The effect of a controlled gluten challenge in a group of patients with suspected non-coeliac gluten sensitivity: A randomized, double-blind placebo-controlled challenge.

Abstract

Non-coeliac gluten-sensitivity (NCGS) has been proposed as a new entity with unknown prevalence and mechanisms, and there is a need for a standardized procedure to confirm the diagnosis. The objective of this study was to characterize the response to an oral gluten-challenge in patients with a symptom-relief when following a gluten free-diet (GFD). Twenty patients (14F/6M, age range: 21-62years) with suspected NCGS, without coeliac disease and wheat-allergy, were included while on a gluten-free diet. All patients went through four periods of double-blinded provocation, two with gluten and two with placebo in randomized order. They consumed two muffins a day (11/0g gluten) for 4days, followed by a 3-day wash-out. Gastrointestinal symptoms were recorded with questionnaires at baseline and after each provocation. We also investigated whether patients were able to correctly identify periods with gluten-exposure. Collectively the whole group reported the most severe symptoms after placebo (P=.012). Four out of twenty patients correctly identified the two periods when they received gluten, hence were diagnosed with NCGS. The diagnosed-group tended to show higher symptom scores than the not-diagnosed group both at baseline, after gluten exposure and after placebo, but no clear difference was seen between provocation with gluten and placebo. The not-diagnosed group showed more severe symptoms with placebo than with gluten (P=.029). The present study showed that the majority of patients with suspected NCGS are not able to identify when challenged with gluten in a double-blind placebo-controlled food challenge, indicating that gluten is not the cause of their symptoms.