High Dose Omega-3 Fatty Acid Administration and Skeletal Muscle Protein Turnover in Maintenance Hemodialysis Patients

The effects of omega-3 polyunsaturated fatty acids on muscle and whole-body protein synthesis: a systematic review and meta-analysis

CONTEXT

Sarcopenia describes the age-related decline in skeletal muscle mass and strength that is driven, at least in part, by an imbalance between rates of muscle protein synthesis (MPS) and muscle protein breakdown. An expanding body of literature has examined the effect of omega-3 polyunsaturated fatty acid (n-3 PUFA) ingestion on MPS rates in older adults, with mixed findings.

OBJECTIVE

The aim of this systematic review and meta-analysis was to investigate the effectiveness of n-3 PUFA ingestion in stimulating rates of MPS and whole-body protein synthesis in healthy adults and clinical populations.

DATA SOURCES

Searches were conducted of the PubMed, Web of Science, Cochrane Library, and Scopus databases from inception until December 2022 for articles on randomized controlled trials comparing the effect of n-3 PUFA ingestion vs a control or placebo on rates of MPS and whole-body protein synthesis. The search yielded 302 studies, of which 8 were eligible for inclusion.

DATA EXTRACTION

The random effects inverse-variance model was used and standardized mean differences (SMDs) with 95%CIs were calculated to assess the pooled effect. Risk of bias was assessed by the Cochrane Risk-of-Bias 2 tool.

DATA ANALYSIS

The main analysis indicated no effect of n-3 PUFA supplementation on MPS rates (k = 6; SMD: 0.03; 95%CI, -0.35 to 0.40; I2 = 30%; P = .89). Subgroup analysis based on age, n-3 PUFA dose, duration of supplementation, and method used to measure fractional synthetic rate also revealed no effect of n-3 PUFA ingestion on MPS. In contrast, the main analysis demonstrated an effect of n-3 PUFA ingestion on increasing whole-body protein synthesis rates (k = 3; SMD: 0.51; 95%CI, 0.12-0.90; I2 = 0%; P = .01).

CONCLUSIONS

n-3 PUFA ingestion augments the stimulation of whole-body protein synthesis rates in healthy adults and clinical populations.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. 42022366986.

From genes to systems: The role of food supplementation in the regulation of sepsis-induced inflammation

Systemic inflammation includes a widespread immune response to a harmful stimulus that results in extensive systemic damage. One common example of systemic inflammation is sepsis, which is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Under the pro-inflammatory environment of sepsis, oxidative stress contributes to tissue damage due to dysfunctional microcirculation that progressively causes the failure of multiple organs that ultimately triggers death. To address the underlying inflammatory condition in critically ill patients, progress has been made to assess the beneficial effects of dietary supplements, which include polyphenols, amino acids, fatty acids, vitamins, and minerals that are recognized for their immuno-modulating, anticoagulating, and analgesic properties. Therefore, we aimed to review and discuss the contribution of food-derived supplementation in the regulation of inflammation from gene expression to physiological responses and summarize the precedented potential of current therapeutic approaches during systemic inflammation.

Protectin DX as a therapeutic strategy against frailty in mice

Frailty in aging is driven by the dysregulation of multiple biological pathways. Protectin DX (PDX) is a docosahexaenoic acid (DHA)-derived molecule that alleviates many chronic inflammatory disorders, but its potential effects on frailty remain unknown. Our goal is to identify age-related impairments in metabolic systems and to evaluate the therapeutic potential of PDX on frailty, physical performance, and health parameters. A set of 22-month-old C57BL/6 male and female mice were assigned to vehicle (Old) or PDX daily gavage treatment for 9 weeks, whereas 6-month-old (Adult) mice received only vehicle. Forelimb and hindlimb strength, endurance, voluntary wheel activity and walking speed determined physical performance and were combined with a frailty index score and body weight loss to determine frailty status. Our data shows that old vehicle-treated mice from both sexes had body weight loss paralleling visceromegaly, and Old females also had impaired insulin clearance as compared to the Adult group. Aging was associated with physical performance decline together with higher odds of frailty development. There was also age-driven mesangial expansion and glomerular hypertrophy as well as bone mineral density loss. All of the in vivo and in vitro impairments observed with aging co-occurred with upregulation of inflammatory pathways and Myc signaling as well as downregulation of genes related to adipogenesis and oxidative phosphorylation in liver. PDX attenuated the age-driven physical performance (strength, exhaustion, walking speed) decline, promoted robustness, prevented bone losses and partially reversed changes in hepatic expression of Myc targets and metabolic genes. In conclusion, our data provides evidence of the beneficial therapeutic effect of PDX against features of frailty in mice. Further studies are warranted to investigate the mechanisms of action and the potential for human translation.

