The body is composed of a variety of systems that each have individual responsibilities. There are two such systems that are incredibly influential over many bodily functions including disease prevention, energy management, and cognitive function. Although they may seem unrelated, the gastrointestinal (GI) system and thyroid are closely associated with one another and contribute a great deal to overall bodily function.
Few are aware that reduced gut health inhibits thyroid function and increases the occurrence of Hashimoto’s thyroiditis. Conversely, poor thyroid function contributes to intestinal inflammation and leaky gut (intestinal permeability). Better understanding of the relationship between gastrointestinal disorders such as GERD and thyroid dysfunction will lead to improved diagnosis and treatment of both conditions.
The Importance of the Gut
The immune system is a critical player in protecting one’s overall health from external and internal threats. With roughly 70% of one’s immune system located in the gut it is essential that one maintains healthy intestinal function. This portion of the immune system, known as the GALT (gut-associated lymphoid tissues) is composed of several lymphoid tissues containing immune cells that protect the body from harmful substances.
Another important portion of gut function is stomach acid. Appropriate stomach acid levels are needed for a healthy gut. Many believe that reducing acid levels is always the answer to resolving gastrointestinal difficulties. However, poor acid levels can lead to inhibited detoxification, decreased nutrient absorption, and reduced immune function. These factors have a negative impact on thyroid function.
Stomach acid is necessary for a healthy body and is important for the following processes:
- Killing harmful bacteria and parasites
- Breaking down food so it is easily absorbed in the intestine
- Absorbing nutrients and minerals such as vitamin B12 and Iron
- Promoting neurotransmitter and amino acid function
Low acid levels may also cause digestive dysfunction. Reduced digestive rate, known as dysmotility, increases the risk of harmful bacteria growth in the gut. This is frequently caused by reduced acid levels which allows food to remain in the stomach too long thereby allowing bacteria to grow. In addition, if food is not adequately digested when it reaches the intestine it can cause inflammation, leaky gut, and infection. These factors are significant contributors to autoimmune disorders such as Hashimoto’s.
What is GERD (Gastroesophageal reflux disease)?
Gastroesophageal reflux disease, or GERD, is classified as chronic acid reflux and is ranked as the most common GI diagnosis in outpatient care. It may not come as a surprise that the occurrence rate of GERD is increasing worldwide. Studies show that those with chronic conditions most frequently experience negative effects on stomach function. Symptoms of GERD are experienced in a range of severity from mild to tremendous discomfort. In serious cases, one may be diagnosed with Barrett’s esophagus, typified by permanent damage done to the esophagus due to long-term acid reflux.
Symptoms of GERD include:
- Acid regurgitation
- Chronic cough
- Difficulty swallowing
- Chest pain
Causes of GERD are often tied to lifestyle habits and contributing health conditions. Common contributors of GI difficulties include:
- Diet including chocolate, citrus, alcohol, saturated fats, tomatoes, garlic, onion, caffeine
- Large meals
- Restrictive clothing
- Various medications
One of the greatest contributors of GERD is thyroid disease. Conversely, those with GERD are at greater risk of developing thyroid disease.
The Gut’s Influence of the Thyroid
A properly functioning thyroid requires an equally functional gut. The thyroid relies on good bacteria in the gut to convert inactive thyroid hormone (T4) into the active form (T3). This process requires intestinal sulfates that are produced by healthy gut bacteria. Intestinal dysbioisis (improperly balanced pathogenic and helpful bacteria), which can be caused by GI issues such as GERD, reduces the conversion rate of T4 into T3. Nearly 20% of the body’s T4 is converted into T3 by the GI tract. Without the substantial influence of the gut, the body is at serious risk of incurring a T3 deficit and thereby hypothyroidism.
The Thyroid’s Impact on the Gut
Thyroid hormones influence nearly every system in the body and the gut is no exception. Perhaps the most important thyroid hormones, T4 and T3, help protect gut mucosal lining from stress induced ulcers. Various studies have found that reduced levels of T3, T4, and abnormal Reverse T3 levels relate to ulcer formation in the stomach and small intestine.
The thyroid also influences immune system function through hormone production and regulation. Both thyrotropin releasing hormone (TRH) and thyroid stimulating hormone (TSH) are involved in developing and protecting the GALT. Thyroxine (T4) also helps protect the gut by preventing over-expression of intestinal intraepithelial lymphocytes (IEL). Overabundance of these T cells can cause inflammation in the gut, which promotes thyroid and GI dysfunction.
Protecting Yourself from GERD and Thyroid Disease
Regardless if one is being treated for a thyroid condition or GERD, it is important that both conditions are adequately analyzed and considered. Because the two conditions are so closely related, it is difficult to resolve one without also treating the other.
Perhaps the best method of optimizing thyroid function is through bioidentical hormone replacement therapy. This approach utilizes natural T3 and T4 hormones that the body recognizes and can easily use. Some treatments may also prescribe time-released T3 to more precisely support individual thyroid function.
Resolving thyroid dysfunction caused by GI issues requires optimizing one’s diet and may demand nutrient supplementation and lifestyle changes. Systematically removing inflammatory foods from one’s diet is greatly beneficial in healing one’s gut. Common problem foods include: dairy, yeast, gluten, soy, and eggs. Everyone has their own unique sensitivities and intolerances so it is important that each person identifies them for themselves.
Protecting one’s health requires taking care of the various interrelated systems in the body. Ensuring that one’s lifestyle supports their thyroid and gut can lead to a resolution of GERD and thyroid disease. Appropriate treatments and lifestyle changes may not only restore thyroid and gastrointestinal function, but they can improve metabolism, weight, energy, and mood as well. Improve your health by optimizing your gut and thyroid through knowledgeable and healthy choices.