Patients with irritable bowel syndrome (IBS) are a heterogenous group, and many report symptoms triggered by diet: most commonly wheat/grains, certain vegetables, milk products, fatty foods, spicy foods, coffee, and alcohol.
A review published in The American Journal of Gastroenterology discusses the relationship between symptoms, diet, and microbiota in IBS. Authors summarize evidence on how diet and intestinal microbiota impact IBS symptoms. They also review reported interactions between diet and microbiota composition. They conclude that the microbial alterations found in IBS patients might cause or perpetuate the GI symptoms. The benefits of FODMAP restriction seem promising, but more studies are needed on how food triggers IBS symptoms.
Rajilic-Stojanovic M, et al. (2015) Intestinal microbiota and diet in IBS: Causes, consequences, or epiphenomena? American Journal of Gastroenterology doi:10.1038/ajg.2014.427
See here for a recent review exploring the pathophysiology of IBS.