Impact of Ultra-Processed Food Reduction on Remission Duration in Pediatric Crohn's Disease

Crohn's disease (CD) is a chronic inflammatory bowel disease that often begins during childhood or adolescence and requires lifelong treatment. While pharmacological therapies are effective in inducing and maintaining remission, dietary factors are increasingly recognized as important modifiers of disease activity. Exclusive enteral nutrition and several whole-food dietary approaches have demonstrated that nutrition can influence intestinal inflammation. Observational studies have also reported that higher consumption of ultra-processed foods is associated with an increased risk of Crohn's disease, greater disease activity, and a higher risk of relapse. However, no randomized controlled trial has evaluated whether reducing ultra-processed food intake can prolong remission in pediatric patients with Crohn's disease.

The objective of this randomized controlled trial is to determine whether regular dietary counseling aimed at reducing the consumption of ultra-processed foods can prolong remission in children and adolescents with Crohn's disease receiving standard medical care. The intervention is designed to support gradual and sustainable dietary changes rather than short-term restrictive dieting, with the goal of increasing the proportion of minimally processed foods (NOVA category 1) in the habitual diet while maintaining adequate nutritional intake and normal growth.

Participants aged 10-18 years with Crohn's disease who have maintained clinical remission for at least three months will be randomly assigned in a 1:1 ratio to either the intervention or the control group. Both groups will receive the same number of consultations with a registered dietitian throughout the 12-month study period. In the intervention group, consultations will focus on identifying major sources of ultra-processed foods and supporting families in reducing their consumption using individualized, practical strategies. The control group will receive standard dietary counseling focused on healthy eating without specific recommendations regarding ultra-processed food intake. This design allows the effect of reducing ultra-processed foods to be evaluated while minimizing differences in participant contact and attention between study groups.

Participants will be followed for 12 months during routine outpatient visits. At each study visit, information on disease activity, medical treatment, anthropometric measurements, laboratory parameters, and dietary intake will be collected. Intake of ultra-processed foods will be assessed using a modified version of the validated Processed Food Questionnaire (PFQ), adapted for the pediatric population and Czech dietary habits. Adherence to the intervention will also be evaluated using a dedicated questionnaire.

The primary objective is to evaluate whether the intervention increases the proportion of patients who remain in clinical remission after 12 months. Secondary objectives include evaluation of time to relapse, the association between the magnitude of reduction in ultra-processed food intake and clinical outcomes, and assessment of the safety of the intervention. Particular attention will be paid to growth, nutritional status, iron status, albumin concentrations, and other adverse events to ensure that dietary modification does not compromise nutritional adequacy in this pediatric population.

If successful, this study will provide the first randomized evidence regarding whether reduction of ultra-processed food consumption can improve long-term outcomes in pediatric Crohn's disease. The findings may inform future dietary recommendations and provide an evidence-based, non-pharmacological strategy to complement standard medical therapy in maintaining remission.