Podcast Summary: "You Are Not Broken" — Ep. 353: Thyroid, Gut and More

Host: Dr. Kelly Casperson, MD
Guest: Dr. Christine Marin, Board-Certified Family & Functional Medicine Physician
Date: January 11, 2026

Overview

This episode takes a deep dive into the often-overlooked relationship between thyroid health, the gut, hormones, and how these factors intersect during midlife, particularly for women. Host Dr. Kelly Casperson and guest Dr. Christine Marin unpack why thyroid disorders (especially Hashimoto’s) are underdiagnosed, how gut health is central to autoimmune issues, the complexity of lab testing, the role of functional medicine, and the vital importance of boundaries and stress management for healing. The conversation is layered with both personal stories and science, and full of actionable insights for listeners navigating fatigue, gut issues, perimenopause, and health confusion.

Key Discussion Points & Insights

The Thyroid in the Context of Midlife

• Neglected Topic: Despite its prevalence, thyroid health—especially in relation to perimenopause and midlife—is often excluded from menopause medicine.

  “Thyroid is an ignored piece sometimes in the menopause conversation. A lot of women don't know about it...a lot of people practicing menopause medicine often don’t address thyroid function.” — Dr. Marin [01:03]

• Conventional vs. Functional Lens: Dr. Marin brings both perspectives:

  • Conventional medicine focuses on lab reference ranges ("normal"), but may miss "optimal function".
  • Functional medicine considers broader systemic influences; thyroid function is "more than a number".

• Hashimoto’s Prevalence:

  • Most common cause of hypothyroidism in American women.
  • Often undiagnosed due to nonspecific symptoms and incomplete lab work-ups.

Lab Testing & Diagnosis

• Lab Tests: What’s Checked vs. What’s Needed

  • Most women only get TSH (thyroid-stimulating hormone) checked.
  • A full thyroid panel should include:
    • TSH
    • Free T4
    • Free T3 ("the gas" for metabolism)
    • Reverse T3 ("the brakes")
    • Thyroid peroxidase (TPO) & thyroglobulin (TG) antibodies.
  • Many providers under-order these labs, contributing to underdiagnosis.

  “Normal doesn’t mean optimal.” — Dr. Casperson [02:37]

• Reference Range Problems:

  • Normal lab ranges can be too broad; ‘normal’ may mean symptomatic for many women.
  • Example: TSH <2.5 is ideal for conception, but this isn’t flagged as abnormal by most labs.

  “There's a difference between normal range and optimal function.” — Dr. Marin [01:03]

Understanding the Thyroid’s Role

• Thyroid Location & Function:

  • Butterfly-shaped gland in the throat.
  • Regulates global body processes: metabolism, digestion, mood, sleep, skin, hair.

• Symptoms of Hypothyroidism:

  • Fatigue, constipation, brain fog, dry skin, hair loss (including outer eyebrow), weight changes, menstrual irregularities.

• Incidence & Underdiagnosis:

  • 1 in 8 women in midlife have a thyroid disorder, likely undercounted due to lack of screening.

Hashimoto’s Disease: Autoimmune Roots

• What happens with Hashimoto’s?

  • Body develops antibodies against the thyroid: TPO & TG antibodies.
  • Can smolder for years with vague symptoms before labs show hypothyroidism.
  • Autoimmune destruction may follow a flare-up (sometimes with short-lived hyperthyroid symptoms) before settling into hypothyroidism.

• Conventional vs. Functional Approaches:

  • Conventional: Medicate if needed, otherwise “watch and wait”.
  • Functional: Intervene early to reduce inflammation, focusing especially on gut health.

• Early Detection:

  “Is it possible you can have elevated antibodies but still have normal function?...That's the big deal.” — Dr. Casperson & Dr. Marin [14:15–14:29]

Gut Health & Autoimmunity

Gut-Thyroid Connection

• Gut Focus in Functional Medicine:

  • Major contributors to autoimmune thyroid illness:
    • Genetics (“load the gun”)
    • Environmental triggers (stress, hormonal changes, pregnancy, menopause)
    • Intestinal permeability (“leaky gut”)
  • Leaky gut allows immune stimulation and inflammation.

