Effect of Marine-Derived n-3 Polyunsaturated Fatty Acids on C-Reactive Protein, Interleukin 6 and Tumor Necrosis Factor α: A Meta-Analysis
What this study found
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);…
- Study & population
- This meta-analysis included 68 studies with 4601 adults, spanning healthy individuals and patients with chronic non-autoimmune disease or chronic autoimmune disease.
- Intervention
- 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.
- Key limitation
- The included evidence was highly heterogeneous in population, dose, formulation, duration, and exposure source, which limits direct comparability across studies.
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Open PDFOriginal abstract
Background Previous studies did not draw a consistent conclusion about the effects of marine-derived n-3 polyunsaturated fatty acids (PUFAs) on fasting blood level of C-reactive protein (CRP), interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α). Methods and Findings A comprehensive search of Web of Science, PubMed, Embase and Medline (from 1950 to 2013) and bibliographies of relevant articles was undertaken. Sixty-eight RCTs with a total of 4601 subjects were included in the meta-analysis. Marine-derived n-3 PUFAs supplementation showed a lowering effect on Marine-derived n-3 PUFAs supplementation had a significant lowering effect on TNF-α, IL-6 and CRP in three groups of subjects (subjects with chronic non-autoimmune disease, subjects with chronic autoimmune disease and healthy subjects). A significant negative linear relationship between duration and effect size of marine-derived n-3 PUFAs supplementation on fasting blood levels of TNF-α and IL-6 in subjects with chronic non-autoimmune disease was observed, indicating that longer duration of supplementation could lead to a greater lowering effect. A similar linear relationship was also observed for IL-6 levels in healthy subjects. Restricted cubic spline analysis and subgroup analysis showed that the lowering effect of marine-derived n-3 PUFAs on CRP, IL-6 and TNF-α in subjects with chronic non-autoimmune disease became weakened when body mass index was greater than 30 kg/m2. The effect of marine-derived n-3 PUFAs from dietary intake was only assessed in subjects with chronic non-autoimmune disease, and a significant lowering effect was observed on IL-6, but not on CRP and TNF-α. Conclusions Marine-derived n-3 PUFAs supplementation had a significant lowering effect on CRP, IL-6 and TNF-α level. The lowering effect was most effective in non-obese subjects and consecutive long-term supplementation was recommended.