Dietary analysis in symptomatic patients with coeliac disease on a gluten-free diet: The role of trace amounts of gluten and non-gluten food intolerances

Background: Whereas many people with coeliac disease (CD) are asymptomatic when consuming a gluten-free diet (GFD),a proportion continues to experienc e symptoms. The reasons for this are unclear. Methods: Thirty-nine adult me mbers of The Coeliac Society of New South Wales, all of whom had persistent gastrointestinal symptoms despite adhering to a GFD, were evaluated. Dieta ry analysis indicated that 22 (56%) were consuming a GFD as defined by the WHO/FAO Coder Alimentarius (Codex-GFD), in which foods containing up to 0.3 % of protein from gluten-containing grains can be labelled as 'gluten free' . The remaining 17 were following a no detectable gluten diet (NDG)-GFD, as defined by Food Standards Australia. Ail subjects were required to follow a NDG-GFD during the study. Those in whom symptoms persisted after changing from a Codex-GFD and those who entered the study already on a NDG-GFD bega n an elimination diet followed by open and double-blind challenges to ident ify specific non-gluten food or food chemical intolerances. Results: Of 22 patients who switched to a NDG-GFD symptoms resolved in 5 (23%) and were re duced in 10 others (45%). Thirty-one subjects commenced the elimination die t. Symptomatic improvement was experienced in 24 (77%). Subsequent food or food chemical challenges resulted in a mean of five positive challenges per individual. Diarrhoea was the most commonly provoked symptom, followed by headache, nausea, and flatulence. Symptoms were especially provoked by amin e, salicylate and soy. Conclusion: The consumption of trace amounts of glut en, traditionally allowed in a Codex-GFD may be responsible for the continu ing symptoms seen in some patients with CD. Further investigation for non-g luten food intolerances should follow if symptoms persist after adherence t o a NDG-GFD.