Gender differences in the effect of fish oil on appetite, inflammation and nutritional status in haemodialysis patients

Effectiveness of fish oil in controlling inflammation in adult patients undergoing hemodialysis: A systematic review and meta-analysis

Objective

Hemodialysis patients with chronic kidney disease often exhibit inflammation characterized by elevated levels of C-reactive protein, Interleukin 6 and tumor necrosis factor-alpha, and they are shown to be associated with cardiovascular impairment and enhanced renal failure. This study aims to assess the impact of fish oil intake on inflammation indicators in adult hemodialysis patients.

Methods

From the inception to December 2023, the datasets Cochrane Central, Google Scholar, Science Direct, Embase, and Pubmed were examined. Two authors independently searched, selected, and screened the literature. The pooled results are represented by weighted mean difference (WMD) with 95% confidence intervals. To investigate the causes of heterogeneity, subgroup analysis was done. Sensitivity analysis was then used to evaluate the validity of the combined findings.

Results

Thirteen randomized control trials studies were included. The pooled results showed that fish oil supplementation caused a significant reduction of the C-reactive protein level (WMD, -2.92 mg/L; 95% Confidence interval, -5.23, to -0.61; p = 0.01; I 2 = 99%), especially in patients with baseline C-reactive protein ⩾5 mg/L (WMD, -4.39 mg/L; 95% Confidence interval, -5.93 to 2.85; p < 0.00001; I 2 = 33%). Subgroup analyses showed that C-reactive protein baseline level (C-reactive protein <5 mg/L) was the main source of heterogeneity. Fish oil intake may not reduce the level of Interleukin 6 (WMD, -2.26; 95% Confidence interval: -19.61 to 15.09; p = 0.80; I 2 = 93%), nor will it reduce the level of tumor necrosis factor-alpha (random model: WMD, -2.51; 95% Confidence interval: 6.08 to 1.06; p = 0.17; I 2 = 98%).

Conclusion

Hemodialysis patients, especially those with C-reactive protein > 5 mg/L, responded to fish oil supplementation to reduce their C-reactive protein level; however, Interleukin 6 and tumor necrosis factor-alpha levels did not appear to be affected.

The effects of omega-3 fatty acids supplementation on hemoglobin, hematocrit, and platelet levels of patients with ESRD condition undergoing dialysis

Background

Concomitant inflammation may boost the cardiovascular complications in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD). Omega-3 fatty acids may have certain health benefits in HD patients. The aim of this study was to investigate the effects of omega-3 fatty acids supplementation on hematocrit (HCT), hemoglobin (HB) level and platelet (PLT) counts of HD patients.

Methods

A randomized controlled trial was conducted on HD patients at a private dialysis center in Rasht, Iran. Three omega-3 fatty acid supplement capsules (3 g/d) were administered daily for two months to patients in the intervention group (n = 55). The control group (n = 60) were given three placebo capsules containing medium chain triglyceride (MCT) oil, similar to the supplemental dose of the intervention group at the same period. Three parameters of HCT, HB and PLT were measured at baseline and after the intervention.

Results

The PLT count decreased in the intervention group compared to the control group (173.38 ± 74.76 vs. 227.68 ± 86.58 103/mm3, F = 4.83, P = 0.03). No significant change was found on the levels of HCT and HB parameters between the two groups after the intervention.

Conclusion

Omega-3 supplementation in HD patients may decrease the risk of forming blood clots in the blood vessels. Further studies are warranted.

Effects of marine-derived n-3 PUFA supplementation on soluble adhesion molecules: A systematic review and dose-response meta-analysis of randomized controlled trials

Long-chain n-3 poly unsaturated fatty acids have anti-inflammatory effects but their effects on serum levels of adhesion molecules are inconsistent and contradictory. In this updated systematic review and meta-analysis, marine sources of omega-3 fatty acids were pooled up to determine the effects of omega-3 supplementation on adhesion molecules. PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (from inception to April 2023) were searched and all RCTs investigating the effects of marine sources of omega-3, on blood concentrations of adhesion molecules were included and a meta-analysis undertaken. Forty-two RCTs were included involving 3555 participants aged from 18 to 75 years. Meta-analysis of 38 arms from 30 RCTs reporting serum concentrations of vascular cell adhesion molecule-1 (VCAM-1) showed a significant reduction after omega-3 supplementation (WMD: -1.26, 95% CI: -1.88 to -0.64 ng/mL, P < 0.001). Meta-analysis of 40 arms from 30 RCTs reporting serum concentrations of intercellular adhesion molecule-1 (ICAM-1) revealed a reduction following omega-3 supplementation, although it was not significant (WMD: -1.76, 95%CI: -3.68 to 0.16 ng/mL, P = 0.07). Meta-analysis of 27 arms from 21 trials showed no effect on E-selectin (WMD: 0.01, 95%CI: -0.02 to 0.04 ng/mL, P = 0.62). Pooling 15 arms from 11 RCTs showed a marginally significant reducing effect on P-selectin concentrations (WMD: -2.67, 95%CI: -5.53 to 0.19 ng/mL, P = 0.06). A considerable decrease in VCAM concentration was observed after omega-3 supplementation in this meta-analysis with a trend to decreases in both ICAM and P-selectin levels, with effects that may be significant depending on study design, and there was no effect on E-selectin.

