The Thyroid (and Hormone) Fixer Podcast

Episode 613: IBS, Hashimoto’s, and the Thyroid–Gut Connection with Izabella Wentz

Host: Dr. Amie Hornaman
Guest: Izabella Wentz, PharmD (The Thyroid Pharmacist)
Date: March 17, 2026

Episode Overview

This episode explores the intricate connection between gut health—specifically IBS (Irritable Bowel Syndrome)—and thyroid autoimmunity (Hashimoto’s hypothyroidism). Dr. Amie Hornaman interviews Izabella Wentz about her new book on IBS, focusing on how gut dysfunction often precedes and drives autoimmune thyroid conditions. The conversation combines personal stories, clinical insights, and practical approaches, debunking myths about IBS and leaky gut while offering listeners useful strategies for real healing.

Key Discussion Points & Insights

1. The Gut–Thyroid–Autoimmunity Triangle

• Gut Health as a Root Cause:
  • Izabella describes how gut issues like IBS can be a precursor to the development of Hashimoto’s and other autoimmune disorders.
  • She shares a personal story: “I wish I had known that having IBS would put me at risk for autoimmunity later on in life... My hope is that women who have IBS can prevent a lifetime of various health conditions by treating their IBS.” (00:00)
  • The “three-legged stool” model of autoimmunity: genetics, a trigger (like stress or infection), and intestinal permeability (“leaky gut”) must all be present for autoimmunity to manifest. (07:10, 17:05)

2. What is IBS? How Is It Diagnosed and Why Does It Matter?

• Diagnosis is often clinical—based on symptoms like constipation, diarrhea, bloating—after other diseases are ruled out.
• “Underneath that [IBS] label is 20 different causes... 98% of [IBS-diagnosed patients] had some treatable cause.” (09:56)
• Conventional medicine offers only band-aid solutions (“eat more fiber”, “stress less”, “take a probiotic”) without addressing root causes. (09:56)
• “It still is a blow off... It’s still a dismissal of what that person is actually going through. And that’s a shame.” — Dr. Amie (12:06)

3. Izabella’s Personal IBS and Hashimoto’s Journey

• Stressful period in pharmacy school led to IBS symptoms, dismissed as “just stress” by doctors.
• Medication provided only temporary relief, with side effects; real healing didn’t come from conventional approaches. (13:32)
• Six years after IBS diagnosis, she developed Hashimoto’s: “It was actually that IBS diagnosis that helped me put together the whole path to remission, because we know gut health is such an important driver of autoimmunity.” (15:22)

4. Leaky Gut Explained: Prevalence, Testing, and Misconceptions

• Leaky Gut Defined: The intestine acts as a barrier; when it’s “leaky,” toxins and food particles enter the bloodstream, inflaming the immune system.
• Leaky gut is common in people with autoimmunity, but not universal; up to 50% may be asymptomatic, while others experience migraines, rashes, anxiety (20:51).
• Testing for leaky gut: Comprehensive stool tests (e.g. GI Map, Gut Zoomer) that measure zonulin levels, as well as organic acids for ammonia buildup. (21:39, 33:32)

5. Infections, Parasites, & IBS

• Blastocystis hominis: Found in ~70% of IBS patients; clearing this parasite can normalize thyroid antibodies and sometimes place Hashimoto’s in remission. (24:02)
• Not everyone should jump into parasite cleanses—targeted treatment after proper testing is crucial.
• “Sometimes when you’re throwing the whole kitchen sink at your body, you might not be doing yourself any favors or your liver any favors.” — Izabella (30:17)

6. Overdoing Gut Healing: The Dangers of Excess

• Over-supplementing with herbs or broad-spectrum parasite cleanses can be overwhelming, even harmful; individualized, evidence-based protocols are best. (30:17)
• Herbs like artemisia can be effective but are not always benign—potential liver toxicity, especially with prolonged use.

7. Digestion & Elimination: What’s Normal?

• “You should poop every day, maybe twice a day... The stools should be relatively soft, not too hard, not diarrhea.” (32:02)
• Constipation leads to estrogen recirculation, ammonia toxicity (manifesting as brain fog), and impaired detox.
• Low stomach acid, common in hypothyroid patients, impairs protein digestion: “Most people with hypothyroidism have either low levels of stomach acid or even no stomach acid.” (34:48)

8. The Stress–Gut Connection

• Chronic stress depletes secretory IgA (gut’s immune defense), increases gut permeability, and triggers flare-ups.
• “Adrenaline sends a signal to our microbiome to be more aggressive... Adrenaline is like rocket fuel for your opportunistic bacteria.” (41:01)
• Acute stress vs. chronic stress: Occasional nerves (“stage fright GI upset”) very different from the daily chronic depletion seen in overachievers (42:17).

