How Faulty Digestion Can Wreck Your Thyroid

thyroidIn my work with clients, I always begin with a comprehensive health assessment form and one area that gets checked off frequently is hypothyroidism. While many individuals, particularly women, have been clinically diagnosed with low thyroid function, others suspect it because of challenges with weight gain, thinning hair, sleep difficulties, and a whole host of issues that fall under the broad range of symptoms associated with thyroid dysfunction.

Hypothyroidism is an health condition that is growing year by year: An estimated 20 million Americans have some form of thyroid disease; these include hypothyroidism, autoimmune thyroid (Hashimoto's disease & Grave's disease), thyroiditis, and hyperthyroidism. Up to 60 percent of these people are unaware of their condition. One in eight women will develop a thyroid disorder during her lifetime. Synthroid (Levothyroxine), a synthetic form of thyroid hormone, is the 4th highest selling drug in the U.S. and 13 of the top 50 selling drugs are either directly or indirectly related to hypothyroidism.

While the root causes of thyroid dysfunction are varied, the focus of this 2-part article is to emphasize the role that digestion plays in thyroid health. In part 2, we'll dive deeper into the topic of micronutrient deficiencies.

The Gut - Where It All Begins

Our guts are the epicenter where health conditions can emerge due to the function of our digestive tracts in absorption, assimilation, and transportation of nutrients to our entire body. In addition to the important role of “letting things in”, our GI tracts are also tasked with eliminating unnecessary waste and infectious agents. The gut is the gatekeeper – allowing vitamins, minerals, and other nutrients into our bloodstream while keeping pathogens, antigens, and other invaders out; that is, if everything is working properly. When the intestinal lining of our digestive tracts becomes compromised either by damage from poor nutrition, stress, medications, and/or other toxins, then tight junctions between cells loosen and "the gate cracks opens", giving way to foreign substances (deemed “intestinal permeability” in the medical literature). Fortunately we have our immune systems to help ward off these invaders that may slip through; unfortunately, the majority of our immune system is housed in the gut! Over 80% of our immune cells are manufactured in our GI tracts. A compromised gut equals a compromised immune system. In addition to a poorly operating immune system, these foreign substances can also influence the health of various cells, glands, and tissues, including that of the thyroid gland, in another way: molecular mimicry.

Molecular Mimicry

Here is how our immune systems are supposed to work:

  1. An invader (pathogen, antigen, toxin, etc.) enters the body
  2. Our immune system (cytokines, macrophages, secretory immunoglobulin and other immune regulatory cells) mounts a defense to neutralize and eliminate the foreign particles
  3. The immune response ceases once all foreign substances are dealt with appropriately

Molecular mimicry is a unique situation which occurs when our immune system mistakes one of our very own cells with the molecules of a foreign substance. These cells can be related to tissues, organs, cells, and glands - such as the thyroid.

This is the case with autoimmune thyroid conditions (AITD) with the invader/culprit being gluten. Several studies show a strong link between AITD (both Hashimoto’s and Graves’) and gluten intolerance (1, 2, 3, 4, 5). The molecular structure of gliadin, the protein portion of gluten, closely resembles that of the thyroid gland. When the intestinal lining is breached (to learn how the gut becomes permeable or "leaks" check out this episode of the Digestive Detective Radio show here), an individual with a propensity towards gluten intolerance (by some estimates up to 35% of the population)  will mount an immune defense, but the hyper-reaction from the immune cells paired with the molecular mimicry that occur triggers the body to also attack and damage the thyroid. Thyroid numbers may appear "normal" on lab results but those numbers are often skewed and do not give a complete picture of thyroid function; they also do not account for the damage being done slowly over time by such mechanisms as molecular mimicry. The unfortunate outcome is that many patients then leave their doctors office with a "clean bill of health" and a recommendation to "eat some whole grains." The gluten - thyroid damage continues. This overactive immune response and the presence of these foreign invaders also trigger a more subtle effect: stress.

Stress and the Adrenal-Thyroid Connection

Factors such as the pathogens, antigens, toxins, and other foreign substances we've already discussed all serve to create a stress response in the body. Further exacerbated by the breakdown in the barrier of the mucosal gut lining, these stressors result in a direct response from stress hormones including cortisol produced by the adrenal glands. Over time with poor, faulty digestion driving up stress, the cortisol pattern can become disregulated creating a myriad of health issues. Chronic stress on the adrenals can then lead to direct inhibition of thyroid function from the Hypo-Pituitary-Adrenal Axis to the Hypo-Pituitary-Thyroid axis as displayed below:

HPA-HPTAxesChart

 

 

 

 

 

 

 

 

 

 

So as you can see, when you stress the gut, you stress the whole body and thyroid function can become compromised as a result.

Protecting the Thyroid

To avoid the domino effect that a problem in the digestive tract can eventually cause in the thyroid, follow these steps:

  1. Heal your gut. Remove or exclude sources that can damage the gut (antibiotic overuse, processed foods/poor diet, food antigens, etc.) and include a combination of gut-healing foods and supplements to build up the integrity of the gut lining.
  2. Mitigate stress. Apply a variety of stress management tools such as yoga, meditation, deep breathing, journaling, or just plain old fun to deal with stress and reduce its impact on your body.
  3. Elimination diet. If you suspect an intolerance to gluten or any other food for that matter, conduct an elimination diet for 30 days, removing the suspected food altogether, charting how your body responds, and then reintroduce it and note any adverse reactions (no matter how small).

For individualized nutrition & digestive health coaching or help balancing your hormones and optimizing thyroid function, visit the Services Page for program options that include Functional Diagnostic Nutrition.

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