The effect of fish oil on inflammation markers in adult patients undergoing hemodialysis: A meta-analysis

OBJECTIVE

This meta-analysis was to assess the effect of fish oil supplementation on inflammation markers in adult patients receiving hemodialysis.

METHODS

CENTRAL, EMBASE, MEDLINE databases were searched from inception to 10 April 2020. Two authors independently searched, selected, and screened the literature. The pooled results are represented by WMD or SMD with 95% confidence intervals. Subgroup analysis and meta-regression were used to explore sources of heterogeneity, and sensitivity analysis was used to assess the robustness of the pooled results. Funnel plots were used to assess publication bias.

RESULTS

Eleven RCT (randomized control trials) studies were included. The pooled results showed that fish oil supplementation caused a significant reduction of the CRP(C-reactive protein) level (random model: WMD, -3.36, 95%CI: -5.46 to -1.26, P = .002), especially in patients with baseline CRP ≥ 5 mg/L (random model: WMD, -4.43, 95%CI: -6.10 to -2.76, P = .00001, I²  = 41%). Meta-regression analyses showed that CRP baseline level (CRP < 5 mg/L) was the main source of heterogeneity (P = .036). Sensitive analyses revealed that the result was hardly changed. Fish oil supplementation might not reduce the level of IL-6 (random model: WMD, -2.26, 95%CI: -19.61 to 15.09, P = .80) in four studies or the level of TNF-α (random model: SMD, -2.51, 95%CI: -6.08 to 1.06, P = .17) in three studies.

CONCLUSIONS

Fish oil supplementation could reduce the level of CRP in hemodialysis patients, especially in patients with CRP ≥ 5 mg/L, but had no effects on IL-6 and TNF-α.

Lowering effects of fish oil supplementation on proinflammatory markers in hypertension: results from a randomized controlled trial

Reduced inflammation is one of the potential mechanisms underlying the cardioprotective efficacy of fish oil enriched with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Supplementation with fish oil has favorable effects on cardiometabolic profiles in Inner Mongolia patients with hypertension, but whether the cardiovascular benefits can be ascribed to reduced subclinical inflammation is unclear among this population. Seventy-seven middle-aged/elderly hypertensive volunteers were randomly assigned to receive either fish oil (FO, n = 38, 2 g day-1 EPA + DHA) or control corn oil (CO, n = 39) for 90 days. FA compositions in erythrocytes and C-reactive protein (CRP, mg L-1), interleukin-6 (IL-6, pg mL-1) and tumor necrosis factor-α (TNF-α, pg mL-1) concentrations in the plasma were measured before and after the 90-day supplementation, and the cardiometabolic risk was expressed as continuously distributed z-scores calculated by standardizing and then summing the individual cardiovascular risk factors. Significant reductions in the TNF-α (-1.87 ± 2.71 vs. -0.64 ± 2.62, p = 0.02) and CRP levels (-0.85 ± 2.49 vs. 0.56 ± 2.14, p = 0.01) were found in the FO group compared with the CO group, but not in the IL-6 levels (-0.66 ± 1.05 vs. -0.25 ± 0.94, p = 0.10). The decreases in the changes of TNF-α levels were positively correlated with the reductions in the cardiometabolic risk scores in the subjects supplemented with FO (r = 0.35, p = 0.02), but not in the control subjects supplemented with CO (r = 0.09, p = 0.54). FO supplementation increased the levels of EPA (p = 0.013), DHA (p = 0.040) and total n-3 FA (p = 0.035), and decreased the levels of 20:4n-6 (p = 0.041) and total n-6 FA (p = 0.011) and the ratio of n-6 to n-3 FA (p = 0.001), compared with the changes related to the CO group. The increases in the changes of erythrocyte total n-3 FA levels were inversely correlated with the concentrations of TNF-α (r = -0.34, p = 0.001) and CRP (r = -0.29, p = 0.020). The present findings suggest that fish oil supplementation may attenuate the proinflammatory reactions in hypertension, which might help promote the cardiometabolic benefits in this Inner Mongolia population.

