Prospective study of an amino acid–based elemental diet in an eosinophilic gastritis and gastroenteritis nutrition trial

Background: Eosinophilic gastritis/gastroenteritis (EoG/EoGE) are rare disorders with pathologic gastric and/or small intestinal eosinophilia lacking an approved therapy. An allergic mechanism is postulated but underexplored mechanistically and therapeutically. Objective: We evaluated the effectiveness of a food allergen–free diet (elemental formula) in controlling gastrointestinal eosinophilia in adult EoG/EoGE. Methods: Adults aged 18 to 65 years with histologically active EoG/EoGE (≥30 eosinophils per high-power field) in the stomach and/or duodenum and gastrointestinal symptoms within the month preceding enrollment were prospectively enrolled onto a single-arm clinical trial to receive elemental formula for 6 consecutive weeks. The primary end point was percentage of participants with complete histologic remission (<30 eosinophils per high-power field in both stomach and duodenum). Exploratory outcomes were improvement in symptoms, endoscopy results, blood eosinophilia, quality of life, Physician Global Assessment score, and EoG-relevant gastric transcriptome and microbiome. Results: Fifteen adults (47% male, average age 37.7 years, average symptom duration 8.8 years) completed the trial. Multi–gastrointestinal segment involvement affected 87%. All subjects had complete histologic remission in the stomach (P =.002) and duodenum (P =.001). Scores improved in overall PhGA (P =.002); EGREFS (P =.003); EGDP (P =.002); SODA pain intensity (P =.044), non-pain (P =.039), and satisfaction (P =.0024); and PROMIS depression (P =.0078) and fatigue (P =.04). Food reintroduction reversed these improvements. The intervention was well tolerated in 14 subjects, with 1 serious adverse event reported in 1 subject. Conclusion: An amino acid–based elemental diet improves histologic, endoscopic, symptomatic, quality-of-life, and molecular parameters of EoG/EoGE; these findings and disease recurrence with food trigger reintroduction support a dominant role for food allergens in disease pathogenesis. ClinicalTrials.gov Identifier: NCT03320369.