Gluten, the major protein of wheat, has been established as the causative agent in the development of coeliac disease, characterised by small intestinal injury and immunological activation. Gluten has also been implicated as a causal factor in the development of chronic functional gastrointestinal symptoms similar to those classified as irritable bowel syndrome (IBS).
Twenty-two subjects (24–62 years, five male) with irritable bowel syndrome who had coeliac disease excluded but were symptomatically controlled on a gluten free diet (GFD), undertook a double-blind cross-over study. Participants randomly received one of three dietary challenges for 3 days, followed by a minimum 3-day washout before crossing over to the next diet. Challenge gluten-free food was supplemented with gluten (16 g/day), whey (16 g/day) or not supplemented (placebo).
Gluten ingestion was associated with higher overall state depression scores compared to placebo [P = 0.010].
Short-term exposure to gluten specifically induced current feelings of depression. Such findings might explain why patients with non-coeliac gluten sensitivity feel better on a gluten-free diet despite the continuation of gastrointestinal symptoms.
Aliment Pharmacol Ther 2014; 39: 1104–1112.