Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) in Muscle Damage and Function

Dietary Supplementation with n-3 Polyunsaturated Fatty Acids Delays the Phenotypic Manifestation of Krabbe Disease and Partially Restores Lipid Mediator Production in the Brain-Study in a Mouse Model of the Disease

Lipid mediators from fatty acid oxidation have been shown to be associated with the severity of Krabbe disease (KD), a disorder linked to mutations in the galactosylceramidase (GALC) gene. This study aims to investigate the effects of n-3 polyunsaturated fatty acid (PUFA) supplementation on KD traits and fatty acid metabolism using Twitcher (Tw) animals as a natural model for KD. Wild-type (Wt), heterozygous (Ht), and affected Tw animals were treated orally with 36 mg n-3 PUFAs/kg body weight/day from 10 to 35 days of life. The end product of PUFA peroxidation (8-isoprostane), the lipid mediator involved in the resolution of inflammatory exudates (resolvin D1), and the total amount of n-3 PUFAs were analyzed in the brains of mice. In Tw mice, supplementation with n-3 PUFAs delayed the manifestation of disease symptoms (p < 0.0001), and in the bran, decreased 8-isoprostane amounts (p < 0.0001), increased resolvin D1 levels (p < 0.005) and increased quantity of total n-3 PUFAs (p < 0.05). Furthermore, total brain n-3 PUFA levels were associated with disease severity (r = -0.562, p = 0.0001), resolvin D1 (r = 0.712, p < 0.0001), and 8-isoprostane brain levels (r = -0.690, p < 0.0001). For the first time in a natural model of KD, brain levels of n-3 PUFAs are shown to determine disease severity and to be involved in the peroxidation of brain PUFAs as well as in the production of pro-resolving lipid mediators. It is also shown that dietary supplementation with n-3 PUFAs leads to a slowing of the phenotypic presentation of the disease and restoration of lipid mediator production.

Omega-3 Fatty Acid Supplementation on Post-Exercise Inflammation, Muscle Damage, Oxidative Response, and Sports Performance in Physically Healthy Adults-A Systematic Review of Randomized Controlled Trials

Omega-3 is a family of n-3 polyunsaturated fatty acids (PUFAs), which have been used to treat a wide variety of chronic diseases, due mainly to their antioxidant and anti-inflammatory properties, among others. In this context, omega-3 could be post-exercise recovery agent and sports supplement that could improve performance by preserving and promoting skeletal muscle mass and strength. No conclusive evidence, however, exists about the potential effects of omega-3 on post-exercise biomarkers and sports performance in physically healthy adults. Based on the PRISMA in Exercise, Rehabilitation, Sports Medicine, and Sports Science (PERSiST) guidelines, we systematically reviewed studies indexed in Web of Science, Scopus, and Medline to assess the effects of omega-3 on post-exercise inflammation, muscle damage, oxidant response, and sports performance in physically healthy adults. The search was performed on original articles published in the last 10 years up to 5 May 2024, with a controlled trial design in which omega-3 supplementation was compared with a control group. Among 14,971 records identified in the search, 13 studies met the selection criteria. The duration of the interventions ranged from 1 day to 26 weeks of supplementation and the doses used were heterogeneous. Creatine kinase (CK) and lactate dehydrogenase (LDH) were significantly higher (p < 0.05) in the control group in 3 of the 4 studies where these markers were analyzed. C-reactive protein (CRP) was significantly higher (p < 0.05) in the control group of 2 of the 13 studies where this marker was analyzed. The delayed onset muscle soreness (DOMS) gave mixed results. Interleukin 6 (IL-6) showed improvements with supplementation, but tumor necrosis factor-α (TNF-α) displayed no differences. The consumption of n-3 PUFAs improved some indicators of oxidative stress such as reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio. Additional evidence is needed to establish clear recommendations regarding the dose and length of n-3 PUFA supplements. These may benefit the post-exercise inflammatory response, mitigate muscle damage, and decrease oxidative stress caused by exercise. However, studies did not evaluate omega-3 status at baseline or following supplementation and therefore the observations must be treated with caution.

Eicosapentaenoic acid-mediated activation of PGAM2 regulates skeletal muscle growth and development via the PI3K/AKT pathway

Eicosapentaenoic acid regulates glucose uptake in skeletal muscle and significantly affects whole-body energy metabolism. However, the underlying molecular mechanism remains unclear. Here we report that eicosapentaenoic acid activates phosphoglycerate mutase 2, which mediates the conversion of 2-phosphoglycerate into 3-phosphoglycerate. This enzyme plays a pivotal role in glycerol degradation, thereby facilitating the proliferation and differentiation of satellite cells in skeletal muscle. Interestingly, phosphoglycerate mutase 2 inhibits mitochondrial metabolism, promoting the formation of fast-type muscle fibers. Treatment with eicosapentaenoic acid and phosphoglycerate mutase 2 knockdown induced opposite transcriptomic changes, most of which were enriched in the PI3K-AKT signaling pathway. Phosphoglycerate mutase 2 activated the PI3K-AKT signaling pathway, which inhibited the phosphorylation of FOXO1, and, in turn, inhibited mitochondrial function and promoted the formation of fast-type muscle fibers. Our results suggest that eicosapentaenoic acid promotes skeletal muscle growth and regulates glucose metabolism by targeting phosphoglycerate mutase 2 and activating the PI3K/AKT signaling pathway.

Nutritional Strategies for Muscle Atrophy: Current Evidence and Underlying Mechanisms

Skeletal muscle can undergo detrimental changes in various diseases, leading to muscle dysfunction and atrophy, thus severely affecting people's lives. Along with exercise, there is a growing interest in the potential of nutritional support against muscle atrophy. This review provides a brief overview of the molecular mechanisms driving skeletal muscle atrophy and summarizes recent advances in nutritional interventions for preventing and treating muscle atrophy. The nutritional supplements include amino acids and their derivatives (such as leucine, β-hydroxy, β-methylbutyrate, and creatine), various antioxidant supplements (like Coenzyme Q10 and mitoquinone, resveratrol, curcumin, quercetin, Omega 3 fatty acids), minerals (such as magnesium and selenium), and vitamins (such as vitamin B, vitamin C, vitamin D, and vitamin E), as well as probiotics and prebiotics (like Lactobacillus, Bifidobacterium, and 1-kestose). Furthermore, the study discusses the impact of a combined approach involving nutritional support and physical therapy to prevent muscle atrophy, suggests appropriate multi-nutritional and multi-modal interventions based on individual conditions to optimize treatment outcomes, and enhances the recovery of muscle function for patients. By understanding the molecular mechanisms behind skeletal muscle atrophy and implementing appropriate interventions, it is possible to enhance the recovery of muscle function and improve patients' quality of life.

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.

Metabolic fate of DHA from regio- and stereospecific positions of triacylglycerols in a long-term feeding trial in rats

This study investigated the impact of regio- and stereospecific position of docosahexaenoic acid (DHA) in dietary triacylglycerols (TAGs) on the fatty acid composition of tissues and organs in rats. Four-week feeding with TAGs containing DHA in sn-1, 2, or 3 position and palmitic acid in the remaining positions at a daily dosage of 500 mg TAG/kg body weight significantly increased the DHA content in all organs and tissues in rats, except in the brain, where the change in DHA level was not statistically significant. The group fed sn-1 DHA showed a significantly higher content of DHA in the plasma TAG than the group fed sn-3 DHA. The sn-3 DHA group had higher levels of DHA in the visceral fat compared to the sn-1, sn-2, as well as all other groups. This is the first study showing that DHA from sn-1 and sn-3 positions of dietary TAGs have differential accumulation in tissues. The new findings improved the current knowledge on the significance of TAG isomeric structure for the bioavailability and metabolic fate of DHA.

