Quantitative and qualitative assessment of diet and its association with disease activity in pediatric ulcerative colitis.

Objectives: Ulcerative colitis (UC) is a chronic inflammatory bowel disease with increasing global prevalence, particularly in newly industrialized countries. While diet has been implicated in disease pathogenesis, its role in modifying clinical outcomes remains unclear. This study aimed to evaluate dietary intake and habits in pediatric UC patients and assess their association with clinical remission (CR) and mucosal healing (MH).

Methods: A cross-sectional study was conducted in a Spanish tertiary hospital, including UC patients aged 8-18 years. Dietary assessment was performed using a 3-day food diary, dietary questionnaires, and the NOVA classification. K-means clustering identified dietary patterns associated with CR and MH. Predictive models were developed using logistic regression, random forest, and gradient boosting.

Results: A total of 47 patients were included. Patients in Cluster 1 (CR + MH) exhibited superior dietary quality, characterized by a higher intake of unprocessed/minimally processed foods, fiber, and essential micronutrients (p < 0.05). Conversely, patients without CR or MH (Cluster 3) had a diet rich in ultra-processed foods (UPFs) and saturated fats (p < 0.01). UPFs intake and poor dietary quality were significant predictors of worse outcomes, independent of pharmacological therapy.

Conclusions: Dietary quality was associated with both disease activity and treatment response. While these findings highlight a potentially relevant relationship, the cross-sectional nature of the study precludes establishing causality. Higher consumption of minimally processed foods and specific micronutrients was associated with better clinical outcomes, while UPFs intake correlated with persistent inflammation. These findings highlight the importance of integrating dietary strategies into UC management to optimize therapeutic outcomes.