Gluten and (Extra-)Intestinal Symptoms in NCGS

The goal of this randomized, double-blind, placebo-controlled study is to investigate the effect of expectancy related to gluten consumption versus actual gluten intake on overall GI symptoms in individuals with non-coeliac gluten sensitivity (NCGS) The main questions it aims to answer are: * what is the effect of consumer expectancy, related to either gluten-containing or gluten-free oat bread, on short-term (within 8 hours) overall GI symptoms in individuals with NCGS? * what is the effect of actual gluten intake on short-term (within 8 hours) overall GI symptoms in individuals with NCGS Participants will be randomised into four groups: 1. Participants with the expectation of receiving gluten-containing bread and actually receiving gluten-containing oat bread during the test day. (E+ G+) 2. Participants with the expectation of receiving gluten-containing bread, but actually receiving gluten-free oat bread during the test day. (E+ G-) 3. Participants with the expectation of receiving gluten-free bread but actually receiving gluten-containing oat bread during the test day. (E- G+) 4. Participants with the expectation of receiving gluten-free bread and actually receiving gluten-free oat bread during the test day. (E- G-)