Mitigation of chronic glucotoxicity-mediated skeletal muscle atrophy by arachidonic acid

Toxicity caused by chronic hyperglycemia is a significant factor affecting skeletal muscle myogenesis, resulting in diabetic myopathy. Chronic and persistent hyperglycemia causes activation of the atrophy-related pathways in the skeletal muscles, which eventually results in inflammation and muscle degeneration. To counteract this process, various bioactive compound has been studied for their reversal or hypertrophic effect. In this study, we explored the molecular mechanisms associated with reversing glucotoxicity's effect in C2C12 cells by arachidonic acid (AA). We found a substantial increase in the pro-inflammatory cytokines and ROS production in hyperglycemic conditions, mitigated by AA supplementation. We found that AA supplementation restored protein synthesis that was downregulated under glucotoxicity conditions. AA enhanced myogenesis by suppressing high glucose induced inflammation and ROS production and enhancing protein synthesis. These results imply that AA has cytoprotective actions against hyperglycemia-induced cytotoxicity.

Biotechnological production of omega-3 fatty acids: current status and future perspectives

Omega-3 fatty acids, including alpha-linolenic acids (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), have shown major health benefits, but the human body's inability to synthesize them has led to the necessity of dietary intake of the products. The omega-3 fatty acid market has grown significantly, with a global market from an estimated USD 2.10 billion in 2020 to a predicted nearly USD 3.61 billion in 2028. However, obtaining a sufficient supply of high-quality and stable omega-3 fatty acids can be challenging. Currently, fish oil serves as the primary source of omega-3 fatty acids in the market, but it has several drawbacks, including high cost, inconsistent product quality, and major uncertainties in its sustainability and ecological impact. Other significant sources of omega-3 fatty acids include plants and microalgae fermentation, but they face similar challenges in reducing manufacturing costs and improving product quality and sustainability. With the advances in synthetic biology, biotechnological production of omega-3 fatty acids via engineered microbial cell factories still offers the best solution to provide a more stable, sustainable, and affordable source of omega-3 fatty acids by overcoming the major issues associated with conventional sources. This review summarizes the current status, key challenges, and future perspectives for the biotechnological production of major omega-3 fatty acids.

Recent Advances in Nutraceuticals for the Treatment of Sarcopenic Obesity

Sarcopenic obesity, low muscle mass, and high body fat are growing health concerns in the aging population. This review highlights the need for standardized criteria and explores nutraceuticals as potential therapeutic agents. Sarcopenic obesity is associated with insulin resistance, inflammation, hormonal changes, and reduced physical activity. These factors lead to impaired muscle activity, intramuscular fat accumulation, and reduced protein synthesis, resulting in muscle catabolism and increased fat mass. Myostatin and irisin are myokines that regulate muscle synthesis and energy expenditure, respectively. Nutritional supplementation with vitamin D and calcium is recommended for increasing muscle mass and reducing body fat content. Testosterone therapy decreases fat mass and improves muscle strength. Vitamin K, specifically menaquinone-4 (MK-4), improves mitochondrial function and reduces muscle damage. Irisin is a hormone secreted during exercise that enhances oxidative metabolism, prevents insulin resistance and obesity, and improves bone quality. Low-glycemic-index diets and green cardamom are potential methods for managing sarcopenic obesity. In conclusion, along with exercise and dietary support, nutraceuticals, such as vitamin D, calcium, vitamin K, and natural agonists of irisin or testosterone, can serve as promising future therapeutic alternatives.

Eicosapentaenoic acid and branched-chain amino acids fortified complete nutrition drink improved muscle strength in older individuals with inadequate protein intake

Background

Elevated inflammation and negative nutritional balance contribute to sarcopenia, a progressive loss of muscle mass, strength, and function. This study investigated the effect of energy supplementation and the combination of anti-inflammatory factor (eicosapentaenoic acid; EPA) and muscle-synthesis promotor (branched-chain amino acids; BCAA) on body composition, muscle, and inflammatory biomarkers in elderly with inadequate protein intake.

Methods

A randomized blinded placebo-controlled trial was conducted on 84 elderly with inadequate protein intake. The participants were randomly assigned into four groups receiving a complete nutrition drink; (1) control formula, (2) fortified with 2.2 g EPA, (3) with 2.2 g EPA and 5 g BCAA (2:1:1 of Leu: Ile: Val), and (4) with 2.2 g EPA plus 5g BCAA (4:1:1 of Leu: Ile: Val). Each subject consumed two sachets of the drink to gain 500 kcal/day and performed arm muscle exercises for 3 weeks. Body compositions and handgrip strength were measured using BIA and a dynamometer, respectively. Plasma EPA and BCAA levels were determined using LC-MS/MS to ensure compliance. Muscle protein biomarkers including histidine, β-alanine, and carnosine were measured using LC-MS/MS. Serum inflammatory (IL-6) and anti-inflammatory cytokines (IL-10) were measured by using ELISA.

Results

No symptoms and signs of adverse events were observed. The right arm muscle mass and handgrip strength were significantly increased after consuming a complete nutrition drink fortified with EPA + BCAA 2:1:1 and 4:1:1 of Leu: Ile: Val (p < 0.05 and p < 0.01, respectively. Consistently, consuming such combinatory formula non-significantly elevated carnosine with reduced histidine, and increased IL-10 with decreased IL-6. All relevant intervention groups showed a significant increase in plasma levels of BCAA and EPA.

Conclusion

Consuming a complete nutrition drink fortified with 2.2g EPA and 5g BCAA 2:1:1 or 4:1:1 of Leu: Ile: Val for 3 weeks may increase right arm muscle mass and strength in elderly with inadequate protein intake. The tendency of increased dipeptide (carnosine)/decreased free amino acid (histidine) suggests a shift toward muscle protein synthesis. The trend of decreased inflammatory/increased anti-inflammatory cytokines suggests an anti-inflammatory effect. Future long-term studies are warranted to confirm the combinatory effect of BCAA and EPA in the prevention of sarcopenia.

Clinical trial registration

Thailand Clinical Trial Registry No. TCTR20230116005.

Fatty acid amides as potential circulating biomarkers for sarcopenia

BACKGROUND

Sarcopenia is characterized by a progressive decrease in skeletal muscle mass and function with age. Given that sarcopenia is associated with various metabolic disorders, effective metabolic biomarkers for its early detection are required. We aimed to investigate the metabolic biomarkers related to sarcopenia in elderly men and perform experimental studies using metabolomics.

METHODS

Plasma metabolites from 142 elderly men, comprising a sarcopenia group and an age-matched control group, were measured using global metabolome profiling. Muscle and plasma samples from an aging mouse model of sarcopenia, as well as cell media and cell lysates during myoblast differentiation, were analysed based on targeted metabolome profiling. Based on these experimental results, fatty acid amides were quantified from human plasma as well as human muscle tissues. The association of fatty acid amide levels with sarcopenia parameters was evaluated.

RESULTS

Global metabolome profiling showed that fatty acid amide levels were significantly different in the plasma of elderly men with sarcopenia (all Ps < 0.01). Consistent with these results in human plasma, targeted metabolome profiling in an aging mouse model of sarcopenia showed decreased levels of fatty acid amides in plasma but not in muscle tissue. In addition, the levels of fatty acid amides increased in cell lysates during muscle cell differentiation. Targeted metabolome profiling in men showed decreased docosahexaenoic acid ethanolamide (DHA EA) levels in the plasma (P = 0.016) but not in the muscle of men with sarcopenia. DHA EA level was positively correlated with sarcopenia parameters such as skeletal muscle mass index (SMI) and handgrip strength (HGS) (P = 0.001, P = 0.001, respectively). The area under the receiver-operating characteristic curve (AUC) for DHA EA level ≤ 4.60 fmol/μL for sarcopenia was 0.618 (95% confidence interval [CI]: 0.532-0.698). DHA EA level ≤ 4.60 fmol/μL was associated with a significantly greater likelihood of sarcopenia (odds ratio [OR]: 2.11, 95% CI: 1.03-4.30), independent of HGS. The addition of DHA EA level to age and HGS significantly improved the AUC from 0.620 to 0.691 (P = 0.0497).

