Irritable bowel syndrome (IBS) is a heterogenous, common gastrointestinal disorder characterized by chronic abdominal pain and altered bowel habits. Many IBS patients report symptom relief on a gluten-free diet (GFD), but it is uncertain whether gluten is the true culprit. The gluten-containing grains wheat, rye, and barley all contain amylase-trypsin inhibitors (ATIs), and a GFD is virtually ATI-free.~This double-blinded crossover randomized controlled trial aims to determine which IBS patients are affected by pure gluten and which are affected by gluten combined with ATIs. IBS patients who respond to and have been on a GFD for 3+ weeks will be randomized to receive a dietary challenge of muesli bars containing either 1) pure gluten, 2) non-purified gluten (containing ATIs), 3) or nocebo for a week followed by a 14 day washout. This will be repeated until all participants have had each dietary challenge.~The study will evaluate the effects and potential mechanisms of purified and non-purified gluten on intestinal and extra-intestinal symptoms in IBS. It is likely that some IBS patients respond to gluten, while others respond to gluten combined with ATIs. Thus, this project may lead to better diagnosis and individualized dietary treatments for IBS.
This crossover randomized controlled trial will evaluate the effects of gluten and gluten combined with amylase-trypsin inhibitors (ATIs) on inducing intestinal and extra-intestinal symptoms in irritable bowel syndrome (IBS) patients. All participants will be put on a gluten-free diet and then challenged with muesli bars containing either purified gluten, gluten with ATIs, or nocebo.