You might already know that the two most common types of thyroid dysfunction, Hashimoto’s and Graves’, are caused by autoimmune disease, a condition in which your body confuses your own tissues with outside invaders and begins attacking itself. But what causes the autoimmunity, and how does it lead to thyroid disease? The answer is multi-part, but as I explain in my book, The Thyroid Connection, it all begins in the gut, because the gut is the gateway to health. In this article, we will uncover the ways in which a damaged gut sets off a chain reaction that leads to both autoimmune and non-autoimmune thyroid disease.


Healthy Gut or Leaky Gut?

Thanks to the pioneering work of Dr. Alessio Fasano, we now know the mechanics that cause a leaky gut, and that it is one of the primary triggers for all autoimmune disease,1 including autoimmune thyroid disease. As you might guess by its name, leaky gut occurs when your gut (specifically your small intestine) becomes too permeable, allowing particles to leak from your digestive tract and travel freely through your bloodstream.

Gluten is one of the main causes of leaky gut in people that I see with thyroid issues and autoimmune diseases, and not just among Celiac patients, but in anyone with gluten sensitivity. When anyone with gluten sensitivity eats gluten-containing food, the gluten proteins make their way through the stomach and arrive at the small intestine, where the body responds by producing zonulin, a chemical that signals the tight junctions of the intestinal walls to open up, creating permeability. Leaky gut can also be caused or exacerbated by gut infections such as Candida overgrowth, medications like antibiotics or birth control pills, and stress.

Now that your permeable small intestine has allowed toxins, microbes, and partially digested food to leak into your bloodstream, your immune system goes on high alert to neutralize all of these threats. But, because your gut is still leaky, the threats just keep on coming, putting your body in a state of chronic inflammation and putting you on the path to develop an autoimmune disease as your immune system becomes so stressed that it begins attacking your own tissue by mistake. Unfortunately, the gluten that caused your gut to become leaky also makes it more likely that you will develop thyroid disease, due to its structural similarity to your thyroid tissue.

Molecular Mimicry, A Case of Mistaken Identity

Every time your body is exposed to a dangerous outside invader, your immune system memorizes its structure, specifically its protein sequence, so that it can develop the perfect defense to that pathogen and recognize it in the future.

But, the immune system’s recognition system isn’t perfect; as long as a molecule’s structure and protein sequences are similar enough, the immune system can be fooled into attacking look-a-like molecules that are actually your body’s tissue, causing autoimmune disease. Unfortunately for the thyroid, it has two common doppelgangers that put it at risk for rogue autoimmune attacks: gluten and casein (a protein found in dairy), both of which are likely rampant in your bloodstream now, thanks to your leaky gut.

How Molecular Mimicry Happens, leading to Autoimmunity – Gluten From Breads and Casein from Dairy Foods – Infographic – Amy Myers MD®How Molecular Mimicry Happens, leading to Autoimmunity - Gluten From Breads and Casein from Dairy Foods - Infographic - Amy Myers MD® Molecular Mimicry Happens, leading to Autoimmunity – Infographic – Amy Myers MD®

It could be pulled straight from a scene in a classic old movie, the thyroid shouts indignantly, “I didn’t do anything, I swear! You’ve got the wrong guy!” and the antibodies cynically retort, “Sure buddy, sure,” before binding to your thyroid tissue to neutralize the “threat.” In the case of autoimmune hypothyroidism (Hashimoto’s disease), your immune system’s attacks diminish thyroid functionality, so your metabolic processes slow down. In autoimmune hyperthyroidism (Graves’ disease), the antibodies act like Thyroid Stimulating Hormone, causing your thyroid to overproduce its hormones and sending your metabolism into overdrive.

Even in patients who have non-autoimmune thyroid disease, the molecular mimicry phenomenon still impacts thyroid function, which is why I recommend that all of my patients with thyroid disease remove gluten from their diets, even if they are not autoimmune.

Although gluten and casein are the most common hypothesized causes of molecular mimicry-induced autoimmune thyroid disease, the bacteria Yersinia enterocolitica, which makes its way to the gut via contaminated food or water, has been documented by researchers to cause Grave’s disease due to its cross-reactivity with the Thyroid Stimulating Hormone receptor.

How to Prevent Autoimmune Thyroid Caused by Leaky Gut and Molecular Mimicry

Although a gluten-heavy diet and leaky gut can set you on a dangerous path towards autoimmune thyroid disease, their negative effects can be diminished and even reversed by implementing the first two pillars of The Myers Way® – Pillar I: Heal Your Gut, and Pillar II: Remove Gluten, Grains, and Legumes.

In Pillar I, I recommend a four-step approach to repairing the gut that allows the junctions of your small intestine to close back up, replenishes your good gut bacteria, and strengthens your gut’s immune system. During this stage I recommend taking Leaky Gut Revive™ to strengthen your mucosal cells and heal your leaky gut. Your can also support your gut with bone broth, which heals the digestive tract and reduces inflammation, with my recipe, Gut Healing Bone Broth with Organic Greens. In Pillar II, you will remove gluten to prevent further intestinal damage, inflammation, and cross-reactivity with your thyroid, but you will also remove grains and legumes, which are cross-reactive with gluten and can pose many of the same health risks.

For more information on the gut-thyroid connection, check out my interview with Josh Axe on how diet and gut health can affect your thyroid.