CONCLUSIONS

Our study demonstrated that fatty acid amides are potential circulating biomarkers in elderly men with sarcopenia. DHA EA, in particular, strongly related to muscle mass and strength, can be a key metabolite to become a reliable metabolic biomarker for sarcopenia. Further research on fatty acid amides will provide insights into the metabolomic changes relevant to sarcopenia from an aging perspective.

Curcumin (CUMINUP60®) mitigates exercise fatigue through regulating PI3K/Akt/AMPK/mTOR pathway in mice

Curcumin is a chemical constituent extracted from Curcuma longa L. Several clinical and preclinical studies have demonstrated that it can mitigate exercise fatigue, but the exact mechanism is still unknown. Therefore, we applied a mouse model of exercise fatigue to investigate the possible molecular mechanisms of curcumin's anti-fatigue effect. Depending on body mass, Kunming mice were randomly divided into control, caffeine (positive drug), and curcumin groups, and were given 28 days intragastric administration. Both the caffeine group and curcumin group showed significant improvement in exercise fatigue compared to the control group, as evidenced by the increase in time to exhaustion, as well as the higher quadriceps coefficient, muscle glycogen (MG) content, and increase in the expression of Akt, AMPK, PI3K, and mTOR proteins. While the curcumin group also significantly improved the exercise fatigue of the mice, demonstrating a lower AMP/ATP ratio and lactic acid (LA) content, and increased glycogen synthase (GS), and myonectin content compared to the caffeine group. Therefore, in the present study, we found that curcumin can exert a similar anti-fatigue effect to caffeine and may act by regulating energy metabolism through modulating the expression of the proteins in the PI3K/Akt/AMPK/mTOR pathway.

Cold exposure alters lipid metabolism of skeletal muscle through HIF-1α-induced mitophagy

BACKGROUND

In addition to its contractile properties and role in movement, skeletal muscle plays an important function in regulating whole-body glucose and lipid metabolism. A central component of such regulation is mitochondria, whose quality and function are essential in maintaining proper metabolic homeostasis, with defects in processes such as autophagy and mitophagy involved in mitochondria quality control impairing skeletal muscle mass and function, and potentially leading to a number of associated diseases. Cold exposure has been reported to markedly induce metabolic remodeling and enhance insulin sensitivity in the whole body by regulating mitochondrial biogenesis. However, changes in lipid metabolism and lipidomic profiles in skeletal muscle in response to cold exposure are unclear. Here, we generated lipidomic or transcriptome profiles of mouse skeletal muscle following cold induction, to dissect the molecular mechanisms regulating lipid metabolism upon acute cold treatment.

RESULTS

Our results indicated that short-term cold exposure (3 days) can lead to a significant increase in intramuscular fat deposition. Lipidomic analyses revealed that a cold challenge altered the overall lipid composition by increasing the content of triglyceride (TG), lysophosphatidylcholine (LPC), and lysophosphatidylethanolamine (LPE), while decreasing sphingomyelin (SM), validating lipid remodeling during the cold environment. In addition, RNA-seq and qPCR analysis showed that cold exposure promoted the expression of genes related to lipolysis and fatty acid biosynthesis. These marked changes in metabolic effects were associated with mitophagy and muscle signaling pathways, which were accompanied by increased TG deposition and impaired fatty acid oxidation. Mechanistically, HIF-1α signaling was highly activated in response to the cold challenge, which may contribute to intramuscular fat deposition and enhanced mitophagy in a cold environment.

CONCLUSIONS

Overall, our data revealed the adaptive changes of skeletal muscle associated with lipidomic and transcriptomic profiles upon cold exposure. We described the significant alterations in the composition of specific lipid species and expression of genes involved in glucose and fatty acid metabolism. Cold-mediated mitophagy may play a critical role in modulating lipid metabolism in skeletal muscle, which is precisely regulated by HIF-1α signaling.

Immune regulation of poly unsaturated fatty acids and free fatty acid receptor 4

Fatty acid metabolism contributes to energy supply and plays an important role in regulating immunity. Free fatty acids (FFAs) bind to free fatty acid receptors (FFARs) on the cell surface and mediate effects through the intra-cellular FFAR signaling pathways. FFAR4, also known as G-protein coupled receptor 120 (GPR120), has been identified as the primary receptor of omega-3 polyunsaturated fatty acids (ω-3 PUFAs). FFAR4 is a promising target for treating metabolic and inflammatory disorders due to its immune regulatory functions and the discovery of highly selective and efficient agonists. This review summarizes the reported immune regulatory functions of ω-3 PUFAs and FFAR4 in immune cells and immune-related diseases. We also speculate possible involvements of ω-3 PUFAs and FFAR4 in other types of inflammatory disorders.

Omega-3 index and AA/EPA ratio as biomarkers of running-related injuries: An observational study in recreational runners

ABSTRACTThe aim of this study was to examine the association between biomarkers of polyunsaturated fatty acids (PUFA), such as omega-3 (ω-3) index and arachidonic acid (AA; 20:4 ω-6)/eicosapentaenoic acid (EPA; 20:5ω-3) ratio (AA/EPA), and the prevalence of running-related injuries (RRI) in a cohort of recreational runners. We performed a retrospective, observational study of 275 non-elite runners (mean age: 41.20 ± 12.47 years) who were not supplemented with ω-3 fatty acids. The training characteristics and RRI were recorded over a period of 12 months through a self-reported questionnaire. Using whole blood samples collected by finger prick, PUFA were quantified by gas chromatography and ω-3 index and AA/EPA ratio measured. A total of 191 RRI cases were reported, with an injury prevalence rate of 50.9% in the overall population. The injured runners ran a significantly greater weekly distance than uninjured subjects (53.54 ± 25.27 km/week; p = 0.007). In a multivariate regression analysis, the lowest number of RRI was associated with higher values of ω-3 index (β = - 0.237; 95% CI - 0.308 to - 0.164; R² = 0.172; p < 0.0001), while a higher AA/EPA ratio was correlated with higher number of RRI (β = 0.019; 95% CI 0.007-0.031; R² = 0.038; p = 0.003). This study identifies ω-3 index and AA/EPA ratio as potential parameters associated with the risk of RRI. Future research is needed to confirm these results and apply specific nutritional strategies to successfully modify these biochemical variables.Trial registration: ISRCTN.org identifier: ISRCTN12847156..

