[Fiber, food intolerances, FODMAPs, gluten and functional gastrointestinal disorders--update 2014].

The controversial effects of dietary fiber on symptoms in functional gastrointestinal disorders are summarized. Studies concerning adverse reaction to foods are mentioned and the possible role of food allergy and food intolerances, especially pseudoallergic reactions to biogenes amines, in symptom provocation is discussed. The known effects of lactose deficiency and fructose malabsorption are reviewed. The FODMAP concept (fermentable oligo-, di-, monosaccharides and polyols) is presented in more detail and recent studies on pathophysiological effects of FODMAP constituents and of therapeutic effects of a low FODMAP diet on symptoms in patients with irritable bowel syndrome are discussed. Finally, studies on the new disorder non-celiac gluten sensitivity (NCGS) are summarized and the state of the discussion whether wheat intolerance is due to gluten or the grains is given.