Effectiveness and safety of dietary interventions for rheumatoid arthritis: a systematic review of randomized controlled trials

Abstract

This systematic review assesses the effectiveness and safety of dietary interventions for rheumatoid arthritis. Randomized controlled trials comparing any dietary manipulation with an ordinary diet were included. Eight randomized controlled trials with a total of 366 patients were included. One trial found that fasting, followed by 13 months on a vegetarian eating plan, might reduce pain (mean difference on a zero to 10 scale -1.89, 95% confidence interval [CI] -3.62 to -0.16). Another single trial found that a 12-week Cretan Mediterranean eating plan might reduce pain (mean difference on a 0 to 100 scale -14.00, 95% CI -23.6 to -4.37). Due to inadequate data reporting, the effects of vegan eating plans and elimination diets are uncertain. When comparing any dietary manipulation with an ordinary diet we found a higher total drop-out of 8% (risk difference 0.08, 95% CI -0.01 to 0.17), higher treatment-related drop-out of 5% (risk difference 0.05, 95% CI -0.03 to 0.14) and a significantly higher weight loss (weighted mean difference -3.24, 95% CI -4.81 to -1.67 kg) in the diet groups compared to the control groups. The effects of dietary manipulation, including vegetarian, Mediterranean, and elemental eating plans, and elimination diets on rheumatoid arthritis are still uncertain due to the included studies being small, single trials with moderate to high risk of bias. We conclude that higher dropout rates and weight loss in the groups with dietary manipulation indicate that potential adverse effects should not be ignored.