Marine oil supplements curb pain of rheumatoid, but not osteoarthritis

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  • Marine oil supplements alleviate the pain of rheumatoid arthritis but not osteoarthritis, according to a meta-analysis.

Why this matters

  • 22.7% of US adults report medically diagnosed arthritis.

Study design

  • 42 randomized controlled trials met eligibility criteria after a search on PubMed, the Cochrane Library, EMBASE, Web of Science,, and WHO International Clinical Trial Registry Platform portal.
  • Cochrane Risk of Bias tool was used to evaluate risk for bias.
  • The Grading of Recommendations Assessment, Development, and Evaluation criteria were used to evaluate the quality of the evidence.
  • Funding: No external funding was used.

Key results

  • The standardized mean difference (SMD) across eligible trials was favorable (SMD=−0.24).
  • The SMD was significant for rheumatoid arthritis (22 trials; n=956; SMD=−0.21) and other or mixed rheumatoid/osteoarthritis (3 trials; n=150; SMD=−0.63).
  • The SMD was not significant for osteoarthritis (5 trials; n=403; SMD=−0.17).
  • The rheumatoid arthritis studies were of moderate quality, but the studies of other/mixed arthritis and osteoarthritis were of low quality.


  • High heterogeneity across primary studies.