This project proposes to conduct the first fully controlled and randomized clinical study demonstrating the impact of DPA-rich sea bass oil on the reduction of symptoms related to rheumatoid arthritis. This unique approach will allow to clinically evaluate the benefits of sea bass oil on the relief of rheumatoid arthritis-related pain in a population suffering from inflammatory arthritis.

The main objective of this project is to measure the efficacy of DPA-rich marine seal oil in improving the clinical signs and symptoms associated with rheumatoid arthritis through the score calculated from the Rheumatoid Arthritis Disease Activity Index (RADAI) questionnaire, in patients suffering from this disease.

The secondary objectives are to evaluate the effect of DPA-rich seal oil on:

1. the degree of disease activity as measured by a joint examination performed by the physician
2. the patient's overall health, quality of life and level of fatigue
3. blood biomarkers of inflammation (CRP: c-reactive protein, TNF-: tumor necrosis factor, IL-1, IL-6 and IL-17: interleukin);
4. the use of non-steroidal anti-inflammatory drugs (NSAIDs);
5. the occurrence of side effects.

To do so, the proposed study is a multi-center, randomized, double-blind, parallel-designed study involving 130 participants with a previous diagnosis of RA from two research and treatment centers in Quebec: the "Groupe de recherche en rhumatologie et maladies osseuses" (GRMO Inc.) from Québec and the "Centre de recherche musculo-squelettique" (CRMS) from Centre du Québec. Rheumatologists from each of the centers, as well as research nurses, will be involved in this project, which will be coordinated by a research professional from the Institut sur la nutrition et les aliments fonctionnels (INAF) at Université Laval. Half of the participants (n=65) will randomly receive the experimental treatment (marine seal oil) while the other half will receive the control treatment (vegetable oil). In order to reach a minimum blood concentration of omega-3 fatty acids for measurable effects, the experimental and control treatments will be administered over a 12-week period.

Inclusion Criteria:

• Have been diagnosed with RA after the age of 18;

• Have had RA for at least 1 year;

• Meet the 2010 ACR/EULAR criteria;

• Stable disease status for at least 3 months:

  • Low to moderate activity as measured by the Clinical Disease Activity Index (CDAI);
  • Stable dose of DMARD (conventional synthetic Disease Modifying Anti-Rheumatic Drug) for at least 3 months;
  • Stable dose of NSAIDs and corticosteroids for at least 1 month;
  • Do not take > 10 mg per day of prednisone.

Exclusion Criteria:

• Have been diagnosed with another rheumatologic autoimmune disease;
• Have been diagnosed with inflammatory bowel disease (ulcerative colitis or Crohn's disease);
• Have a disease that may interfere with the physician's assessment (e.g. severe osteoarthritis);
• Have fibromyalgia;
• Consume omega-3 fatty acid supplements other than those given during the project;
• Have an allergy or intolerance to seafood;
• Consume natural health products that may potentially affect inflammation (e.g. glucosamine, chondroitin, devil's claw, curcumin products) during the project;
• Consume more than two servings (1 serving = 90 g or 3 ounces) of fish and seafood per week for the duration of the study;
• Take anticoagulant medication;
• Be treated or have previously received biological agents or inhibitors of JAK (Janus kinase) (family of tyrosine kinases).

Double-blind