What’s Really Behind IBS-D? Causes, Triggers, and Treatments (Part 1 of IBS-D series)

We map out a clear, practical way to understand IBS-D, from what it is, to how clinicians rule out the conditions that can look like it. With Dr. Anthony Lembo, we move from science to real-world next steps so you can feel more confident about diagnosis, treatment options, and hope for improvement. 

• How IBS-D is defined using stool form and pain patterns 
• When diarrhea needs more workup using alarm features 
• Common IBS-D mimickers including celiac disease, IBD, bile acid malabsorption, microscopic colitis, sucrase isomaltase deficiency and Giardia 
• What post-infectious IBS may change in the gut including immune activation, permeability, microbiome, and hypersensitivity 
• What the L-glutamine permeability study suggests and what remains unknown 
• How to approach it  a stepwise treatment IBS-D plan using lifestyle, loperamide, antispasmodics, neuromodulators, rifaximin, and other prescriptions 
• Why brain-gut behavioral therapy helps even without severe anxiety or depression 
• How we avoid the trap of endless “root cause” chasing with a confident diagnosis 

Rome V will include an update of the Rome Criteria (publication available around May 2026). 

This episode has been sponsored by Salix Pharmaceuticals. 

Follow us on social media, instagram @theguthealthpodcast, where we’d love for you to share your thoughts, questions, and experiences. 

References: 

Black CJ, Ford AC. An evidence-based update on the diagnosis and management of irritable bowel syndrome. Expert Rev Gastroenterol Hepatol. Published online January 21, 2025. doi:10.1080/17474124.2025.2455586

Marasco G, Cremon C, Barbaro MR, Stanghellini V, Barbara G. Journal of Clinical Gastroenterology Lectureship Dubai 2022 : Management of Irritable Bowel Syndrome With Diarrhea. J Clin Gastroenterol. 2024;58(3):221-231. Published 2024 Mar 1. doi:10.1097/MCG

Congenital Sucrase-Isomaltase Deficiency: What, When, and How?

Foley A, Halmos EP, Husein DM, et al. Adult sucrase-isomaltase deficiency masquerading as IBS. Gut. 2022;71(6):1237-1238. doi:10.1136/gutjnl-2021-326153

Learn more about Kate and Dr. Riehl:

Website: www.katescarlata.com and www.drriehl.com
Instagram: @katescarlata @drriehl and @theguthealthpodcast

Order Kate and Dr. Riehl's book, Mind Your Gut: The Science-Based, Whole-body Guide to Living Well with IBS.  

The information included in this podcast is not a substitute for professional medical advice, examination, diagnosis or treatment.  Always seek the advice of your physician or other qualified health care provider before starting any new treatment or making changes to existing treatment.