Associations of cereal fiber intake with rheumatoid arthritis mediated by dietary inflammatory index: insights from NHANES 2011–2020

Abstract Rheumatoid Arthritis (RA) is an increasingly prevalent inflammatory disorder worldwide. Its complex etiology has recently brought dietary factors, particularly fiber intake, into focus as potential influencers. Our study investigates the intricate relationship between various sources of dietary fiber and RA, emphasizing the mediating role of the Dietary Inflammatory Index (DII). Leveraging data from the National Health and Nutrition Examination Survey spanning 2011 to 2020. We meticulously assessed dietary fiber intake through dual 24 h dietary recall interviews, while RA diagnoses were established based on comprehensive medical surveys. The relationships between fiber intake, RA prevalence, and DII mediation were analyzed using sophisticated multivariate logistic regression and mediation analysis. Among our study cohort, 7% were diagnosed with RA. We observed a notable inverse correlation between increased total fiber intake, particularly 5 g/day increments, and the incidence of RA, with cereal fiber intake emerging as the primary mitigating factor. Intriguingly, the DII played a significant role in mediating this association, especially regarding cereal fiber. Our findings reveal a significant association between higher cereal fiber consumption and a reduced prevalence of RA. Additionally, the DII stands out as a pivotal mediator in this relationship, highlighting dietary management's critical role in preventing and managing RA.