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.

Effects of omega-3 supplementation on serum albumin, pre-albumin and the CRP/albumin ratio in hospitalized patients: a systematic review and meta-analysis

CONTEXT

Low serum albumin and pre-albumin concentrations are associated with edema, infection, thrombosis, heart failure, and mortality.

OBJECTIVE

This comprehensive systematic review and meta-analysis of clinical trials was conducted to summarize the available findings on the impact of omega-3 supplementation on albumin, pre-albumin, and the C-reactive protein/albumin ratio in hospitalized patients.

DATA SOURCES

PubMed, Web of Science, Scopus, and Google Scholar databases were searched from January 1990 to October 2021.

DATA EXTRACTION

Extracted data from 50 randomized controlled trials (RCTs) with a total number of 3196 participants were analyzed using the random-effects model. The dose-dependent effect was also evaluated.

DATA ANALYSIS

Oral omega-3 supplementation significantly increased serum albumin concentrations in patients with cancer (weighted mean difference [WMD]: 0.19; 95% CI: 0.05, 0.33, P= 0.006), patients on dialysis (WMD: 0.14; 95% CI: 0.01, 0.28, P= 0.042), and those with hypoalbuminemia (WMD: 0.38; 95% CI: 0.03, 0.72, P = 0.033); however, there was no significant effect among patients with gastrointestinal or hepatologic diseases. Moreover, each 1000 mg/day increase in oral omega-3 supplementation resulted in elevated serum albumin levels in cancer patients (WMD: 0.15; 95% CI: 0.07, 0.24, P < 0.001). In addition, a favorable effect of oral omega-3 supplementation on pre-albumin levels was observed among patients with cancer (WMD: 33.87; 95% CI: 12.34, 55.39, P = 0.002). A similar significant effect of parenteral omega-3 supplementation on pre-albumin concentrations was seen among those with gastrointestinal and hepatologic diseases as well (WMD: 23.30; 95% CI: 13.58, 33.03, P < 0.001). No significant effect of oral omega-3 supplementation on the CRP/albumin ratio was found.

CONCLUSIONS

Overall, omega-3 fatty acids supplementation resulted in a favorable change in serum albumin and pre-albumin concentrations in hospitalized patients.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021285704.

N-3 Fatty Acid Supplementation Impacts Protein Metabolism Faster Than it Lowers Proinflammatory Cytokines in Advanced Breast Cancer Patients: Natural 15N/14N Variations during a Clinical Trial

While clinical evidence remains limited, an extensive amount of research suggests a beneficial role of n-3 polyunsaturated fatty acid supplementation in cancer treatment. One potential benefit is an improvement of protein homeostasis, but how protein metabolism depends on proinflammatory cytokines in this context remains unclear. Here, using the natural abundance of the stable isotopes of nitrogen as a marker of changes in protein metabolism during a randomized, double-blind, controlled clinical trial, we show that protein homeostasis is affected way faster than proinflammatory cytokines in metastatic breast cancer patients supplemented with n-3 polyunsaturated fatty acids. We provide some evidence that this response is unrelated to major changes in whole-body substrate oxidation. In addition, we demonstrate that more fatty acids were impacted by metabolic regulations than by differences in their intake levels during the supplementation. This study documents that the percentage of patients that complied with the supplementation decreased with time, making compliance assessment crucial for the kinetic analysis of the metabolic and inflammatory responses. Our results highlight the time-dependent nature of metabolic and inflammatory changes during long-chain n-3 fatty acid supplementation.

