Effect of Marine-Derived n-3 Polyunsaturated Fatty Acids on C-Reactive Protein, Interleukin 6 and Tumor Necrosis Factor α: A Meta-Analysis

This meta-analysis included 68 studies with 4601 adults, spanning healthy individuals and patients with chronic non-autoimmune disease or chronic autoimmune disease. The review compared marine-derived n-3 PUFA supplementation or dietary intake with control conditions and examined whether effects differed by health status, source of n-3 PUFA, duration, and adiposity.

The intervention was marine-derived n-3 PUFA supplementation, typically fish oil providing EPA and DHA, with regimens ranging from 14 days to 12 months and total n-3 doses varying widely across included studies. Dietary intake of marine-derived n-3 PUFAs was also evaluated separately from supplementation.

Overall, marine-derived n-3 PUFA supplementation reduced fasting inflammatory markers, with the clearest benefit in chronic non-autoimmune disease, autoimmune disease, and healthy subjects. Supplementation significantly lowered CRP, IL-6, and TNF-α in chronic non-autoimmune disease; in healthy subjects it lowered CRP and TNF-α, with IL-6 showing only a marginal reduction. For dietary intake, a significant reduction was observed for IL-6 in chronic non-autoimmune disease, but not for CRP or TNF-α. Effects tended to be stronger with longer duration and smaller in obese individuals (BMI >= 30); higher EPA dose was linked to greater CRP reduction, while higher DHA dose was associated with greater IL-6 reduction in healthy subjects.

The included evidence was highly heterogeneous in population, dose, formulation, duration, and exposure source, which limits direct comparability across studies. Some subgroup conclusions were based on limited data, including unavailable IL-6 data in autoimmune disease dietary analyses and TNF-α findings supported by only a single marginally significant study. Arm-level outcome estimates were not consistently reported in the provided excerpt, so interpretation relies mainly on pooled review findings.