Does gluten cause gastrointestinal symptoms in subjects without coeliac disease?

Aim: To determine the evidence for the effect of gluten ingestion on gastrointestinal symptoms, intestinal permeability and other indices of small intestinal injury in non-coeliac, gluten intolerant individuals.

Methods: A literature review was performed searching for interventional studies that addressed the issue.

Results: One unblinded study that identified symptomatic response to gluten did not effectively exclude patients with coeliac disease, since many had intraepithelial lymphocytosis. A double-blinded, randomised, placebo-controlled rechallenge trial was recently reported in patients in whom coeliac disease had been excluded by either normal duodenal histology on a gluten containing diet, or absence of the HLA DQ2 or DQ8 haplotype (56%). Participants were randomly assigned to receive either 16 g/day carbohydrate-free gluten or placebo for six weeks. Participants were enrolled if they had gastrointestinal symptoms that had improved on a GFD and had been on a gluten free diet for at least 6 weeks prior to enrollment. 19 received gluten and 15 received placebo. Change between baseline and final weeks were greater for patients receiving gluten in overall symptom severity compared with those receiving placebo (p=0.047). and were worse with gluten within one week for pain (p=0.016), bloating (p=0.031), satisfaction with stool consistency (p=0.024), and tiredness (p=0.001). Mechanisms for symptom induction were not identified.

Conclusions: Non-coeliac gluten intolerance does exist. Future studies need to identify issues of the dose of gluten needed and mechanisms of action.