Evolution of Medicine Podcast · Functional Forum

The Thyroid to IBS Journey

March 23, 2026·32 min·2 clips

Dr. Alessio Fasano’s three-legged stool links autoimmunity to genetics, a trigger, and intestinal permeability.

The opening pushes against a too-simple stress story. The guest agrees that stress can matter in IBS and other digestive problems, but she does not buy the idea that meditation and stress reduction solve every case. James Maskell sets the conversation in functional medicine, with Dr. Isabella Wentz returning as the thyroid pharmacist, now with an IBS book and a wider case for looking at what is actually driving symptoms. The practical question is pretty plain. When digestive symptoms keep coming back, the work cannot stop at calling them normal or telling someone to stress less and meditate. Gut infections give the episode one clear example. Wentz describes a case where SIBO testing was suggested, but the person did not have SIBO and instead had other gut infections. That changes the frame fast. IBS is treated here as more than a tidy label. It may connect with autoimmunity, chronic hives, thyroid issues, and other patterns. Wentz says IBS accounts for 12% of primary care visits and may affect 25 to 45 million people in the United States, which is exactly why it can get waved off. Common does not mean harmless. The episode keeps coming back to trajectory. Wentz describes women moving from IBS to fertility issues, then thyroid or autoimmune diagnoses, with anxiety sometimes showing up earlier in the story. The tone is not alarmist. It is a clinician-facing nudge to catch digestive dysfunction earlier and ask better questions. Food, medication side effects, psychosocial stress, infections, and other physical causes all stay on the table until a fuller workup narrows things down. Maskell closes by tying that kind of thinking back to functional medicine training.

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