Serum and diet long-chain omega-3 fatty acid nutritional status in Chinese elite athletes

Omega-3 polyunsaturated fatty acids (omega-3 PUFAs) are essential for improving the health and performance of athletes. The present study aimed to evaluate the nutritional status of omega-3 PUFAs in Chinese elite athletes by both dietary intake analysis and serum biomarker detection. A cross-sectional analysis of data from 54 elite athletes (24 men and 30 women) from Shanghai professional sports teams was conducted. A food frequency questionnaire (FFQ) was employed to analyze dietary intake, and gas chromatography-mass spectrometry (GC-MS/MS) was conducted to measure serum biomarkers of PUFAs. Correlation analysis was performed to investigate the relationships of PUFA biomarkers with diet, inflammation and oxidative stress. The results showed that the median intake of EPA + DHA among athletes was 132 mg/d, which is lower than the minimum value recommended by dietary guidelines (250 mg/d). The average serum EPA + DHA was 4.0 ± 1.1%, and the ratio of omega-6/omega-3 was 7.7 ± 1.7. Most (96.3%) of the athletes were below the targeted value of serum EPA + DHA, which is associated with a reduction in cardiovascular risk. Correlation analysis showed that the serum EPA + DHA was positively correlated with the long-term dietary intake of EPA + DHA and negatively correlated with inflammatory markers. In conclusion, the serum circulating EPA + DHA and omega-6/omega-3 ratio are effective biomarkers reflecting the nutritional status of PUFAs in athletes. Omega-3 PUFAs have a potential effect on inhibiting inflammatory markers. Hence, it is necessary for Chinese athletes to improve their suboptimal nutritional status of PUFAs through dietary intervention.

Associations between Fatty Acid Intake and Tension-Type Headache: A Cross-Sectional Study

INTRODUCTION

Patients with tension-type headache (TTH) are characterized by recurrent pain that can become disabling. Identifying the dietary triggers of headaches has led to defining dietary strategies to prevent this disease. In fact, excessive dietary intake of Omega-6 (ω-6) fatty acids, or an ω-6: ω3 ≥ 5 ratio, typical of Western diets, has been associated with a higher prevalence of headaches. The objectives of the present study were to compare dietary fatty acid intake between participants with and without chronic TTH and to investigate the association between dietary fatty acid intake, pain characteristics, and quality of life in patients with chronic TTH.

METHODS

An observational study was conducted, comparing healthy participants (n = 24) and participants diagnosed with chronic TTH for more than six months (n = 24). The variables analyzed were dietary fatty acid intake variables, the Headache Impact Test (HIT-6), and the characteristics of the headache episodes (intensity, frequency, and duration).

RESULTS

The TTH group reported a significantly higher intake of saturated fatty acids (SFAs) but similar intakes of monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), and ω-6: ω-3 ratio when compared to controls. Furthermore, in the TTH group, the Ω-6 fatty acid intake was associated with more intense headache episodes. In addition, the TTH group reported a significant impact of headaches on their activities of daily living according to the HIT-6.

CONCLUSIONS

Higher intakes of SFAs and Ω-6 fatty acids were associated with more severe headache episodes in patients with TTH. Therefore, the characteristics of the diet, in particular the dietary fatty acid intake, should be considered when treating these patients.

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.

Association between Sarcopenia and Omega-3 Polyunsaturated Fatty Acid in Patients with Hepatocellular Carcinoma

Introduction

This study aimed to validate whether preoperative sarcopenia can predict long-term outcomes in patients with hepatocellular carcinoma (HCC) and identify the associations between sarcopenia and polyunsaturated fatty acids (PUFAs).

Methods

This large, retrospective study included 353 patients who underwent hepatic resection for HCC and preoperative computed tomography scans. Skeletal muscle mass was measured at the third lumbar vertebrae. The cutoff value for sarcopenia followed the Japan Society of Hepatology's assessment criteria for sarcopenia.

Results

Ninety-three patients (26.3%) with preoperative sarcopenia were enrolled. These patients had a significantly lower body mass index (p < 0.0001) and serum albumin level (p = 0.0070) as well as a higher rate of advanced-stage cancer (p = 0.0062) than those without sarcopenia. Patients with sarcopenia had significantly shorter overall survival than the other patients before (p = 0.0001) and after (p = 0.0415) propensity score matching. The sarcopenia group was significantly associated with low levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which were categorized based on omega-3 PUFAs, compared with those in the non-sarcopenia group (p = 0.0030 and p = 0.0135).

Conclusions

We demonstrated an association between sarcopenia and the long-term prognosis in patients with HCC. Low EPA and DHA levels were associated with preoperative sarcopenia. Further prospective studies are needed to investigate whether nutritional support using omega-3 PUFAs can prevent and manage skeletal muscle mass depletion.

DHA alleviates diet-induced skeletal muscle fiber remodeling via FTO/m6A/DDIT4/PGC1α signaling

Background

Obesity leads to a decline in the exercise capacity of skeletal muscle, thereby reducing mobility and promoting obesity-associated health risks. Dietary intervention has been shown to be an important measure to regulate skeletal muscle function, and previous studies have demonstrated the beneficial effects of docosahexaenoic acid (DHA; 22:6 ω-3) on skeletal muscle function. At the molecular level, DHA and its metabolites were shown to be extensively involved in regulating epigenetic modifications, including DNA methylation, histone modifications, and small non-coding microRNAs. However, whether and how epigenetic modification of mRNA such as N6-methyladenosine (m6A) mediates DHA regulation of skeletal muscle function remains unknown. Here, we analyze the regulatory effect of DHA on skeletal muscle function and explore the involvement of m⁶A mRNA modifications in mediating such regulation.

Results

DHA supplement prevented HFD-induced decline in exercise capacity and conversion of muscle fiber types from slow to fast in mice. DHA-treated myoblasts display increased mitochondrial biogenesis, while slow muscle fiber formation was promoted through DHA-induced expression of PGC1α. Further analysis of the associated molecular mechanism revealed that DHA enhanced expression of the fat mass and obesity-associated gene (FTO), leading to reduced m6A levels of DNA damage-induced transcript 4 (Ddit4). Ddit4 mRNA with lower m6A marks could not be recognized and bound by the cytoplasmic m6A reader YTH domain family 2 (YTHDF2), thereby blocking the decay of Ddit4 mRNA. Accumulated Ddit4 mRNA levels accelerated its protein translation, and the consequential increased DDIT4 protein abundance promoted the expression of PGC1α, which finally elevated mitochondria biogenesis and slow muscle fiber formation.

Conclusions

DHA promotes mitochondrial biogenesis and skeletal muscle fiber remodeling via FTO/m⁶A/DDIT4/PGC1α signaling, protecting against obesity-induced decline in skeletal muscle function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-022-01239-w.

Muscle hypertrophy induced by N-3 PUFA supplementation in absence of exercise: a systematic review of randomized controlled trials

The use of omega-3 polyunsaturated fatty acids (n-3 PUFA) has been studied in physically active population, however, there is a lack of information about the effects of n-3 PUFA supplementation on people with a sedentary behavior or who are undergoing a period of limb immobilization. This systematic review aims to examine the effect of n-3 PUFA on lean mass and muscle protein synthesis (MPS) in absence of physical training. The PubMed, Web of Science, MEDLINE, CINAHL and SPORTDiscus databases were searched following the PRISMA guidelines. Only randomized controlled trials, at least single blind, performed with sedentary humans were considered. Seven studies on a total of 192 individuals were included. Five of the six studies which measured changes in skeletal muscle volume and mass showed higher values with n-3 PUFA. Only two studies measured skeletal muscle protein expression. Both showed beneficial effects of supplementation in muscle protein fractional synthesis rate (FSR), while no effect of n-3 PUFA was observed for mechanistic target of rapamycin (mTOR) and kinase protein (Akt). In addition, ribosomal protein S6 kinase 1 (p70s6k) improved with n-3 PUFA only in one study. Finally, the two studies which measured the skeletal muscle gene expression observed no effect of supplementation.

The relationship between dietary sulfur amino acids intake and severity and frequency of pain in Iranian patients with musculoskeletal pains, 2020

OBJECTIVE

Musculoskeletal pain conditions (MPs) are a widespread public problem that can affect 13.5% to 47% of the total population. Dietary changes can have strong effects on person's health; for instance, Sulfur amino acids (SAAs) can act as a precursor of neurotransmitters, antioxidative metabolic intermediates, such as glutathione, impact inflammation, and play a role in severity and frequency of MPs. We evaluated the relationship between dietary SAAs intake with severity and frequency of pain in patients with MPs.

