain 1 (MHC1), and oxidative biomarkers in the gastrocnemius muscles. Compared to the controls, U pinnatifida extract-fed mice showed larger mitochondria and increased gene and protein expression of molecules involved in mitochondrial biogenesis and oxidative phosphorylation, including nuclear respiratory factor 2 and mitochondrial transcription factor A. U pinnatifida extract supplementation also increased the mRNA expression of angiogenesis markers, including VEGFa, VEGFb, FGF1, angiopoietin 1, and angiopoietin 2, in the gastrocnemius muscles. Importantly, U pinnatifida extracts upregulated the estrogen-related receptor γ and peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC-1α)/AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) networks, which are partially increased by fucoxanthin, hesperetin, and caffeic acid treatments. Collectively, U pinnatifida extracts enhance mitochondrial biogenesis, increase oxidative muscle fiber, and promote angiogenesis in skeletal muscles, resulting in improved exercise capacity and skeletal muscle mass. These effects are attributable to fucoxanthin, hesperetin, and caffeic acid, bioactive components of U pinnatifida extracts.

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.

Clinical relevance of skeletal muscle abnormalities in patients with cirrhosis

Recent advances in body composition evaluation have demonstrated abnormalities in skeletal muscle in patients with cirrhosis. Sarcopenia (severe muscle depletion) and myosteatosis (pathological fat accumulation in muscle) are prevalent muscle abnormalities in patients with cirrhosis that confer poor prognosis. Sarcopenia has become a well-defined factor for adverse clinical outcomes pre- and post-liver transplantation and emerging evidence has suggested the prognostic significance of myosteatosis in predicting mortality and overt hepatic encephalopathy in patients with cirrhosis. Advances in the understating of these muscle abnormalities might help improve therapeutic interventions to correct them and potentially improve outcomes of patients with cirrhosis. Moreover, inclusion of these muscle abnormalities within the current organ allocation policies might lead to a better mortality risk assessment in patients awaiting liver transplant and even to a decrease in the rates of futile liver transplants. This review summarizes the current knowledge regarding the modalities to evaluate skeletal muscle abnormalities in cirrhosis, the incidence and clinical impact of these abnormalities in cirrhosis; existing and potential novel therapeutic strategies are also discussed.

Effect of Long-Term Omega 3 Polyunsaturated Fatty Acid Supplementation with or without Multidomain Lifestyle Intervention on Muscle Strength in Older Adults: Secondary Analysis of the Multidomain Alzheimer Preventive Trial (MAPT)

Background: The benefits of long-term omega 3 polyunsaturated fatty acid (ω3-PUFA) supplementation on muscle strength in older adults remains to be investigated. Objectives: We assessed the effect of ω3-PUFA supplementation and a multidomain (physical activity, cognitive training, and nutritional advice), alone or in combination, compared with placebo, on muscle strength. We also hypothesized that ω3-PUFA supplementation resulted in additional benefit in participants with a low docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) erythrocyte level at baseline and high adherence to the multidomain intervention sessions. Design: We performed secondary analyses of the Multidomain Alzheimer Preventive Trial (MAPT), a 3-year, multicenter, randomized, placebo-controlled trial with four parallel groups. Participants were non-demented, aged 70 years or older. They were recruited in 13 memory clinics in France and Monaco between 30 May 2008 and 24 February 2011. Participants were randomly assigned to either ω3-PUFA alone (two capsules a day providing a total daily dose of 800 mg DHA and 225 mg EPA), ω3-PUFA plus the multidomain intervention (43 group sessions integrating advice for physical activity (PA), and nutrition, cognitive training, and three preventive consultations), the multidomain intervention plus placebo, or placebo alone. Our primary outcome was the change from baseline to 36 months of the muscle strength assessed with the repeated chair stand test and handgrip strength. Results: A total of 1680 participants (75.34 years ± 4.42) were randomized. In the modified intention-to-treat population (n = 1679), no significant differences at 3-year follow-up were observed in the repeated chair stand test score between any of the three intervention groups and the placebo group. The between-group differences compared with placebo were −0.05388 (−0.6800 to 0.5723; Standard Error, SE = 0.3192; p = 0.8660) for the ω3-PUFA group, −0.3936 (−1.0217 to 0.2345; SE = 0.3180; p = 0.2192) for the multidomain intervention plus placebo group, and −0.6017 (−1.2255 to 0.02222; SE = 0.2092; p = 0.3202) for the combined intervention group. No significant effect was also found for the handgrip strength. Sensitivity analyses performed among participants with low (DHA+EPA) erythrocyte level at baseline (first quartile vs. others) or highly adherent participants (≥75% of the multidomain intervention sessions) revealed similar results. Conclusion: Low dose ω3-PUFA supplementation, either alone or in combination with a multidomain lifestyle intervention comprising physical activity counselling, had no significant effects on muscle strength over 3 years in elderly people.