Pathophysiological mechanisms leading to muscle loss in chronic kidney disease

Loss of muscle proteins is a deleterious consequence of chronic kidney disease (CKD) that causes a decrease in muscle strength and function, and can lead to a reduction in quality of life and increased risk of morbidity and mortality. The effectiveness of current treatment strategies in preventing or reversing muscle protein losses is limited. The limitations largely stem from the systemic nature of diseases such as CKD, which stimulate skeletal muscle protein degradation pathways while simultaneously activating mechanisms that impair muscle protein synthesis and repair. Stimuli that initiate muscle protein loss include metabolic acidosis, insulin and IGF1 resistance, changes in hormones, cytokines, inflammatory processes and decreased appetite. A growing body of evidence suggests that signalling molecules secreted from muscle can enter the circulation and subsequently interact with recipient organs, including the kidneys, while conversely, pathological events in the kidney can adversely influence protein metabolism in skeletal muscle, demonstrating the existence of crosstalk between kidney and muscle. Together, these signals, whether direct or indirect, induce changes in the levels of regulatory and effector proteins via alterations in mRNAs, microRNAs and chromatin epigenetic responses. Advances in our understanding of the signals and processes that mediate muscle loss in CKD and other muscle wasting conditions will support the future development of therapeutic strategies to reduce muscle loss.

The effect of long chain omega-3 polyunsaturated fatty acids on muscle mass and function in sarcopenia: A scoping systematic review and meta-analysis

BACKGROUND & AIMS

Sarcopenia is characterized by the progressive loss of skeletal muscle mass and function, which reduces mobility and quality of life. Risk factors for sarcopenia include advanced age, physical inactivity, obesity, and chronic diseases such as cancer or rheumatoid arthritis. Omega-3 long chain polyunsaturated fatty acids (LC PUFAs) might be associated with a reduction in risk of sarcopenia due to their anti-inflammatory effects.

METHODS

We conducted a systematic review and meta-analysis to quantify the effects of omega-3 LC PUFAs on muscle mass, volume and function parameters. The National Library of Medicine's MEDLINE/PubMed database was searched on 9th October 2020 for randomized controlled trials that used omega-3 LC PUFAs as an intervention with muscle-related endpoints. A snowballing search to identify additional studies was completed on 23rd April 2021. The meta-analysis was conducted using meta-essentials worksheet 3. Bias was assessed using the Jadad scale.

RESULTS

123 studies were identified with the systematic searches. Most studies were performed in disease populations, such as cancer or chronic obstructive pulmonary disease (COPD), or in healthy individuals after a fatiguing exercise bout. The endpoints lean body mass, skeletal muscle mass, mid-arm muscle circumference, handgrip strength, quadriceps maximal voluntary capacity (MVC), and 1-repetition maximum chest press were selected for meta-analysis based on the number of available studies; thus 66 studies were included in the quantitative synthesis. Using a random effects model and 2-tailed p-value, there was a significant relationship in favor of omega-3 LC PUFA supplementation for lean body mass (effect size 0.27, 95%CI 0.04 to 0.51), skeletal muscle mass (effect size 0.31, 95%CI 0.01 to 0.60) and quadriceps MVC (effect size 0.47, 95%CI 0.02 to 0.93).

CONCLUSION

The results indicate that there is a positive effect of omega-3 LC PUFA supplementation on overall body muscle mass and strength. Small study size and heterogeneity limit the applicability of these findings for sarcopenia prevention. Larger trials in populations at risk of sarcopenia would strengthen the evidence base.

Effects of Omega-3 Fatty Acid Intake in Patients Undergoing Dialysis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective: Fish oil supplementation has been shown to be beneficial for hemodialysis (HD) patients. The aim of this study was to evaluate the efficacy and safety of omega-3 fatty acid supplementation or dietary adjustment in dialysis patients.Methods: A systematic literature search was performed to identify relevant randomized controlled trials (RCTs) to study the effects of omega-3 supplementation on dialysis patients. The variables of interest included the levels of blood lipids, inflammatory indicators, proteins, parathyroid hormone (PTH), gastrointestinal adverse reactions, and all-cause mortality. The mean differences (MDs) and 95% confidence intervals (CIs) were calculated, and heterogeneity was assessed with the I² test. Subgroup and sensitivity analyses were performed to identify potential sources.Results: The systematic review included 49 RCTs and evaluated the efficacy and safety of omega-3 fatty acid supplementation in dialysis patients. Data synthesis showed that compared with the control group, the group receivingomega-3 supplementation exhibited significantly decreased serum triglyceride (TG) levels, decreased C-reactive protein (CRP) and TNF-alpha levels, increased hemoglobin levels, reduced serum phosphorus levels, increased PTH levels, and increased gastrointestinal adverse reactions to a certain extent. Furthermore, there was no effect on the blood total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), albumin or calcium levels and all-cause mortality.Conclusion: Omega-3 fatty acid supplementation is related to a reduction in serum TG, LDL and inflammation index levels and has few adverse reactions. Therefore, omega-3 fatty acid supplementation may be a useful nutrition therapy for dialysis patients.