RESULTS

This cross-sectional study consisted of 175 men and woman. Anthropometric measurements and pain assessments were conducted via questionnaires. Dietary data were collected using 7 days 24-h recall. ANOVA and Spearman correlation coefficients were used to examine the relationship and correlation, respectively, between exposure and outcome variables. There was a significant correlation between age, weight, waist circumference (WC), waist circumference to height (WHtR), body mass index (BMI), and severity and frequency of MPs among women. There was a correlation between age and severity of pain in men. The present study highlights a positive association between the dietary SAAs and severity of pain, even after adjusting for confounding variables.

Does the Endothelium of Competitive Athletes Benefit from Consumption of n-3 Polyunsaturated Fatty Acid-Enriched Hen Eggs?

The present study aimed to determine the effect of n-3 polyunsaturated fatty acid (PUFA)-enriched hen eggs on microvascular vasodilation, microvascular responsiveness to a stress challenge and markers of oxidative stress in competitive athletes. Competitive athletes (n=23) were divided to a control group (n=9), who consumed three regular hens’ eggs daily (249 mg n-3 PUFAs/d), and n-3 PUFAs group (n=14), who consumed three n-3 PUFA-enriched hen eggs daily (1,053 g n-3 PUFAs/d) for 3 weeks. Endothelium-dependent responses [post-occlusive reactive hyperemia (PORH) and acetylcholine-induced dilation (AChID)] and endothelium-independent responses [sodium nitroprusside-induced dilation (SNPID)] of skin microvascular blood flow were assessed by laser Doppler flowmetry in pre- and post-acute exhausting exercise (AEE) sessions. Blood pressure, serum lipid, free fatty acids profiles, and biomarkers of oxidative stress were measured before and after each dietary protocol. Consumption of serum n-3 PUFAs significantly decreased the n-6/n-3 ratio and enhanced PORH and AChID, but did not affect SNPID at rest. Furthermore, serum glutathione peroxidase and superoxide dismutase activities were significantly decreased in the n-3 PUFAs group but remained unchanged in the control group. In both groups, PORH, AChID, and SNP were significantly reduced post-AEE compared with pre-AEE, both before and after consumption of each diet. Only AChID responsiveness to AEE (ΔAChID) significantly increased following consumption of n-3 PUFAs. Overall, n-3 PUFAs supplementation as n-3 PUFA-enriched hen eggs enhanced microvascular endothelial function at rest and may contribute to adaptation to AEE in competitive athletes.

Impact of varying doses of omega-3 supplementation on muscle damage and recovery after eccentric resistance exercise

BACKGROUND

Exercise-induced muscle damage (EIMD) commonly occurs following intense resistance exercise and is associated with decrements in exercise performance and delayed muscle recovery. Thus, practical methods to attenuate EIMD would prove useful to both training and athletic populations. Omega-3 (n-3) supplementation has been shown to mitigate EIMD with evidence of increasing efficacy at higher doses (up to 6 g/day). However, data of its efficacy in trained individuals is limited. Therefore, this study investigated the effects of 6 and 8 g of n-3 supplementation on markers of muscle damage and muscle recovery after eccentric resistance exercise in resistance-trained males.

METHODS

Using a double-blind, randomized, placebo-controlled design, 26 resistance trained males (23 ± 4 years; 173.6 ± 20.5 cm; 81.9 ± 9.7 kg; 14.2 ± 3.7% body fat) supplemented with 6 (n=10) or 8 g (n=7) of n-3 polyunsaturated fatty acids, or placebo (n=9) for 33 days. On day 30, participants performed a lower body muscle-damaging eccentric resistance exercise bout. Measures of muscle performance, soreness, and damage were taken pre-exercise on day 30 as well as on days 31-33, including vertical jump height (VJH), perceived muscle soreness (PMS), hip and knee range of motion (ROM), repetitions to fatigue (RTF) at 70% 1-RM, and serum creatine kinase (CK) while participants continued to supplement until day 33.

RESULTS

There were significant differences in VJH, PMS, and serum CK following the muscle-damaging exercise bout compared to pre-exercise (p<0.05). However, there were no significant (p>0.05) differences between supplementation groups (6 g, 8 g, and placebo) at any time point post-exercise (day 31-33). There were no changes in hip and knee ROM or RTF at any time point or between groups. Vertical jump height and PMS returned to pre-exercise levels despite CK remaining elevated post-exercise.

CONCLUSIONS

Thirty-three days of 6 and 8 g of n-3 supplementation did not attenuate EIMD or enhance muscle recovery following muscle-damaging eccentric resistance exercise in resistance-trained males. Further research using various n-3 supplementation durations, doses, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) concentrations may be needed to establish its efficacy in attenuating EIMD, which may vary between trained and untrained individuals. Furthermore, while circulating CK is commonly used to assess muscle damage, elevated CK levels may not reflect muscle recovery status following muscle-damaging exercise.

Polyunsaturated Fatty Acids, Exercise, and Cancer-Related Fatigue in Breast Cancer Survivors

Cancer-related fatigue (CRF) is one of the most frequently reported and disabling symptoms in cancer survivors. With its negative impact on the activities of daily living, work, social activities, and mood, CRF causes severe impairment of quality of life. A previous study showed that omega-6 polyunsaturated fatty acid (PUFA) supplementation unexpectedly reduced CRF compared with omega-3 PUFA supplementation and that omega-6 PUFA supplementation reduced pro-inflammatory serum markers in fatigued American breast cancer survivors. Meanwhile, a recent meta-analysis of individual patient data revealed significant benefits of exercise interventions on CRF. Recently, we completed our randomized controlled trial among early-stage Japanese breast cancer survivors, in which we examined the effect of baseline blood PUFA characteristics on change in CRF during the 12-week trial by exercise group and confirmed that increased Cancer Fatigue Scale (CFS) was associated with both docosahexaenoic acid (DHA) (p = 0.06) and omega-3 index (p = 0.08) at baseline in all participants (n = 46, omega-6/omega-3 ratio = 6.79, SD = 1.90). On the contrary, DHA at baseline was positively correlated with change in CRF (r = 0.40, p = 0.06) in the control group (n = 24, omega-6/omega-3 ratio = 7.0). Moreover, eicosapentaenoic acid (EPA) at baseline was positively correlated with leg strength (r = 0.39, p = 0.10) in the exercise group. In conclusion, blood PUFA balance might be associated with the effect of exercise on CRF. In addition, higher EPA in individuals who conducted exercise likely has a beneficial effect on muscle strength. Further investigation is needed to clarify the interaction between PUFAs and exercise for alleviating CRF.

Beneficial effects of a plant-fish oil, slow carbohydrate diet on cardio-metabolic health exceed the correcting effects of metformin-pioglitazone in diabetic pigs fed a fast-food diet

Background

Lifestyle influences endocrine, metabolic and cardiovascular homeostasis. This study investigated the impact of diet and oral anti-diabetic medication on cardio-metabolic health in human-sized diabetic pigs.

Methods

After a growing pre-phase from ~30 to ~69 kg during which domestic pigs were fed either a low fat, low sucrose diet (group A) or a fast food-type diet elevated in lard (15%) and sucrose (40%) (group B), the pigs were subdivided in 5 groups (n = 7–8 pigs per group). Group 1, normal pigs from group A on a low fat, low sugar (L) pig diet and group 2, normal pigs from group B on a high lard (25%), sucrose-fructose (40%), cholesterol (1%) fast food-type (F) diet. Diabetes (D) was induced in group B pigs by streptozotocin and group 3 received the F diet (DF), group 4 received the F diet with Anti-diabetic medication metformin (2 g.day^-1)-pioglitazone (40 mg.day^-1) (DFA) and group 5 switched to a Plant-Fish oil (25%), Slowly digestible starch (40%) diet (DPFS). The F and PFS diets were identical for fat, carbohydrate and protein content but only differed in fat and carbohydrate composition. The 5 pig groups were followed up for 7 weeks until reaching ~120 kg.