Omega-3 Fatty Acids-Enriched Fish Oil Activates AMPK/PGC-1α Signaling and Prevents Obesity-Related Skeletal Muscle Wasting

Obesity is known to cause skeletal muscle wasting. This study investigated the effect and the possible mechanism of fish oil on skeletal muscle wasting in an obese rat model. High-fat (HF) diets were applied to induce the defects of lipid metabolism in male Sprague-Dawley rats with or without substitution of omega-3 fatty acids-enriched fish oil (FO, 5%) for eight weeks. Diets supplemented with 5% FO showed a significant decrease in the final body weight compared to HF diet-fed rats. The decreased soleus muscle weights in HF diet-fed rats could be improved by FO substitution. The decreased myosin heavy chain (a muscle thick filament protein) and increased FOXO3A and Atrogin-1 (muscle atrophy-related proteins) protein expressions in soleus muscles of HF diet-fed rats could also be reversed by FO substitution. FO substitution could also significantly activate adenosine monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation, peroxisome-proliferator-activated receptor-γ (PPARγ) coactivator 1α (PGC-1α), and PPARγ protein expression and lipoprotein lipase (LPL) mRNA expression in soleus muscles of HF diet-fed rats. These results suggest that substitution of FO exerts a beneficial improvement in the imbalance of lipid and muscle metabolisms in obesity. AMPK/PGC-1α signaling may play an important role in FO-prevented obesity-induced muscle wasting.

The role of omega-3 in the prevention and treatment of sarcopenia

Sarcopenia is a geriatric syndrome with increasing importance due to the aging of the population. It is known to impose a major burden in terms of morbidity, mortality and socio-economic costs. Therefore, adequate preventive and treatment strategies are required. Progressive resistance training and protein supplementation are currently recommended for the prevention and treatment of sarcopenia. Omega-3 polyunsaturated fatty acids (PUFAs) might be an alternative therapeutic agent for sarcopenia due to their anti-inflammatory properties, which target the ‘inflammaging’, the age-related chronic low-grade inflammation which is assumed to contribute to the development of sarcopenia. In addition, omega-3 PUFAs may also have an anabolic effect on muscle through activation of the mTOR signaling and reduction of insulin resistance. This narrative review provides an overview of the current knowledge about omega-3 PUFAs and their role in the prevention and treatment of sarcopenia. We conclude that there is growing evidence for a beneficial effect of omega-3 PUFAs supplementation in sarcopenic older persons, which may add to the effect of exercise and/or protein supplementation. However, the exact dosage, frequency and use (alone or combined) in the treatment and prevention of sarcopenia still need further exploration.

Dietary Patterns, Skeletal Muscle Health, and Sarcopenia in Older Adults

In recent decades, the significance of diet and dietary patterns (DPs) for skeletal muscle health has been gaining attention in ageing and nutritional research. Sarcopenia, a muscle disease characterised by low muscle strength, mass, and function is associated with an increased risk of functional decline, frailty, hospitalization, and death. The prevalence of sarcopenia increases with age and leads to high personal, social, and economic costs. Finding adequate nutritional measures to maintain muscle health, preserve function, and independence for the growing population of older adults would have important scientific and societal implications. Two main approaches have been employed to study the role of diet/DPs as a modifiable lifestyle factor in sarcopenia. An a priori or hypothesis-driven approach examines the adherence to pre-defined dietary indices such as the Mediterranean diet (MED) and Healthy Eating Index (HEI)—measures of diet quality—in relation to muscle health outcomes. A posteriori or data-driven approaches have used statistical tools—dimension reduction methods or clustering—to study DP-muscle health relationships. Both approaches recognise the importance of the whole diet and potential cumulative, synergistic, and antagonistic effects of foods and nutrients on ageing muscle. In this review, we have aimed to (i) summarise nutritional epidemiology evidence from four recent systematic reviews with updates from new primary studies about the role of DPs in muscle health, sarcopenia, and its components; (ii) hypothesise about the potential mechanisms of ‘myoprotective’ diets, with the MED as an example, and (iii) discuss the challenges facing nutritional epidemiology to produce the higher level evidence needed to understand the relationships between whole diets and healthy muscle ageing.

