Effects of vegetarian and vegan diets on disease activity, pain, fatigue, and physical function in patients with rheumatoid arthritis: A systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 40907874 · doi:10.1016/j.jbspin.2025.105958
What was done
Researchers searched MEDLINE, EMBASE, CINAHL, and CENTRAL through December 2024 for randomized controlled trials assessing vegan or vegetarian diets (including lacto-ovo-vegetarian, vegan, and whole-food plant-based diets) in people with rheumatoid arthritis. Evaluated outcomes included disease activity, pain, fatigue, and physical function compared to control diets. Certainty of evidence was rated using the GRADE framework.
What was found
Seven trials published between 1979 and 2023 were included from 1,408 screened records. The abstract provides no numerical effect estimates or confidence intervals. Pooled analyses revealed a small significant improvement in pain with vegetarian or vegan diets compared to controls, but no significant improvements in disease activity or physical function. Fatigue was evaluated in only one study and could not be meta-analyzed. Sensitivity and subgroup analyses did not change the results, and GRADE certainty was rated as low across all outcomes.
Why it matters
Patients with rheumatoid arthritis often try dietary changes to control symptoms, but current trial evidence indicates plant-based diets provide at most modest pain relief without altering objective disease activity or function.
Limits
The total number of participants is not reported in the abstract, and only seven trials spanning more than four decades were eligible. Methodological limitations were present across the included studies, fatigue was understudied, and the overall certainty of evidence is low.
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