9. Practical Protocols: Probiotics, Collagen, and More

• Probiotics: “I love probiotics for the right person... but if you have SIBO, certain probiotics can make your symptoms worse. Histamine intolerance (often due to parasites/mold) also changes what you should use.” (50:04)

  • Saccharomyces boulardii is often helpful, especially for diarrhea-dominant IBS.
  • Commercial/prophylactic doses may be insufficient to “move the needle” in serious gut dysfunction.

• Collagen and Bone Broth: Generally supportive of gut lining repair (glutamine, glycine), but watch for rare sensitivities or issues with oxalate metabolism. (52:36)

  • “If you have trouble with these, I would look into B6 deficiency because that helps us tolerate glutamate.” (53:54)

• Digestive Enzymes/ Betaine HCl: Key for those with low stomach acid and protein digestion issues—transformative for some hypothyroid patients. (34:23)

• Food Elimination: Gluten and dairy are the most common triggers for both Hashimoto’s and IBS; leafy greens and blueberries are frequent issues for IBS.

  • Focus on root causes—goal is not food avoidance forever but restoration of tolerance.
  • Processed food and additives (esp. artificial sweeteners like erythritol) are major gut disruptors. (54:08)

10. Memorable Quotes

• “There was a meme... that said, ‘I had 99 problems, but healing my gut solved 97 of them.’ And that’s my hope for people who pick up the book.” — Izabella (56:04)
• “Rest and digest—digest is in that phrase for a reason... Of course there’s a connection there.” — Dr. Amie Hornaman (43:30)

Timestamps for Important Segments

• 00:00 — Izabella’s wish: Understanding IBS-autoimmunity risk
• 07:10 — Exploring the gut–thyroid connection
• 09:56 — Problems with IBS diagnosis and treating root causes
• 13:32 — Izabella’s personal journey and IBS experience
• 17:05 — Unpacking leaky gut and the “three-legged stool” of autoimmunity
• 21:39 — Leaky gut testing (stool tests, zonulin)
• 24:02 — Parasites (Blastocystis hominis), IBS, Hashimoto’s remission
• 30:17 — Caution: Overdoing supplements and cleanses
• 32:02 — What is healthy digestion? Poop frequency and toxicity
• 34:48 — Low stomach acid and hypothyroidism
• 41:01 — Chronic stress, adrenaline, and gut microbiome
• 50:04 — Probiotics: Which to use, which to avoid
• 52:36 — Collagen, bone broth, and gut repair nuances
• 54:08 — Food elimination, processed foods, keto snacks
• 56:04 — Final hope: Healing the gut is life-changing

Notable Memorable Moments & Quotes

• “If we have optimal secretory IgA levels, we can actually fight a lot of infections on our own.” — Izabella Wentz (26:56)
• “Chronic stress is the burnout of the digestive system.” — Dr. Amie Hornaman paraphrasing Izabella (40:07)
• “You’re finally being heard. This is Thyroid Fixer Podcast, and this is where you rise.” — Dr. Amie Hornaman (00:26)
• “If you wake up with a flat stomach and you’re pregnant by the end of the day, your microbiome needs a little bit of love.” — Izabella (44:15)

Practical Takeaways

• Test, Don’t Guess: Get comprehensive stool tests, check specific markers (zonulin, secretory IgA), and look for root causes before jumping into protocols.
• Focus on Individualized, Targeted Approaches: Avoid shotgun “kitchen sink” supplementation or cleanses.
• Address Stress and Lifestyle: Chronic stress is a huge factor—rest and digest is literal!
• Begin with Basics: Daily, comfortable elimination is crucial for hormone and toxin balance; support digestive capacity (enzymes, Betaine HCl), avoid processed foods, and use supplements judiciously.
• Understand and Address Food Sensitivities but work to restore tolerance over time.

Resources

• Izabella Wentz’s Book: IBS: Finding and Treating the Root Cause of Irritable Bowel Syndrome
  • Available on Amazon, Barnes & Noble, and thyroidpharmacist.com/IBS (pre-order bonuses available)
• Learn More:
  • Dr. Amie Hornaman: dramiehornaman.com
  • Free resources and support on The Thyroid Fixer podcast and related support groups.

Closing Thought

As Izabella points out:
“You deserve to feel better. My book can help 98% of people figure out what’s causing their IBS and get the proper treatment so they can have optimal gut function and potentially get rid of a lot of other conditions.” (56:04)

For anyone suffering symptoms like fatigue, brain fog, weight gain, gut discomfort, or experiencing frustrating medical dismissal, this episode illuminates the deep gut–thyroid connection and offers hope—and a roadmap—to genuine, lasting healing.