MCAS is one of those diagnoses that can make it feel like your body is telling a dozen stories at once—and no one is listening. If you're experiencing GI symptoms alongside flushing, hives, brain fog, fatigue, palpitations, medication sensitivities, or a persistent "fight-or-flight" feeling, this episode is designed to help connect the dots without oversimplifying your experience. In this episode, we sit down with gastroenterologist Dr. Zachary Spiritos to unpack mast cell activation syndrome (MCAS) and explore the connections between immune activation, the gut-brain axis, and symptoms that can affect nearly every system in the body. We discuss why patients are often dismissed, how stress and hormonal changes can amplify symptoms, and what a realistic, stepwise treatment approach looks like when the evidence base is still evolving. In this episode, we discuss: • What mast cells do and why MCAS can affect multiple organ systems • Why MCAS is often missed in siloed medical care and mislabeled as anxiety • Barrier dysfunction, environmental triggers, and intestinal permeability as a useful framework • Histamine as one mediator among many and why antihistamines are not a perfect treatment for all • Links between MCAS, IBS, visceral hypersensitivity, dysautonomia, and POTS • Hypermobility, pelvic floor dysfunction, and neck tension as common clinical clues • Treatment principles including start low and go slow, informed consent, and layered individualized plans • Dietary approaches patients commonly explore, including low-histamine, low-FODMAP, and gluten-free patterns • Hormonal influences across the menstrual cycle and during perimenopause • The role of sleep, nervous system regulation, and stress reduction in decreasing symptom reactivity If you've ever felt like your symptoms don't fit neatly into a single diagnosis, this episode will help you make sense of the bigger picture and explore what healing can look like when the gut, immune system, and nervous system are all part of the conversation. References: Ford AC, Staudacher HM, Talley NJ. Postprandial symptoms in disorders of gut-brain interaction and their potential as a treatment target. Gut. 2024;73(7):1199-1211. Published 2024 Jun 6. doi:10.1136/gutjnl-2023-331833 Walker MM, Warwick A, Ung C, Talley NJ. The role of eosinophils and mast cells in intestinal functional disease. Curr Gastroenterol Rep. 2011;13(4):323-330. doi:10.1007/s11894-011-0197-5 Pasricha PJ, Talley NJ. Functional Dyspepsia. N Engl J Med. 2026;394(2):166-176. doi:10.1056/NEJMcp2501860 Find Dr. Spiritos on IG @drzacspiritos So please like and subscribe and share the gut health podcast. Don't forget to subscribe, rate, and leave us a comment. 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.
