Diet, Ultra-Processed Foods, and Food Additives in Crohn’s Disease: A Comprehensive Review

Background and aim: Crohn’s disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract resulting from a complex interplay among genetic susceptibility, immune dysregulation, environmental factors, and alterations in the gut microbiota. Among these, diet has emerged as a key modifiable factor influencing intestinal inflammation, barrier integrity, and disease progression. This review aims to critically evaluate the role of dietary patterns and food additives in the pathogenesis and management of Crohn’s disease, with particular emphasis on their effects on intestinal inflammation, epithelial barrier function, and host–microbiota interactions. Methods: A comprehensive literature search was conducted using the PubMed, Scopus, and Web of Science databases up to March 2026. Clinical trials, observational studies, and mechanistic research were included based on their relevance to dietary factors, food additives, and intestinal inflammation in CD. Evidence was synthesized narratively to integrate clinical and experimental findings. Results: Dietary interventions such as the Crohn’s disease exclusion diet (CDED), specific carbohydrate diet (SCD), low-FODMAP diet, and Mediterranean diet (MD) demonstrate varying degrees of efficacy in improving clinical symptoms and, in some cases, inflammatory markers. In contrast, high consumption of ultra-processed foods is consistently associated with increased disease risk and activity. Emerging evidence highlights the role of food additives—particularly emulsifiers and artificial sweeteners—in disrupting gut barrier integrity, promoting dysbiosis, and enhancing inflammatory responses. Recent human studies further suggest that exposure to these compounds may correlate with disease activity, supporting their potential role in CD pathophysiology. Conclusions: Diet plays a significant adjunctive role in the management of Crohn’s disease. Reducing exposure to ultra-processed foods and potentially harmful food additives, while promoting balanced dietary patterns, may improve clinical outcomes. Further research is needed to clarify long-term effects and to develop personalized, evidence-based nutritional strategies for patients with CD.