The role of gluten as a cause of gastrointestinal symptoms and fatigue in patients who do not have coeliac disease

Arm 1: Whole wheat-gluten (16 grams of commercial gluten per day); and Arm 2: Whole wheat-gluten (2 grams of commercial gluten per day ). The study is a randomised, placebo-controlled, double-blinded cross-over study design of 9 weeks duration (including a two-week run-in period at the start), where eligible volunteers will be randomly allocated to receive one of the three treatment arms for 1 week, followed by a washout period of at least 2-weeks (or until symptoms induced during the previous dietary challenge have resolved), before crossing over to the next diet. Each volunteer will undertake all 3 treatment arms. All food will be provided where the gluten will be administered across the day in different meals (all baseline meals will be gluten-free and low in poorly absorbed fermentable carbohydrates).