From nutritional intervention to immune modulation: a multi-database bibliometric and topic modeling study of vitamin D in inflammatory bowel disease

Background: Inflammatory bowel disease (IBD) is a chronic condition characterized by recurrent inflammatory episodes in the gastrointestinal tract. Conventional therapies, including biologics, corticosteroids, and immunosuppressive drugs, can effectively alleviate disease activity. However, their utility is often limited by adverse effects. Vitamin D plays a role in modulating immune function, intestinal barrier integrity, and the gut microbiota. It has emerged as a promising adjunctive therapy for IBD. Objective: To map the research landscape of vitamin D in IBD using bibliometric analysis, focusing on knowledge evolution, core themes, and emerging trends. Methods: Publications from 2006 to 2025 were collected by searching the Web of Science Core Collection (WoSCC) and Scopus databases. After removing duplicates, 2,659 articles and reviews were obtained for analysis. Networks were constructed using CiteSpace, VOSviewer, R, and Python. PubMed clinical trials were included for complementary analysis, and BERTopic was applied to identify latent topics and their temporal dynamics. Results: A total of 2,659 publications spanning 970 journals were identified, with a steady increase in output. The USA was the leading contributor and also demonstrated strong international collaboration. Ananthakrishnan Ashwin N. was the most influential author, and Inflammatory Bowel Diseases was the journal with the leading journal. Core themes included vitamin D deficiency, gut microbiota, inflammatory response, diet and nutrition. The focus has shifted toward gut microbiota, immune regulation, micronutrients, and evidence-based approaches. Furthermore, BERTopic modeling identified 12 latent topics, with increasing emphasis on gut microbiota, fecal microbiota transplant, and nutritional deficiencies. Conclusion: This bibliometric analysis provides a concise, data-driven overview of research on vitamin D in IBD. The results highlighting its structure, evolution, and emerging trends, and informing future mechanistic and translational research.