Renal Rehabilitation: Exercise Intervention and Nutritional Support in Dialysis Patients

With the growing number of dialysis patients with frailty, the concept of renal rehabilitation, including exercise intervention and nutrition programs for patients with chronic kidney disease (CKD), has become popular recently. Renal rehabilitation is a comprehensive multidisciplinary program for CKD patients that is led by doctors, rehabilitation therapists, diet nutritionists, nursing specialists, social workers, pharmacists, and therapists. Many observational studies have observed better outcomes in CKD patients with more physical activity. Furthermore, recent systematic reviews have shown the beneficial effects of exercise intervention on exercise tolerance, physical ability, and quality of life in dialysis patients, though the beneficial effect on overall mortality remains unclear. Nutritional support is also fundamental to renal rehabilitation. There are various causes of skeletal muscle loss in CKD patients. To prevent muscle protein catabolism, in addition to exercise, a sufficient supply of energy, including carbohydrates, protein, iron, and vitamins, is needed. Because of decreased digestive function and energy loss due to dialysis treatment, dialysis patients are recommended to ingest 1.2-fold more protein than the regular population. Motivating patients to join in activities is also an important part of renal rehabilitation. It is essential for us to recognize the importance of renal rehabilitation to maximize patient satisfaction.

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.

How to Overcome Anabolic Resistance in Dialysis-Treated Patients?

A current hypothesis is that dialysis-treated patients are "anabolic resistant" i. e., their muscle protein synthesis (MPS) response to anabolic stimuli is blunted, an effect which leads to muscle wasting and poor physical performance in aging and in several chronic diseases. The importance of maintaining muscle mass and MPS is often neglected in dialysis-treated patients; better than to describe mechanisms leading to energy-protein wasting, the aim of this narrative review is to suggest possible strategies to overcome anabolic resistance in this patient's category. Food intake, in particular dietary protein, and physical activity, are the two major anabolic stimuli. Unfortunately, dialysis patients are often aged and have a sedentary behavior, all conditions which per se may induce a state of "anabolic resistance." In addition, patients on dialysis are exposed to amino acid or protein deprivation during the dialysis sessions. Unfortunately, the optimal amount and formula of protein/amino acid composition in supplements to maximixe MPS is still unknown in dialysis patients. In young healthy subjects, 20 g whey protein maximally stimulate MPS. However, recent observations suggest that dialysis patients need greater amounts of proteins than healthy subjects to maximally stimulate MPS. Since unneccesary amounts of amino acids could stimulate ureagenesis, toxins and acid production, it is urgent to obtain information on the optimal dose of proteins or amino acids/ketoacids to maximize MPS in this patients' population. In the meantime, the issue of maintaining muscle mass and function in dialysis-treated CKD patients needs not to be overlooked by the kidney community.

Efficacy of Polyunsaturated Fatty Acids on Inflammatory Markers in Patients Undergoing Dialysis: A Systematic Review with Network Meta-Analysis of Randomized Clinical Trials

The effects of polyunsaturated fatty acids (PUFAs) on inflammatory markers among patients receiving dialysis have been discussed for a long time, but previous syntheses made controversial conclusion because of highly conceptual heterogeneity in their synthesis. Thus, to further understanding of this topic, we comprehensively gathered relevant randomized clinical trials (RCTs) before April 2019, and two authors independently extracted data of C-reactive protein (CRP), high-sensitivity C-reactive protein (hs-CRP), and interleukin-6 (IL-6) for conducting network meta-analysis. Eighteen eligible RCTs with 962 patients undergoing dialysis were included in our study. The result showed that with placebo as the reference, PUFAs was the only treatment showing significantly lower CRP (weighted mean difference (WMD): −0.37, 95% confidence interval (CI): −0.07 to −0.68), but the CRP in PUFAs group was not significantly lower than vitamin E, PUFAs plus vitamin E, or medium-chain triglyceride. Although no significant changes were noted for hs-CRP and IL-6 levels, PUFAs showed the best ranking among treatments according to surface under the cumulative ranking. Therefore, PUFAs could be a protective option for patients receiving dialysis in clinical practice.

