Objectives: Pain is a significant problem in rheumatoid arthritis (RA) and is associated with prostaglandins derived from the ω-6 polyunsaturated fatty acid (PUFA) arachidonic acid. The ω-3 PUFAs eicosapentaenoic acid and docosahexaenoic acid have been shown to reduce inflammation, with some studies showing clinical improvements in RA. The aim of this systematic review was to investigate the effect of ω-3 PUFAs on arthritic pain.
Method: A systematic literature review of ω-3 PUFAs and pain associated with RA was performed up to December 2015. Randomized controlled trials (RCTs) investigating the effect of ω-3 PUFAs (>2 g/d) on patient or physician assessment of pain, or assessment by both patient and physician, were included. The Cochrane Collaboration's tool for assessing risk for bias was employed. Data for outcomes of interest were extracted and collated for interpretation.
Results: Eighteen RCTs published between 1985 and 2013 involving 1143 patients were included. Dosage of ω-3 PUFAs used was 2.1 to 9.1 g/d, with study durations of 12 to 52 wk. Ten studies supported the hypothesis that there is a reduction in patient or physician assessment of pain associated with RA after intake of ω-3 PUFAs. Eight studies found no statistically significant effect of ω-3 PUFAs on arthritic pain.
Conclusions: ω-3 PUFAs may have a therapeutic role in decreasing pain associated with RA, with doses of 3 to 6 g/d appearing to have a greater effect. Due to the limitations identified in the RCTs included in this review, more research is needed to investigate ω-3 PUFAs in larger populations and over extended periods of time.
Keywords: DHA; EPA; Fish oil; Pain; Rheumatoid arthritis.
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