Rheumatoid arthritis is driven by an aberrant immune response that produces chronic joint inflammation. While the underlying immunological trigger is genetic and environmental, the severity of joint inflammation at any given time is substantially influenced by dietary factors that modulate systemic and local inflammatory signalling. Multiple systematic reviews have examined dietary interventions in RA, finding consistent but moderate effects from anti-inflammatory dietary patterns.
The Mediterranean Diet in RA
A randomised controlled trial published in the Annals of the Rheumatic Diseases found that RA patients assigned to a Mediterranean diet for 12 weeks showed significantly greater reductions in DAS28 disease activity scores, morning stiffness, and tender joint counts compared to a standard Western diet control group. The Mediterranean diet group also showed significant improvements in physical function and vitality scores. The anti-inflammatory mechanism operates through multiple pathways including omega-3 to omega-6 ratio normalisation, polyphenol NF-kappaB inhibition, and gut microbiome modulation.
Omega-3 Fatty Acids in RA: The Trial Evidence
A meta-analysis of 20 randomised controlled trials in RA patients found that omega-3 supplementation equivalent to consuming three to four portions of oily fish per week significantly reduced joint swelling, morning stiffness, patient-reported pain, and NSAID requirement. The effect was dose-dependent. The mechanism involves competitive inhibition of arachidonic acid pathways that produce the pro-inflammatory prostaglandins and leukotrienes that maintain synovial inflammation.