Clinical Outcomes and Food Triggers Following Low Food Chemical Diet Implementation: A Retrospective Audit of Dietetic Practice

INTRODUCTION: Food hypersensitivity describes a range of nonimmune food related reactions of varying aetiology causing gastrointestinal and extraintestinal symptoms. This study aimed to evaluate if the low-chemical diet improves gastrointestinal and/or extraintestinal symptoms, and whether specific food challenges induce symptoms. METHODS: A retrospective clinical audit was conducted on files from 2011 to 2022 from a gastrointestinal specialist dietetic practice. Fifty eligible patient files were identified, all of whom had been recommended to follow a low-chemical diet. One research dietitian extracted data on diet implementation, symptom change during the Restrictive Phase, and symptom provocation during the Rechallenge Phase. Descriptive statistics were used. RESULTS: The cohort was predominantly female (80%), mean age 47 years (range 7-85). At baseline the most common gastrointestinal symptom was diarrhoea (22/50, 44%), and extraintestinal symptom was nasal congestion (14/50, 28%). Improvement in at least one symptom following the Restrictive Phase occurred in 88% (44/50). The Restrictive Phase was followed for 2-78 weeks, and unintentional weight loss was documented in 24% (2-10 kg). The Rechallenge Phase duration ranged from 5 to 191 weeks, with 96% (48/50) reporting symptom provocation following at least one challenge. Salicylate challenge most commonly induced diarrhoea (16%), bloating (16%), and itch (14%), while amine challenge induced abdominal pain (10%) and nausea (8%). CONCLUSION: Patients reported an improvement in gastrointestinal and extraintestinal symptoms, but commonly experienced prolonged dietary restriction. Rechallenge with salicylates and amines provoked symptoms; but this may be confounded by other diet and non-diet factors. High-quality trials with isolated food chemical components are needed.<p></p>