  "If you have autoimmune disease, you probably have some underlying gut issue." — Dr. Marin [57:19]

• SIBO (Small Intestinal Bacterial Overgrowth):

  • Over half of women with Hashimoto’s have SIBO.
  • SIBO symptoms: Bloating, belching, gas, constipation/diarrhea (depending on gas type).
  • Causes include: low stomach acid, disruption of gut motility, dental bacteria, post-infectious complications, and chronic stress disrupting the "migrating motor complex".

• How to test for SIBO?

  • Breath tests (e.g., TrioSmart, AeroSmart Diagnostics).

  “There’s a huge correlation between SIBO and autoimmune thyroid disease.” — Dr. Marin [16:54]

Food Sensitivities, Leaky Gut, and Testing

• Food Sensitivity Panels:

  • Can light up due to leaky gut, but are often misleading and used (or misused) in both conventional and functional medicine.
  • Removing too many foods = worsens gut health long-term; restricts diversity.

  “If you have a food sensitivity panel and everything lights up, you have leaky gut.” — Dr. Marin [26:46]

• Alcohol = Gut Enemy:

  • Alcohol is a major driver of gut permeability.

• Testing for Leaky Gut:

  • Zonulin: a stool (occasionally blood) protein marker.
  • High zonulin = increased gut permeability.

• Estradiol’s Protective Role:

  • Improves tight gut junctions; HRT may help reduce leaky gut in menopausal women.

Healing Beyond Labs: Stress, Boundaries, and Embodiment

The Role of Stress

• Stress is a Major Trigger:

  • High stress (emotional, chronic) is often the reason thyroid function begins to drop—“the body is responding to its environment.”
  • Healing requires both psychological and physiological intervention.

  “You can’t heal your physiology without healing your psychology.” — Dr. Marin [32:59]

• Boundaries:

  • The gut is a physical boundary; emotional boundaries are equally vital. Women are often culturally conditioned to lack boundaries, to their detriment.
  • Suppressed emotions (anger, especially) are common in women with autoimmune issues.

  “Women are culturally conditioned not to have boundaries in many cases.” — Dr. Marin [32:59]
  “Hashimoto’s...tendency is [to be] swallowing something. What aren’t you saying out loud?” — Dr. Marin [33:14]

Embodiment & The Path to Healing

• Personal Story Highlight:

  • Dr. Marin shares her complicated health journey; only after addressing psychological boundaries, embodiment, and internal dialogue did her physical health transform.

    “So much of this is about learning to show up for yourself, setting boundaries.” — Dr. Marin [39:04]

• Embodiment Defined:

  • Many high-achieving women are disconnected from their bodies, suppressing both needs and sensations.
  • Healing requires reconnecting to feelings, personal needs, and intuition.

Thyroid, Hormones & the Gut in “Functional” Healing

Can You "Cure" Thyroid Issues?

• Is Hypothyroidism Reversible?

  • Hashimoto’s: Addressing underlying inflammation and leaky gut can reduce antibodies and improve function, but years of destruction may require lifelong hormone support.
  • Subclinical cases: Some women can come off thyroid meds with improved gut, hormone, and immune health.
  • Estradiol (HRT) improves hormone receptor sensitivity and gut diversity, potentially aiding thyroid function.

• Hormones & the Gut:

  • Declining estradiol in perimenopause reduces gut microbiome diversity, raising inflammation and autoimmune risk.
  • The "microgenderome": After age 40, women’s gut microbiome begins to resemble men’s, which is less diverse and associated with increased health risks.

• Estrobolome:

  • Gut bacteria metabolize estrogen—a critical factor for both hormone balance and cancer risk.

  “If you’re not pooping out your estrogen, you’re going to have a problem.” — Dr. Marin [56:15]

HRT Formulations & Gut Effects

• Oral vs. Transdermal Estradiol:

  • Oral estrogen shown in small studies to improve gut diversity; but both oral and transdermal likely benefit the gut.

  “Clinically, I see patients…whose gut got a lot better after starting HRT, even transdermal.” — Dr. Marin [50:07]

• Progesterone and Constipation:

  • Some women experience constipation on higher doses of oral micronized progesterone. Decreasing dose or adding magnesium citrate (carefully) may help.

