The popularity of bread is declining and a gluten-free diet trending. People who stop eating bread and other gluten containing foodstuffs claim to have less abdominal pain, even though they were not diagnosed as gluten intolerant. Wageningen University & Research and scientific and commercial partners investigate the relation between wheat and the irritable bowel syndrome. They examine modern bread wheat, spelt and emmer (an older type of wheat), and compare yeast and sourdough preparations. With human intervention studies, the effect of wheat and wheat products on metabolism, gastro-intestinal function, symptoms and subjective well-being will be analysed.