Sarcopenia in Ovarian Cancer Patients, Oncologic Outcomes Revealing the Importance of Clinical Nutrition: Review of Literature

INTRODUCTION

Ovarian cancer is the leading cause of death among gynecological malignancies. Its usual clinical manifestation is at advanced stages, with nutritional impairment, weight loss, and a consequent decline in skeletal muscle mass and strength (defined as sarcopenia). The relationship between sarcopenia and decreased survival was demonstrated not only in ovarian cancer but also in other cancer types, such as hepatocellular, pancreatic, lung, colon, cervical, metastatic breast, and renal cancer. The aim of this study is to review the current evidence regarding the relationship between sarcopenia and the surgical and oncological outcomes in ovarian cancer patients.

METHODS

The systematic search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRSIMA) statement. The terms "SARCOPENIA" AND "OVARIAN CANCER" were systematically used to search PubMed and Scopus databases. Original reports in English language were identified, with the purpose to include all relevant papers regarding the role of sarcopenia and indicators of skeletal muscle quality assessment in gynecological ovarian cancer.

RESULTS

A total of 9 studies were considered eligible for the present review. The strength of recommendation was moderate and the level of evidence was low in all selected articles. No prospective studies were conducted and most of the papers were case-control series comparing ovarian cancer sarcopenic population vs. non sarcopenic population.

CONCLUSIONS

Sarcopenia appears to have an important role in oncological outcomes of ovarian cancer patients. However, sarcopenia occurrence during disease history and mechanisms underlying the possible impairment in prognosis should be better investigated. Prospective trials are awaited in order to obtain a better insight in this topic.

An Update on Protein, Leucine, Omega-3 Fatty Acids, and Vitamin D in the Prevention and Treatment of Sarcopenia and Functional Decline

Aging is associated with sarcopenia and functional decline, leading to frailty and disability. As a modifiable risk factor, nutrition may represent a target for preventing or postponing the onset of these geriatric conditions. Among nutrients, high-quality protein, leucine, vitamin D, and omega-3 polyunsaturated fatty acids (n-3 PUFA) are of particular interest for their demonstrated effects on skeletal muscle health. This narrative review aims to examine the recent observational and interventional evidence on the associations and the role of these nutrients in the muscle mass, strength, mobility, and physical function of free-living older adults, who are either healthy or at risk of frailty. Recent evidence supports a higher protein intake recommendation of 1.0⁻1.2 g/kg/day in healthy older adults; an evenly distributed mealtime protein intake or minimal protein per meal may be beneficial. In addition, vitamin D supplementation of 800⁻1000 IU, particularly when vitamin D status is low, and doses of ~3 g/day of n-3 PUFA may be favorable for physical function, muscle mass, and strength. Reviewed studies are highly heterogenous, yet the quantity, quality, and timing of intakes should be considered when designing intervention studies. Combined protein, leucine, vitamin D, and n-3 PUFA supplements may convey added benefits and may represent an intervention strategy in the prevention of sarcopenia and functional decline.

Sarcopenia

Sarcopenia is defined as a combination of low muscle mass with low muscle function. The term was first used to designate the loss of muscle mass and performance associated with aging. Now, recognized causes of sarcopenia also include chronic disease, a physically inactive lifestyle, loss of mobility, and malnutrition. Sarcopenia should be differentiated from cachexia, which is characterized not only by low muscle mass but also by weight loss and anorexia. Sarcopenia results from complex and interdependent pathophysiological mechanisms that include aging, physical inactivity, neuromuscular compromise, resistance to postprandial anabolism, insulin resistance, lipotoxicity, endocrine factors, oxidative stress, mitochondrial dysfunction, and inflammation. The prevalence of sarcopenia ranges from 3% to 24% depending on the diagnostic criteria used and increases with age. Among patients with rheumatoid arthritis 20% to 30% have sarcopenia, which correlates with disease severity. Sarcopenia exacts a heavy toll of functional impairment, metabolic disorders, morbidity, mortality, and healthcare costs. Thus, the consequences of sarcopenia include disability, quality of life impairments, falls, osteoporosis, dyslipidemia, an increased cardiovascular risk, metabolic syndrome, and immunosuppression. The adverse effects of sarcopenia are particularly great in patients with a high fat mass, a condition known as sarcopenic obesity. The diagnosis of sarcopenia rests on muscle mass measurements and on functional tests that evaluate either muscle strength or physical performance (walking, balance). No specific biomarkers have been identified to date. The management of sarcopenia requires a multimodal approach combining a sufficient intake of high-quality protein and fatty acids, physical exercise, and antiinflammatory medications. Selective androgen receptor modulators and anti-myostatin antibodies are being evaluated as potential stimulators of muscle anabolism.