Effects of nutritional supplements and dietary interventions on rheumatoid arthritis: An umbrella review of meta-analyses of randomized controlled trials

Abstract

Backgrounds: The effects of nutritional supplements and dietary interventions on rheumatoid arthritis (RA) are still unclear.

Objectives: This study aimed to evaluate the impact of nutritional supplements and dietary interventions on RA patients.

Methods: The online databases of PubMed, Web of Science, Embase, and Cochrane Library were used to search the relevant literature from inception to December 2024. Meta-analyses with the inclusion of randomized controlled trials were selected to assess the effects of nutritional supplements or dietary interventions on RA. We accessed the methodological quality of included reviews using AMSTAR 2 and evaluated the quality of evidence for intervention effects using GRADE. Data synthesis and analysis were used by R 4.4.1 and STATA 17.

Results: A total of 14 articles were included, evaluating the effects of nutritional supplements and dietary interventions on RA management. Among these, 3 studies were rated as high quality, 6 as low quality, and 5 as critically low quality by AMSTAR2. The quality of evidence for intervention effects ranges from low to very low quality. The interventions assessed included polyunsaturated fatty acids (PUFAs), probiotics, total glucosides of paeony (TGP), anti-inflammatory diets (AIDs), and others. TGP was the only intervention to significantly reduce both the disease activity score and erythrocyte sedimentation rate, although the quality of evidence for these effects was low. Probiotics contributed to significant reductions in C-reactive protein and visual analogue scale scores, with both outcomes rated as low quality. PUFAs demonstrated significant improvements in tender joint count, swollen joint count, and morning stiffness, though, like the other interventions, these effects were also rated as low quality.

Conclusion: There was relatively strong evidence supporting that PUFAs, probiotics, TGP, and AIDs may show some benefits on RA. However, the low quality of evidence highlights the need for further high-quality research and real-world evidence to confirm their effectiveness.

Keywords: Diet; Nutritional supplements; Rheumatoid arthritis; Umbrella review.