Dietary Pattern or Weight Loss: Which One Is More Important to Reduce Disease Activity Score in Patients with Rheumatoid Arthritis? A Randomized Feeding Trial

OBJECTIVES: Herein, disease activity score 28 (DAS 28) was compared between patients with rheumatoid arthritis (RA) receiving the Mediterranean dietary pattern (MD) and low-fat diet. Subjects/Methods. Overweight and obese RA patients aged 15–75 y participated in this randomized feeding trial. Participants were randomized to MD (n = 51) and low-fat high-carbohydrate diet (n = 53) for 12 weeks. The control group followed their regular diet (n = 50). Participants completed the form of tender and swollen joint counts before the study enrollment and after 12 weeks to compute DAS 28. RESULTS: Weight loss was not statistically significant between the MD and LF-HC groups. DAS 28 significantly decreased in MD compared to the LF-HC group (p=0.02) and controls (p=0.001). Adjusting for the baseline variables, MD reduced DAS 28 by 76% (95% CI = −0.45, −0.2; p=0.03) after 12 weeks of intervention. The baseline serum ESR level showed 99.8% effect on DAS 28 score at the end (95% CI = 0.014, 0.035; p < 0.001). CONCLUSIONS: The MD showed beneficial effects on DAS 28 compared to the LF-HC diet in patients with RA, regardless of weight loss. It is a better dietary choice for pain reduction in patients with RA. The trial is registered at Iranian Registry of Clinical Trials (IRCT20200929048876N2).