Biomarkers of meat and seafood intake: an extensive literature review

Meat, including fish and shellfish, represents a valuable constituent of most balanced diets. Consumption of different types of meat and fish has been associated with both beneficial and adverse health effects. While white meats and fish are generally associated with positive health outcomes, red and especially processed meats have been associated with colorectal cancer and other diseases. The contribution of these foods to the development or prevention of chronic diseases is still not fully elucidated. One of the main problems is the difficulty in properly evaluating meat intake, as the existing self-reporting tools for dietary assessment may be imprecise and therefore affected by systematic and random errors. Dietary biomarkers measured in biological fluids have been proposed as possible objective measurements of the actual intake of specific foods and as a support for classical assessment methods. Good biomarkers for meat intake should reflect total dietary intake of meat, independent of source or processing and should be able to differentiate meat consumption from that of other protein-rich foods; alternatively, meat intake biomarkers should be specific to each of the different meat sources (e.g., red vs. white; fish, bird, or mammal) and/or cooking methods. In this paper, we present a systematic investigation of the scientific literature while providing a comprehensive overview of the possible biomarker(s) for the intake of different types of meat, including fish and shellfish, and processed and heated meats according to published guidelines for biomarker reviews (BFIrev). The most promising biomarkers are further validated for their usefulness for dietary assessment by published validation criteria.

Blood Fatty Acid Status and Clinical Outcomes in Dialysis Patients: A Systematic Review

Blood fatty acids (FAs) are derived from endogenous and dietary routes. Metabolic abnormalities from kidney dysfunction, as well as cross-cultural dietary habits, may alter the FA profile of dialysis patients (DP), leading to detrimental clinical outcomes. Therefore, we aimed to (i) summarize FA status of DP from different countries, (ii) compare blood FA composition between healthy controls and DP, and (iii) evaluate FA profile and clinical endpoints in DP. Fifty-three articles from 1980 onwards, reporting FA profile in hemodialysis and peritoneal DP, were identified from PubMed, Embase, and the Cochrane library. Studies on pediatric, predialysis chronic kidney disease, acute kidney injury, and transplant patients were excluded. Moderate to high levels of n-3 polyunsaturated fatty acids (PUFA) were reported in Japan, Korea, Denmark, and Sweden. Compared to healthy adults, DP had lower proportions of n-3 and n-6 PUFA, but higher proportion of monounsaturated fatty acids. Two studies reported inverse associations between n-3 PUFAs and risks of sudden cardiac death, while one reported eicosapentaenoic acid + docosahexaenoic acid)/arachidonic acid ratio was inversely associated with cardiovascular events. The relationship between all-cause mortality and blood FA composition in DP remained inconclusive. The current evidence highlights a critical role for essential FA in nutritional management of DP.

Associations of fish oil and vitamin B and E supplementation with cardiovascular outcomes and mortality in people receiving haemodialysis: a review

Background

Cardiovascular complications are the leading cause of mortality in patients with end-stage kidney disease. Research indicates that the Mediterranean diet is protective of cardiovascular disease in the general population. Components of this diet have been trialled in haemodialysis patients with the aim of reducing the risk of cardiovascular disease and improving associated risk factors. Components include fish, fruit and vegetables in the form of fish oil supplements and vitamin and antioxidant supplements. This narrative review provides an overview of observational studies, and interventional and randomised controlled trials examining the association of these supplements with cardiovascular outcomes in haemodialysis patients.

Methods

We reviewed the relevant literature by searching English-language publications in Web of Science and references from relevant articles published since 1992. Eight-seven abstracts were reviewed and 38 relevant articles were included.

Results

The extant literature suggests that risk of mortality is reduced in patients with a higher fish intake and those with higher serum omega-3 fatty acid levels. However, the pathways by which risk of mortality is reduced have not been fully extrapolated. While only a few studies have examined the effect of vitamin B supplementation in haemodialysis patients, these studies suggest that supplementation alone does not reduce the risk of mortality. Finally, studies examining vitamin E supplementation have drawn inconsistent conclusions regarding its pro-oxidant or antioxidant effects. Differences between studies are likely due to methodological variations in regards to dose, route of administration and treatment duration.

Conclusions

Nutritional and dietary supplementation in haemodialysis patients is an area which requires larger, more methodologically robust randomised controlled trials to determine if risk of cardiovascular outcomes can be improved.