Results

In normal pigs, the F diet predisposed to several abnormalities related to metabolic syndrome. Diabetes amplified the inflammatory and cardiometabolic abnormalities of the F diet, but both oral FA medication and the PFS diet partially corrected these abnormalities (mean±SEM) as follows: Fasting plasma TNF-ɑ (pg.ml^-1) and NEFA (mmol.l^-1) concentrations were high (p<0.02) in DF (193±55 and 0.79±0.16), intermediate in DFA (136±40 and 0.57±012) and low in DPFS pigs (107±31 and 0.48±0.19). Meal intolerance (response over fasting) for glucose and triglycerides (area under the curve, mmol.h^-1) and for lactate (3-h postprandial, mmol.l^-1) was high (p<0.03) in DF (489±131, 8.6±4.8 and 2.2±0.6), intermediate in DFA (276±145, 1.4±1.1 and 1.6±0.4) and low in DPFS (184±62, 0.7±1.8 and 0.1±0.1). Insulin-mediated glucose disposal (mg.kg^-1.min^-1) showed a numerical trend (p = NS): low in DF (6.9±2.2), intermediate in DFA (8.2±1.3) and high in DPFS pigs (10.4±2.7). Liver weight (g.kg^-1 body weight) and liver triglyceride concentration (g.kg^-1 liver) were high (p<0.001) in DF (23.8±2.0 and 69±14), intermediate in DFA (21.1±2.0 and 49±15) and low in DPFS pigs (16.4±0.7 and 13±2.0). Aorta fatty streaks were high (p<0.01) in DF (16.4±5.7%), intermediate in DFA (7.4±4.5%) and low in DPFS pigs (0.05±0.02%).

Conclusion

This translational study using pigs with induced type 2 diabetes provides evidence that a change in nutritional life style from fast food to a plant-fish oil, slowly digestible starch diet can be more effective than sole anti-diabetic medication.

COpenhagen Neuroplastic TRaining Against Contractures in Toddlers (CONTRACT): protocol of an open-label randomised clinical trial with blinded assessment for prevention of contractures in infants with high risk of cerebral palsy

INTRODUCTION

Contractures are frequent causes of reduced mobility in children with cerebral palsy (CP) already at the age of 2-3 years. Reduced muscle use and muscle growth have been suggested as key factors in the development of contractures, suggesting that effective early prevention may have to involve stimuli that can facilitate muscle growth before the age of 1 year. The present study protocol was developed to assess the effectiveness of an early multicomponent intervention, CONTRACT, involving family-oriented and supervised home-based training, diet and electrical muscle stimulation directed at facilitating muscle growth and thus reduce the risk of contractures in children at high risk of CP compared with standard care.

METHODS AND ANALYSIS

A two-group, parallel, open-label randomised clinical trial with blinded assessment (n=50) will be conducted. Infants diagnosed with CP or designated at high risk of CP based on abnormal neuroimaging or absent fidgety movement determined as part of General Movement Assessment, age 9-17 weeks corrected age (CA) will be recruited. A balanced 1:1 randomisation will be made by a computer. The intervention will last for 6 months aiming to support parents in providing daily individualised, goal-directed activities and primarily in lower legs that may stimulate their child to move more and increase muscle growth. Guidance and education of the parents regarding the nutritional benefits of docosahexaenic acid (DHA) and vitamin D for the developing brain and muscle growth will be provided. Infants will receive DHA drops as nutritional supplements and neuromuscular stimulation to facilitate muscle growth. The control group will receive standard care as offered by their local hospital or community. Outcome measures will be taken at 9, 12, 18, 24, 36 and 48 months CA. Primary and secondary outcome measure will be lower leg muscle volume and stiffness of the triceps surae musculotendinous unit together with infant motor profile, respectively.

ETHICS AND DISSEMINATION

Full approval from the local ethics committee, Danish Committee System on Health Research Ethics, Region H (H-19041562). Experimental procedures conform with the Declaration of Helsinki.

TRIAL REGISTRATION NUMBER

NCT04250454.

EXPECTED RECRUITMENT PERIOD

1 January 2021-1 January 2025.

N-3 PUFA as an ergogenic supplement modulating muscle hypertrophy and strength: a systematic review

There is growing evidence that suggests that n-3 polyunsaturated fatty acids (PUFA) may improve physical performance when combined with proper training through modulation of muscle hypertrophy, muscle strength, and delayed onset muscle soreness (DOMS). This systematic review aims to examine the effect and optimal dosage of n-3 PUFA supplementation on muscle hypertrophy, muscle strength, and DOMS when combined with physical exercise. The PubMed, Web of Science, MEDLINE Complete, CINAHL and SPORTDiscus databases were searched following the PRISMA guidelines. Randomized controlled trials performed with healthy humans were considered. Fifteen studies with a total of 461 individuals were included in this systematic review. All of them measured muscle function (short physical performance test, range of motion (ROM), electromechanical delay (EMD), muscle echo intensity or muscle quality) and DOMS. Fourteen studies evaluated muscle strength and only six assessed muscle hypertrophy. Our results demonstrated that n-3 PUFA does not improve muscle hypertrophy, muscle strength or skeletal muscle biomarkers of inflammation and muscle damage beyond the benefits obtained by the training itself. Nevertheless, n-3 PUFA improves DOMS recovery and muscle function (measured by ROM, EMD and muscle quality).

Macronutrient balance and micronutrient amounts through growth and development

Nutrition is essential for human growth, particularly in newborns and children. An optimal growth needs a correct diet, in order to ensure an adequate intake of macronutrients and micronutrients. Macronutrients are the compounds that humans consume in largest quantities, mainly classified in carbohydrates, proteins and fats. Micronutrients are instead introduced in small quantities, but they are required for an adequate growth in the pediatric age, especially zinc, iron, vitamin D and folic acid. In this manuscript we describe the most important macro and micronutrients for children's growth.

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.

Endogenous conversion of n-6 to n-3 polyunsaturated fatty acids facilitates the repair of cardiotoxin-induced skeletal muscle injury in fat-1 mice

In this study, we investigated the beneficial effects of high endogenous levels of n-3 polyunsaturated fatty acids (PUFAs) on skeletal muscle repair and regeneration using a mouse cardiotoxin (CTX, 20 μM/200 μL) -induced gastrocnemius muscle injury model. Transgenic fat-1 mice expressing the Caenorhabditis elegans fat-1 gene, encoding n-3 fatty acid desaturase, showed higher n-3 PUFA levels and lower n-6/n-3 PUFA ratios in gastrocnemius muscle tissues. Hematoxylin and eosin and Masson’s trichrome staining of gastrocnemius sections revealed increased muscle fiber size and reduced fibrosis in fat-1 mice on days 7 and 14 after CTX injections. Gastrocnemius muscle tissues from fat-1 mice showed reduced inflammatory responses and increased muscle fiber regeneration reflecting enhanced activation of satellite cells on day 3 after cardiotoxin injections. Gastrocnemius muscle tissues from cardiotoxin-treated fat-1 mice showed reduced levels of pro-apoptotic proteins (Caspase 3 and Bax) and increased levels of anti-apoptotic proteins (Bcl-2 and Survivin). Moreover, eicosapentaenoic acid (EPA) reduced the incidence of apoptosis among cardiotoxin-treated C2C12 mouse myoblasts. These findings demonstrate that higher endogenous n-3 PUFA levels in fat-1 mice enhances skeletal muscle repair and regeneration following cardiotoxin-induced injury.

