Objective: To assess the clinical efficacy and side effects of gammalinolenic acid, a plant-seed-derived essential fatty acid that suppresses inflammation and joint tissue injury in animal models.
Design: A randomized, double-blind, placebo-controlled, 24-week trial.
Setting: Rheumatology clinic of a university hospital.
Patients: Thirty-seven patients with rheumatoid arthritis and active synovitis.
Intervention: Treatment with 1.4 g/d gammalinolenic acid in borage seed oil or cotton seed oil (placebo).
Measurements: Physicians' and patients' global assessment of disease activity; joint tenderness, joint swelling, morning stiffness, grip strength, and ability to do daily activities.
Results: Treatment with gammalinolenic acid resulted in clinically important reduction in the signs and symptoms of disease activity in patients with rheumatoid arthritis (P < 0.05). In contrast, patients given a placebo showed no change or showed worsening of disease. Gammalinolenic acid reduced the number of tender joints by 36%, the tender joint score by 45%, swollen joint count by 28%, and the swollen joint score by 41%, whereas the placebo group did not show significant improvement in any measure. Overall clinical responses (significant change in four measures) were also better in the treatment group (P < 0.05). No patients withdrew from gammalinolenic acid treatment because of adverse reactions.
Conclusion: Gammalinolenic acid in doses used in this study is a well-tolerated and effective treatment for active rheumatoid arthritis. Gammalinolenic acid is available worldwide as a component of evening primrose and borage seed oils. It is usually taken in far lower doses than used in this trial. It is not approved in the United States for the treatment of any condition and should not be viewed as therapy for any disease. Further controlled studies of its use in rheumatoid arthritis are warranted.