A number of studies have found IBS may be due to carbohydrate maldigestion and intolerance. It can cause abdominal cramps and bloating. A low Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAP) diet such as avoiding wheat, high lactose dairy, garlic, onions and certain fruit, may reduce abdominal symptoms and improve quality of life compared with a traditional IBS diet.
Varjú P, Farkas N, Hegyi P, Garami A, Szabó I, Illés A, Solymár M, Vincze Á, Balaskó M, Pár G, Bajor J, Szűcs Á, Huszár O, Pécsi D, Czimmer J. Low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet improves symptoms in adults suffering from irritable bowel syndrome (IBS) compared to standard IBS diet: A meta-analysis of clinical studies. PLoS One. 2017 Aug 14;12(8):e0182942. doi: 10.1371/journal.pone.0182942. eCollection 2017. https://www.ncbi.nlm.nih.gov/pubmed/28806407
Diet Low in FODMAPs Reduces Symptoms in Patients with Irritable Bowel Syndrome and Probiotic Restores Bifidobacterium Species: a Randomized Controlled Trial. Gastroenterology. 2017 Jun 15. pii: S0016-5085(17)35744-X. doi: 10.1053/j.gastro.2017.06.010. https://www.ncbi.nlm.nih.gov/pubmed/28625832