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

PLoS ONE
Q1
Feb 2014
Citations:231
Influential Citations:11
Systematic Reviews / Meta-Analyses
95
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Methods
68 randomized controlled trials (n=4601) across three populations: healthy adults, adults with chronic non-autoimmune disease, and adults with chronic autoimmune disease; study designs included parallel-group, crossover, and factorial; quality assessed by Cochrane criteria.
Intervention
Oral marine-derived n-3 PUFA supplementation (EPA/DHA) from fish oil, krill oil, or algal oil; regimens varied widely in daily total n-3 intake (roughly 0.3–5.4 g) and duration (30 days to 12 months).
Results
Marine-derived n-3 PUFA supplementation significantly lowers fasting CRP, IL-6 and TNF-α across groups. In chronic non-autoimmune disease, CRP and IL-6 reductions are significant; TNF-α change is not. In autoimmune disease, CRP reduction is significant; TNF-α reduction is marginal; IL-6 data not reported. In healthy subjects, CRP and TNF-α reductions are significant; IL-6 reduction is marginal. Longer duration strengthens IL-6 and TNF-α reductions; higher EPA dose lowers CRP in healthy subjects; higher DHA dose more strongly reduces IL-6 in healthy subjects. Lower BMI (<30 kg/m2) is associated with larger reductions; obesity attenuates effects. Dietary intake of n-3 PUFAs reduces IL-6 but not CRP or TNF-α in chronic non-autoimmune disease. Overall, marine-derived n-3 PUFAs show anti-inflammatory effects and longer-term use is likely more beneficial, especially in non-obese individuals.
Limitations
Risk of bias in several trials; substantial heterogeneity across analyses; mixture of supplementation and dietary intake; wide variation in dose and duration; limited data for some outcomes (e.g., IL-6 in autoimmune disease; TNF-α with dietary intake); potential publication bias in IL-6 analyses.

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)....