Practical Takeaways

When to Investigate Your Gut & Thyroid

• Red Flags:

  • Persistent digestive issues: bloating, gas, stool changes, cramping, abdominal pain, food sensitivities.
  • Autoimmune disease, especially with vague symptoms.
  • If symptomatic, don’t ignore — pursue comprehensive evaluation and, if needed, seek a functional medicine approach.

• Where to Start for Gut/Autoimmunity:

  • Remove gut infections (SIBO, Candida)
  • Replace digestive enzymes if lacking
  • Avoid alcohol, processed food, and antibiotics
  • Eat diverse, fiber-rich real food; increase plant diversity
  • Prioritize stress reduction and boundaries

  “Avoid the things that wreck your gut.” — Dr. Marin [57:23]

• Psychological Healing is Foundational:

  • Embodiment, boundaries, and self-care are as crucial as labs and supplements.

On Navigating Confusion & Avoiding Overwhelm

• Testing:
  • Not everyone needs extensive gut panels, but don’t ignore persistent digestive or autoimmune symptoms.
• Practitioners:
  • Be aware of training differences among “functional medicine” providers.
• Balance:
  • Don’t get stuck eliminating more and more foods; the goal is to increase tolerance and diversity through healing.

Notable Quotes & Memorable Moments

• "Normal doesn’t mean optimal."
  — Dr. Casperson [02:37]

• "There's a difference between normal range and optimal function."
  — Dr. Marin [01:03]

• "You can't heal your physiology without healing your psychology."
  — Dr. Marin [32:59]

• "Our bodies don't hate us, our bodies love us, our body’s here to protect us."
  — Dr. Marin [10:03]

• "Hashimoto’s is an autoimmune condition...two separate issues. There's an autoimmune condition that causes low thyroid function over time.”
  — Dr. Marin [12:18]

• "Your gut is a boundary. Those boundaries get compromised. We get leaky gut, we get immune dysregulation. In our emotional psychological world, boundaries are really critical."
  — Dr. Marin [32:59]

• "The most important piece…is that, wow, you're reacting to a lot of foods. That tells me that's basically a diagnosis of leaky gut."
  — Dr. Marin [27:26]

• "Hormones influence gut health, gut microbiome influence immune system...Everything does influence it, including the environment and your relationships and the air...”
  — Dr. Casperson [48:40]

Timestamps for Key Segments

• [01:03] — Thyroid’s role in menopause, midlife, and functional vs. conventional approaches
• [02:37–05:15] — The pitfalls of lab reference ranges; what labs to order for thyroid
• [09:10] — Prevalence and underdiagnosis of thyroid disorders in women
• [11:43] — How stress and environment influence thyroid health
• [12:11] — Deep dive: Hashimoto’s as an autoimmune disorder
• [14:29] — Why early detection of antibodies matters, and how functional medicine responds
• [16:47] — Gut health, SIBO, and their connection to autoimmune thyroid
• [25:24] — The complications of food sensitivity testing
• [32:59] — The importance of psychological boundaries; psychosomatic roots of illness
• [34:40–36:23] — Dr. Marin’s personal story of health crisis and healing
• [39:04] — Techniques for building better psychological and physical health (embodiment, self-care)
• [43:39] — Is thyroid dysfunction reversible? The evolving science, role of HRT
• [46:03] — Gut microbiome, menopause, and autoimmunity: how it all ties together
• [50:07–50:51] — The effect of oral vs. transdermal estradiol on gut health
• [56:15] — The estrobolome and estrogen metabolism
• [57:19] — Wrapping up: when to suspect gut issues and what to do

Resources & Where to Find the Guest

• Dr. Christine Marin’s website & socials: drchristinemarin.com | [Instagram/Facebook: @drchristinemarin]
• Licensed in Colorado, Michigan, Texas

Final Takeaway

The thyroid, gut, hormones, and mind are intimately linked—particularly for women in midlife. If you have ongoing digestive, hormonal, or unexplained symptoms, don’t settle for “normal” labs or superficial answers. Healing is both physiological and psychological—and your intuition, boundaries, and self-respect matter as much as your hormone and antibody levels. Seek comprehensive, integrative support. Remember: you are not broken.