Dietary fatty acid intake in hemodialysis patients and associations with circulating fatty acid profiles: A cross-sectional study

OBJECTIVES

The aims of this study were threefold: first, to assess the dietary fatty acid (FA) intake and blood FA status in Malaysian patients on hemodialysis (HD); second, to examine the association between dietary FA intakes and blood FA profiles in patients on HD; and third, to determine whether blood FAs could serve as a biomarker of dietary fat intake quality in these patients.

METHODS

Using 3 d of dietary records, FA intakes of 333 recruited patients were calculated using a food database built from laboratory analyses of commonly consumed Malaysian foods. Plasma triacylglycerol (TG) and erythrocyte FAs were determined by gas chromatography.

RESULTS

High dietary saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) consumption trends were observed. Patients on HD also reported low dietary ω-3 and ω-6 polyunsaturated fatty acid (PUFA) consumptions and low levels of TG and erythrocyte FAs. TG and dietary FAs were significantly associated respective to total PUFA, total ω-6 PUFA, 18:2 ω-6, total ω-3 PUFA, 18:3 ω-3, 22:6 ω-3, and trans 18:2 isomers (P < 0.05). Contrarily, only dietary total ω-3 PUFA and 22:6 ω-3 were significantly associated with erythrocyte FAs (P < 0.01). The highest tertile of fish and shellfish consumption reflected a significantly higher proportion of TG 22:6 ω-3. Dietary SFAs were directly associated with TG and erythrocyte MUFA, whereas dietary PUFAs were not.

CONCLUSION

TG and erythrocyte FAs serve as biomarkers of dietary PUFA intake in patients on HD. Elevation of circulating MUFA may be attributed to inadequate intake of PUFAs.

Omega-3 fatty acids for dialysis vascular access outcomes in patients with chronic kidney disease

BACKGROUND

Maintaining long-term vascular access patency is necessary for high quality haemodialysis (HD) treatment of patients with the terminal and most serious stage of chronic kidney disease (CKD) - end-stage kidney disease (ESKD). Oral supplementation with omega-3 fatty acids (ω-3FA) may help to prevent blockage of the vascular access by reducing the risk of thrombosis and stenosis.

OBJECTIVES

To evaluate the efficacy and safety of ω-3FA supplementation versus placebo or no treatment for maintaining vascular access patency in ESKD patients undergoing HD.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 23 July 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of omega-3 fatty acids versus placebo that assessed the patency of arteriovenous fistula (AVF) or arteriovenous graft (AVG) types of vascular access in ESKD patients.

DATA COLLECTION AND ANALYSIS

We assessed the risk of bias of each eligible study using the Cochrane Risk of Bias tool and made separate overall risk of bias judgments for the efficacy and safety outcomes. The certainty of evidence was assessed using the GRADE approach. The primary efficacy outcome was loss of vascular patency and the primary safety outcomes were occurrences of serious adverse events (e.g. death, hospitalisation, cardiovascular events, major bleeding). Secondary outcomes were the occurrence of non-serious adverse events (e.g. minor bleeding, gastrointestinal events and other adverse events). Efficacy effects were reported as risk ratios (RR) and safety effects as risk differences (RD) with 95% confidence intervals (CI). Studies were pooled separately by type of vascular access using a random-effects model.

MAIN RESULTS

Five studies (833 participants) were included; one was a very small pilot study of 7 participants. All studies compared oral ω-3FA supplements against placebo. Four studies enrolled participants with arteriovenous grafts (AVGs), and the other had participants with arteriovenous fistulas (AVFs). The risk of bias for both efficacy and safety outcomes was unclear for all studies, due mainly to incomplete reporting for allocation concealment and incompleteness of study follow-up.In AVF patients, ω-3FA supplementation probably makes little or no difference to the 12-month risk of patency loss (1 study, 536 participants: RR 1.01, 95% CI 0.84 to 1.21; moderate certainty evidence), risk of death (1 study, 567 participants: RD 0.00, 95% CI -0.03 to 0.02; moderate certainty evidence) and risk of hospitalisation (1 study, 567 participants: RD 0.00, 95% CI -0.08 to 0.08; low certainty evidence). There was no information on cardiovascular events and major bleeding.In AVG patients, it is very uncertain whether ω-3FA supplementation reduces the risk of patency loss within 6 months (2 studies, 41 participants: RR 0.91, 95% CI 0.36 to 2.28; very low certainty evidence) or 12 months (2 studies, 220 participants: RR 0.59, 95% CI 0.27 to 1.31; very low certainty evidence). ω-3FA supplementation may make little or no difference to the risk of death within 6 to 12 months in AVG patients (4 studies, 261 participants: RD 0.01, 95% CI -0.05 to 0.07; low certainty evidence). It is very uncertain if ω-3FA supplementation increases the risk of hospitalisation (3 studies, 65 participants: RD 0.08, 95% CI -0.11 to 0.28; very low certainty evidence), changes the risk of cardiovascular events (4 studies, 261 participants: RD -0.02, 95% CI -0.11 to 0.07; very low certainty evidence), or increases the risk of major bleeding (3 studies, 65 participants: RD 0.08, 95% CI -0.11 to 0.28; very low certainty evidence) within 6 to 12 months in AVG patients. There may be an increase in the risk of mild gastrointestinal adverse reactions (3 studies, 65 participants: RD 0.25, 95% CI 0.07 to 0.43; low certainty evidence) such as a sensation of bloatedness, gas or a fishy aftertaste.

