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Omega-3 fatty acids may reduce CRP in haemodialysis patients, but evidence is limitedOmega-3 supplements may reduce inflammation in kidney dialysis patients

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Key Takeaway
Consider omega-3's potential CRP reduction in HD patients cautiously; evidence is limited and heterogeneous.

This systematic review and meta-analysis examined the anti-inflammatory effects and safety of omega-3 fatty acid supplementation in 678 haemodialysis patients. The analysis compared omega-3 supplementation to unspecified comparators, with C-reactive protein (CRP) as the primary outcome.

In specific subgroup analyses, omega-3 fatty acids reduced CRP more than comparators. For triglyceride formulations, the standardized mean difference (SMD) was -0.62 (95% CI -1.22 to -0.03; P = 0.04). For total daily doses below 2000 mg, SMD was -0.32 (95% CI -0.61 to -0.04; P = 0.02). For active ingredient doses below 2000 mg/day, SMD was -0.36 (95% CI -0.59 to -0.13; P = 0.003).

Safety data were limited. Eight trials did not report adverse events, while five described only mild, transient effects such as diarrhea. Serious adverse events, discontinuations, and tolerability were not reported.

Key limitations include substantial heterogeneity in the triglyceride formulation analysis (I² 74%), with lower heterogeneity in dose subgroups (I² 29-31%). Two studies were judged high risk of bias, and one unclear. The evidence suggests a daily dose below 2000 mg in natural triglyceride form may be more effective than synthetic ethyl ester formulations for lowering CRP, but this remains an association requiring confirmation.

Researchers analyzed data from 13 previous studies involving 678 people on hemodialysis (kidney dialysis) to see if omega-3 fatty acid supplements could reduce inflammation. They specifically looked at changes in a blood marker called C-reactive protein (CRP). The analysis found that taking omega-3 supplements was associated with lower CRP levels compared to other treatments or placebos. This effect was clearer when people took a daily dose under 2000 mg and when the supplement was in a natural triglyceride form rather than a synthetic type.

Information about side effects was not well documented in most of the studies. A few studies mentioned only mild, temporary issues like diarrhea. No serious safety problems were reported, but the lack of detailed safety data means we cannot be sure about the risks.

The main reason to be careful is that this is a review of existing, smaller studies, not new, large-scale research. The quality of the original studies varied, and the results show a link, not proof that omega-3s caused the reduction in inflammation. Readers should understand that while this is a promising finding for managing inflammation in dialysis patients, it is not yet strong enough to change standard medical practice. More high-quality research is needed to confirm a true benefit and to figure out the best dose and type of omega-3 supplement for this purpose.

What this means for you:
Early analysis links omega-3s to lower inflammation in dialysis patients, but more research is needed to confirm benefits and safety.

Study Details

Study typeMeta analysis
Sample sizen = 345
EvidenceLevel 1
PublishedApr 2026
View Original Abstract ↓
INTRODUCTION: Evidence on the anti-inflammatory effects and safety of omega-3 fatty acid supplementation in haemodialysis (HD) patients remains limited, particularly regarding the influence of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) dose, composition, and source. METHODS: We searched PubMed (n = 345), CENTRAL (n = 148) and EMBASE (n = 706) to July 2025. Studies were screened using Covidence, risk of bias was assessed using the Cochrane ROB 1 tool, and analyses were conducted in Review Manager 9.5.1. Only trials reporting C-reactive protein (CRP) were included. Pre-planned subgroup analyses examined formulation type, total daily dose, active ingredient dose, and DHA:EPA composition. Random-effects models were used to generate pooled standardised mean differences (SMDs), with heterogeneity assessed using I. A sensitivity analysis excluded studies at high risk of bias. The protocol is registered on the Open Science Framework (https://doi.org/10.17605/OSF.IO/JCBHN). RESULTS: Thirteen studies (n = 678) were included (12 in meta-analyses). Two studies were judged high risk of bias, one unclear, and the remainder low risk. Adverse events were poorly reported: eight trials did not report any events, while five described only mild, transient effects (e.g., diarrhoea). Omega-3 fatty acids reduced CRP more than comparators across triglyceride formulations (SMD -0.62, 95 % CI -1.22 to -0.03; P = 0.04, I = 74 %); in the <2000 mg/day total dose subgroup (SMD -0.32, 95 % CI -0.61 to -0.04; P = 0.02, I = 29 %); and in the <2000 mg/day active ingredient subgroup (SMD -0.36, 95 % CI -0.59 to -0.13; P = 0.003, I = 31 %). No statistically significant differences were observed between subgroups. Sensitivity analyses did not materially change the results. CONCLUSION: A daily dose <2000 mg of omega-3 fatty acids in natural triglyceride form appears more effective than synthetic ethyl ester formulations for lowering CRP in HD patients. Larger, high-quality trials are required to confirm therapeutic benefit, determine optimal dosing, and clarify the ideal EPA:DHA composition for this population.
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