Date of Award

Summer 6-24-2022

Document Type


Degree Name

Doctor of Medical Science (DMSc)


Department of Physician Assistant Medicine

First Advisor

Justin M. Gambini, DMSc, PA-C, DFAAPA



Irritable bowel syndrome (IBS) is a very common chronic functional gastrointestinal (GI) disease that is characterized by abdominal pain in association with defecation and change in bowel habits.1 The condition has a multifactorial and incompletely understood pathophysiology, including altered brain-gut interactions, microbiome changes, differed GI motility, psychological factors, and food hypersensitivity.2 With the heterogenicity of the disorder, there is no standardized treatment for IBS, leading its therapy to rely on symptomatic treatments.2 The influence of dietary triggers on the generation of IBS symptoms is well-known and includes different mechanisms including immune activation, mast cell inflammation, and luminal distention.2 Studies show that 50% of patients with IBS have postprandial exacerbations of symptoms within 90 minutes of eating with the prevalence of food intolerance being as high as 70%.3 More specifically, Fermentable Oligo-, Di-, and Mono-saccharides And Polyols (FODMAPs) have been recognized as triggers to IBS symptoms, as they ultimately lead to increased gas production as a consequence of food fermentation.1 Therapeutic gains offered by medications are only 8-20% more than that of placebo use, thereby improving the conditions of less than half of patients.3 Given the limitations of drug therapy, the long course of IBS, and the role of food in symptom development, diet and lifestyle play an essential role in managing IBS.2,3 Unfortunately, there is currently little high-quality evidence regarding a dietary approach.2 Nevertheless, many different approaches have been suggested including the low-FODMAP diet (LFD), gluten-free diet (GFD), wheat-free diet (WFD), and lactose-free diet, with the first two mentioned diets being the most suggested.2 This article will focus on comparing the diets used for those with IBS and discuss how providers today can best implement these diets in current practice.