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.

Molecular Mechanisms and Treatment of Sarcopenia in Liver Disease: A Review of Current Knowledge

Sarcopenia is characterized by progressive and generalized loss of skeletal muscle mass and strength that occurs with aging or in association with various diseases. The condition is prevalent worldwide and occurs more frequently in patients with chronic diseases owing to the intrinsic relationship of muscles with glucose, lipid, and protein metabolism. Liver cirrhosis is characterized by the progression of necro-inflammatory liver diseases, which leads to fibrosis, portal hypertension, and a catabolic state, which causes loss of muscle tissue. Sarcopenia is of significant concern in the state of liver cirrhosis because sarcopenia has been associated with higher mortality, increased hospital admissions, worse post-liver transplant outcomes, decreased quality of life, and increased risk for other complications associated with cirrhosis. Therefore, sarcopenia is also an important feature of liver cirrhosis, representing a negative prognostic factor and influencing mortality. An increased understanding of sarcopenia could lead to the development of novel therapeutic approaches that could help improve the cognitive impairment of cirrhotic patients; therefore, we present a review of the mechanisms and diagnosis of sarcopenia in liver disease and existing therapeutic approaches.

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.

Muscle Injury in Bodybuilding Based on Mesoporous Multifunctional Nanomaterials for Sports Rehabilitation Training

As an important means of treating diseases, chemical-based drugs have always guaranteed people’s health and longevity. However, due to the nature of some drugs, their use in the medical field is limited. This study mainly discusses the treatment of muscle damage based on sports rehabilitation training mesoporous multifunctional nanomaterials in bodybuilding. The biological characteristics of the targeted control of mesoporous multifunctional nanomaterials for target drugs were studied by analyzing the regeneration of skeletal muscles of mice after gastrocnemius strain under computer control. The electrostatic interactions modified by the consensus binding between AS1411 and Dimer-PPTcDA on the surface of mesoporous silicon are used to block the pores, and the release of objective molecules depends on the concentration of the drug in the tendon cells and the time of action. In this system, AS1411 has both the characteristics of the target substance and the active site of the targeted stimulus response in the cell. After FAM is labeled AS1411, the fluorescence of FAM can be used to monitor the release of the drug in real time, so as to directly release the drug to the lesion, maintain local effectiveness, and greatly improve the biological activity of the drug. In addition, in the safety analysis of mesoporous multifunctional nanomaterials on cells, if the concentration of nanoparticles is 90 μg/mL, the cell survival rate is almost 100%. The results show that the mesoporous multifunctional nanomaterials have low cytotoxicity and cell activity is not affected. The smaller the particle size of mesoporous silicon, the easier it is to invade the focus cells. In addition, confocal microscopy imaging has also effectively demonstrated the targeting effect of mesoporous multifunctional nanomaterials on cells.

The regulatory role of dietary factors in skeletal muscle development, regeneration and function

Skeletal muscle plays a crucial role in motor function, respiration, and whole-body energy homeostasis. How to regulate the development and function of skeletal muscle has become a hot research topic for improving lifestyle and extending life span. Numerous transcription factors and nutritional factors have been clarified are closely associated with the regulation of skeletal muscle development, regeneration and function. In this article, the roles of different dietary factors including green tea, quercetin, curcumin (CUR), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and resveratrol (RES) in regulating skeletal muscle development, muscle mass, muscle function, and muscle recovery have been summarized and discussed. We also reviewed the potential regulatory molecular mechanism of these factors. Based on the current findings, dietary factors may be used as a potential therapeutic agent to treat skeletal muscle dysfunction as well as its related diseases.

Nutritional interventions for reducing the signs and symptoms of exercise-induced muscle damage and accelerate recovery in athletes: current knowledge, practical application and future perspectives

PURPOSE

This review provides an overview of the current knowledge of the nutritional strategies to treat the signs and symptoms related to EIMD. These strategies have been organized into the following sections based upon the quality and quantity of the scientific support available: (1) interventions with a good level of evidence; (2) interventions with some evidence and require more research; and (3) potential nutritional interventions with little to-no-evidence to support efficacy.

METHOD

Pubmed, EMBASE, Scopus and Web of Science were used. The search terms 'EIMD' and 'exercise-induced muscle damage' were individually concatenated with 'supplementation', 'athletes', 'recovery', 'adaptation', 'nutritional strategies', hormesis'.

RESULT

Supplementation with tart cherries, beetroot, pomegranate, creatine monohydrate and vitamin D appear to provide a prophylactic effect in reducing EIMD. β-hydroxy β-methylbutyrate, and the ingestion of protein, BCAA and milk could represent promising strategies to manage EIMD. Other nutritional interventions were identified but offered limited effect in the treatment of EIMD; however, inconsistencies in the dose and frequency of interventions might account for the lack of consensus regarding their efficacy.

CONCLUSION

There are clearly varying levels of evidence and practitioners should be mindful to refer to this evidence-base when prescribing to clients and athletes. One concern is the potential for these interventions to interfere with the exercise-recovery-adaptation continuum. Whilst there is no evidence that these interventions will blunt adaptation, it seems pragmatic to use a periodised approach to administering these strategies until data are in place to provide and evidence base on any interference effect on adaptation.

Improvement in serum lipids and liver morphology after supplementation of the diet with fish oil is more evident under regular feeding conditions than under high-fat or mixed diets in rats

BACKGROUND

Dietary n- 3 polyunsaturated fatty acids (PUFAs) have a role in preventing cardiovascular and hepatic diseases. However, their effects might differ significantly depending on individual dietary patterns. The aim of the present study was to evaluate the effects of dietary supplementation with ω-3 fatty acids (FA), administered in different schedules, on hepatic and aortic histological structure, lipid profile, and body weight (BW) in male Wistar rats under standard (SD), high-fat diet (HFD) and mixed feeding conditions.

METHODS

PUFA treatment consisted of the administration of 50 mg/kg fish oil (FO) daily by oral gavage. HFD was obtained by adding a suspension of 4% cholesterol, thiouracil and cholic acid to the animals' drinking water. The rats were maintained on the diets for 6 weeks, and different schedules of PUFA administration were used. At 14, 28, and 42 days, the morphology of liver and aortic samples and the levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), and triglycerides (TG) were assessed.

RESULTS

The HFD groups exhibited significant hyperlipidemia and aortic inflammation, with progression to atherogenesis after 6 weeks. Administration of PUFAs slightly attenuated the aortic changes in these groups and reduced the liver's tendency to steatosis. FO-induced metabolic improvement was more evident in SD than in HFD rats. For instance, after the first 2 weeks, SD animals that received PUFAs had significantly increased HDL levels vs. controls (62.375 ± 4.10 vs. 52.625 ± 8.38 mg/dL, P < 0.05), but HFD rats did not, and decreased TG levels were observed exclusively in the SD rats (57.6 ± 4.09 vs. 66 ± 4.69 mg/dL, P < 0.05). After 6 weeks of n- 3 PUFA administration, LDL was significantly lower in the SD rats than in controls (13.67 ± 4.13 vs. 30.83 ± 2.86 mg/dL, P < 0.001), but the decrease in the HFD rats, although significant (49.17 ± 5.85 mg/dL vs. 57.17 ± 4.96 g/dL, P < 0.05), was not as marked. In the mixed-diet groups, administration of 50 mg/kg/day FO for 14 days under SD conditions following 4 weeks of HFD slightly decreased TG (86.625 ± 11.67 vs. 73 ± 4.52 mg/dL, P < 0.05) and increased HDL (45.875 ± 5.28 vs. 56 ± 3.16 mg/dL). However, in these animals, n-3 PUFA administration had no effect on LDL or TC. Administration of half of the above dose failed to improve any biochemical parameters. FO protected against excessive weight gain mainly under SD conditions.

