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

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.

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.

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%).

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.