AUTHORS' CONCLUSIONS

In CKD patients with an AVF, there is moderate certainty that ω-3FA supplementation makes little or no difference to preventing patency loss; and in patients with an AVG, it is very uncertain that ω-3FA supplementation prevents patency loss within 12 months.

Effects of Omega-3 Fatty Acids on Markers of Inflammation in Patients With Chronic Kidney Disease: A Controversial Issue

Chronic kidney disease (CKD) is a global problem which contributes to a significant morbidity and mortality in China. Concomitant inflammatory state further boosts the mortality due to cardiovascular events in patients with CKD undergoing dialysis. There is a general notion that Omega-3 fatty acids including docosahexaenoic acids (DHA) and eicosapentaenoic (EPA) have certain health benefits perhaps via the regulation of inflammation. However, the anti-inflammatory effect of omega-3 fatty acids in patients with CKD is controversial. We analyzed the data of oral supplementation of omega-3 fatty acids in CKD patients by searching literature on database from inception to August 2016. The analysis included randomized controlled trials (RCTs) derived from multiple databases, and the effect of omega-3 fatty acids supplementation versus the control cohorts were compared. All of the data analysis was calculated by RevMan 5.2. A total of 12 RCTs involving 487 patients were included in the meta-analysis. Among them 254 patients received omega-3 fatty acids and 233 patients served as controls who received placebo. The meta-analysis revealed no statistical significance in serum levels of C-reactive protein (CRP) (SMD, -0.20; 95% CI, -0.44 to 0.05; P = 0.11), IL-6 (SMD, 0.00; 95% CI, -0.33 to 0.33; P = 0.99) and TNF-α (SMD, 0.14; 95% CI, -0.17 to 0.44; P = 0.38) between the omega-3 fatty acids supplementation group and control. This suggested that there is insufficient evidence to conclude the benefit of omega-3 fatty acids oral supplementation in reducing serum levels of CRP, IL-6 and TNF-α in patients with CKD.

Update on the Impact of Omega 3 Fatty Acids on Inflammation, Insulin Resistance and Sarcopenia: A Review

Elderly and patients affected by chronic diseases face a high risk of muscle loss and impaired physical function. Omega 3 fatty acids (FA) attenuate inflammation and age-associated muscle loss, prevent systemic insulin resistance and improve plasma lipids, potentially impacting on sarcopenia. This paper aims to review recent randomized clinical studies assessing the effects a chronic omega 3 FA supplementation on inflammatory and metabolic profile during conditions characterized by sarcopenia (aging, insulin resistance, type 2 diabetes, chronic renal failure). A comprehensive search of three online databases was performed to identify eligible trials published between 2012 and 2017. A total of 36 studies met inclusion criteria. Omega 3 FA yielded mixed results on plasma triglycerides in the elderly and no effects in renal patients. No changes in systemic insulin resistance were observed. Inflammation markers did not benefit from omega 3 FA in insulin resistant and in renal subjects while decreasing in obese and elderly. Muscle related parameters improved in elderly and in renal patients. In conclusion, in aging- and in chronic disease-associated sarcopenia omega 3 FA are promising independently of associated anabolic stimuli or of anti-inflammatory effects. The evidence for improved glucose metabolism in insulin resistant and in chronic inflammatory states is less solid.