CONCLUSIONS

The results show that FO confers more protection against cardiovascular risk factors (increased LDL and TG, decreased HDL) and liver lipid accumulation when given to rats consuming regular diets than when given to rats consuming a high-fat diet. This argues that priority should be given to consumption of a healthy diet rather than to the use of supplements. The effectiveness of n-3 PUFAs might be reduced in the case of hyperlipidic intake or after consumption of a high-fat diet.

The effect of fish oil supplementation on the promotion and preservation of lean body mass, strength, and recovery from physiological stress in young, healthy adults: a systematic review

Context

Military personnel are subjected to physiologically stressful environments during combat and its associated training. Evidence suggests that fish oil–derived n-3 polyunsaturated fatty acids (FO n-3 PUFAs) may affect military personnel’s performance by promoting or preserving lean body mass, strength, and power, while enhancing recovery from training-associated muscle damage.

Objective

Following PRISMA guidelines, this systematic review assessed the evidence for FO n-3 PUFA supplementation across various military-relevant outcomes related to physical performance in healthy adult populations.

Data Sources

The PubMed, Embase, and the CINAHL databases were searched along with references lists of selected articles and reviews.

Data Extraction

Eighteen trials were assessed for bias, and descriptive data were extracted.

Data Analysis

Of the 18 studies included, 12 trials favored FO n-3 PUFA supplementation in ≥ 1 of the performance outcomes.

Conclusion

Overall, FO n-3 PUFA supplementation likely preserves strength and very likely enhances recovery from physiological stress in young, healthy adults. However, FO n-3 PUFAs’ role in promoting or preserving lean body mass or promoting strength is unclear and warrants additional investigation.

Systematic Review Registration

PROSPERO registration no. CRD42020152786.

Omega-3 index in 2018/19

The omega-3 index, the percentage of EPA plus DHA in erythrocytes (measured by standardised analysis), represents a human body's status in EPA and DHA. An omega-3 index is measured in many laboratories around the world; however, even small differences in analytical methods entail large differences in results. Nevertheless, results are frequently related to the target range of 8-11 %, defined for the original and scientifically validated method (HS-Omega-3 Index®), raising ethical issues, and calling for standardisation. No human subject has an omega-3 index <2 %, indicating a vital minimum. Thus, the absence of EPA and DHA cannot be tested against presence. Moreover, clinical events correlate with levels, less with the dose of EPA and DHA, and the bioavailability of EPA and DHA varies inter-individually. Therefore, the effects of EPA and DHA are difficult to demonstrate using typical drug trial methods. Recent epidemiologic data further support the relevance of the omega-3 index in the cardiovascular field, since total mortality, cardiovascular mortality, cardiovascular events such as myocardial infarction or stroke, or blood pressure all correlate inversely with the omega-3 index. The omega-3 index directly correlates with complex brain functions. Compiling recent data supports the target range for the omega-3 index of 8-11 % in pregnancy. Many other potential applications have emerged. Some, but not all health issues mentioned have already been demonstrated to be improved by increasing intake of EPA and DHA. Increasing the omega-3 index into the target range of 8-11 % with individualised doses of toxin-free sources for EPA and DHA is tolerable and safe.

Dietary and Biological Assessment of the Omega-3 Status of Collegiate Athletes: A Cross-Sectional Analysis

Omega-3 fatty acids (ω-3 FA) are associated with cardiovascular health, brain function, reduction of inflammation, and several other physiological roles of importance to competitive athletes. The ω-3 FA status of National Collegiate Athletic Association (NCAA) Division I athletes has not been well-described. The purpose of this study was to evaluate the ω-3 FA status of NCAA Division I athletes using dietary and biological assessment methodology. Athletes from nine NCAA Division I institutions from throughout the U.S. (n = 1,528, 51% male, 34 sports represented, 19.9 ± 1.4 years of age) completed a food frequency questionnaire (FFQ) to assess ω-3 FA from diet and supplements. Omega-3 Index (O3i) was evaluated in a sub-set of these participants (n = 298, 55% male, 21 sports represented, 20.0 ± 1.3 years of age) using dried blood spot sampling. Only 6% (n = 93) of athletes achieved the Academy of Nutrition & Dietetics’ recommendation to consume 500 mg DHA+EPA per day. Use of ω-3 FA supplements was reported by 15% (n = 229) of participants. O3i was 4.33 ± 0.81%, with no participants meeting the O3i benchmark of 8% associated with the lowest risk of cardiovascular disease. Every additional weekly serving of fish or seafood was associated with an absolute O3i increase of 0.27%. Overall, sub-optimal ω-3 FA status was observed among a large, geographically diverse group of male and female NCAA Division I athletes. These findings may inform interventions aimed at improving ω-3 FA status of collegiate athletes. Further research on athlete-specific ω-3 FA requirements is needed.

Supplementation of Re-Esterified Docosahexaenoic and Eicosapentaenoic Acids Reduce Inflammatory and Muscle Damage Markers after Exercise in Endurance Athletes: A Randomized, Controlled Crossover Trial

This study aimed to analyse the effect of 10 weeks of a highly concentrated docosahexaenoic acid (DHA) + eicosapentaenoic (EPA) supplementation (ratio 8:1) on strength deficit and inflammatory and muscle damage markers in athletes. Fifteen endurance athletes participated in the study. In a randomized, double-blinded cross-over controlled design, the athletes were supplemented with a re-esterified triglyceride containing 2.1 g/day of DHA + 240 mg/day of EPA or placebo for 10 weeks. After a 4-week wash out period, participants were supplemented with the opposite treatment. Before and after each supplementation period, participants performed one eccentric-induced muscle damage exercise training session (ECC). Before, post-exercise min and 24 and 48 h after exercise, muscle soreness, knee isokinetic strength and muscle damage and inflammatory markers were tested. No significant differences in strength deficit variables were found between the two conditions in any of the testing sessions. However, a significant effect was observed in IL1β (p= 0.011) and IL6 (p= 0.009), which showed significantly lower values after DHA consumption than after placebo ingestion. Moreover, a significant main effect was observed in CPK (p = 0.014) and LDH-5 (p = 0.05), in which significantly lower values were found after DHA + EPA consumption. In addition, there was a significant effect on muscle soreness (p = 0.049), lower values being obtained after DHA + EPA consumption. Ten weeks of re-esterified DHA + EPA promoted lower concentrations of inflammation and muscle damage markers and decreased muscle soreness but did not improve the strength deficit after an ECC in endurance athletes.

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.

Effects of long-term microalgae supplementation on muscle microstructure, meat quality and fatty acid composition in growing pigs

We investigated the effects of long-term microalgae supplementation (7% in a piglet diet and 5% in a fattening diet) on muscle microstructure and meat quality, including fatty acid composition in female Landrace pigs (n = 31). The major effects were muscle-specific increases in n-3 and n-6 polyunsaturated fatty acids (PUFA) concentrations, resulting in increased accumulation of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Carcass traits and meat quality of longissimus thoracis muscle were not affected by the microalgae diet with the exception of reduced drip loss (p = 0.01) and increased protein proportion (p = 0.04). In addition, the microalgae diet resulted in a shift to a more oxidative myofibre type composition in semitendinosus but not longissimus thoracis muscle. In conclusion, microalgae supplementation offers a unique opportunity to enhance essential n-3 PUFA contents in pig meat. The results support small but coordinated changes in skeletal muscle phenotypic appearance and functionality.