Immune-Based Personalized Elimination Diet for the Treatment of Irritable Bowel Syndrome: A Double-Blind Randomized Sham-Controlled Study

Introduction: Dietary intervention is a common treatment among patients with irritable bowel syndrome (IBS). However, insufficient patient adherence, and essential need for ingredient restrictions limiting its use in this population. Immune assay guided diet may provide an individualized intervention, which may increase its effectiveness compared with non-personalized dietary strategies. We aimed to test the effectiveness of an individualized dietary intervention, based on Leukocyte activation to dietary components (Alcat, Germany), to improve patient compliance to diet modifications. Methods: A randomized, double-blind, 2-arm trial, comparing the efficacy of Alcat-diet versus a “Sham” balanced diet for 8-week treatment of IBS. The primary outcome was defined as a reduction of ≥50 points on the IBS-severity scoring system (IBS-SSS). Secondary outcomes included the raw scores of IBS-SSS, Irritable Bowel Syndrome Quality of Life Questionnaire (IBS-QoL) and the Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS). IBS-Adequate Response rate and the rates of moderate / substantial improvement on the IBS Global assessment of improvement (IBS-GAI) and the IBS Global Improvement Scale (IBS-GIS) were documented. Results: Sixty-eight patients with IBS-D (44) and IBS-M (24) were enrolled. At baseline, patients in the Alcat-group had a higher median IBS-SSS score compared with the controls (390 [305-435] vs 330 [240-390], respectively, P=0.013). At week 8 of dietary intervention, 30/35 (85.7%) patients in the Alcat-group met the primary outcome, compared with 18/33 (54.5%) of the controls (P=0.005). After 8 weeks, there were higher rates of patients in the Alcat-group who reported a symptomatic improvement (i.e., positive response: 85.7% vs 57.6%, P=0.010 and IBS-GIS: 74.3% vs 42.4%, P=0.008, Δ VAS-IBS abdominal pain score: 49.7±29.8 vs 31.6±28.8, P=0.020) compared with the controls. Alcat-diet was more beneficial for patients who were naïve to dietary-intervention (ΔIBS-SSS≥50 rate: 100% vs 57%, respectively, P=0.010), than patients who had previously tried any dietary-intervention (ΔIBS-SSS≥50 rate: 77% vs 50%, respectively, P=0.148) compared with the Sham-diet. No serious adverse events were reported during follow-up. Conclusion: Immune-based personalized diet was more efficient than Sham-diet for reducing symptoms in IBS patients, and may serve as a safe treatment option in this population (Figure 1).Figure 1.: Study outcome rates at the end of follow-up (8-week time point) divided to the Alcat-based diet group and the Sham-based diet group. Abbreviations: Irritable bowel syndrome, IBS; IBS Symptom Severity Scale, IBS-SSS; IBS global assessment of improvement, IBS-GAI; IBS global improvement scale, IBS-GIS.