Do you ever wonder why your thyroid hormone function feels off, yet tests come back normal? Numerous factors affect thyroid health and function including acute and chronic stress, nutrient deficiencies, gluten, infections, toxins, and much more before total breakdown occurs. One of the most profound sources of stress to the thyroid gland stems from your gut microbiome, i.e. the gut-thyroid axis. Keeping your gut microbiome happy and healthy is integral to thyroid health!

Gut-Thyroid Axis

In the past 30-plus years, the study of the gut-thyroid axis has revolutionized the understanding of thyroid health. The gut-thyroid axis refers to the profound interaction of the gut microbiome “talking” to the thyroid gland and vice versa. This arena of research has caused clear patterns to emerge showing changes in your gut health deeply impact your thyroid function.

The gut-thyroid axis is greatly stressed and impaired by the Western diet. The high fat, high sugar, chemical ladened diet stresses microbiome-immune-inflammation management systems causing cellular inflammatory reactions. It impairs the gut structure and microbiome diversity resulting in adverse thyroid hormone and gland function.

Increased Intestinal Permeability

When the gut lining is challenged, it causes immune responses and changes in intestinal permeability. It can cause movement of LPS toxins and other pro-inflammatory immune compounds in the gut into the circulatory and lymph system that eventually affects the thyroid gland as well as other tissues and organs. This negative state of function is commonly known as leaky gut syndrome or increased intestinal permeability. It is considered one of the most common causes for changes in thyroid health.

What Causes Increased Intestinal Permeability

Numerous factors affect the intestinal mucosal barrier and lining. These include processed, packaged, high sugar, high fat, empty calorie foods and beverages, food intolerances, gluten, Round-up/Glyphosate exposures/residues, GMO foods, sedentary lifestyles, laxatives, acid blocking meds, antibiotics, aspirin, ibuprofen and other NSAIDs, blood sugar and statin medications, use of multiple medications/polypharmacy, high stress/cortisol, alcohol, and other environmental toxins. Insufficient nutritional reserves to manage these factors compromise and delay your body’s ability to heal the gut lining. 

Gut Microbiome Structure

The typical Western Diet provides about 10-12 grams or one-third of your daily fiber needs. A lack of dietary fiber starves your gut microbiome and provokes subtle, but powerful changes that lead to inflammatory stress throughout your body.

Dietary fiber acts as a “prebiotic” which feeds the beneficial bacteria, i.e. “probiotics” by a fermentation process. This in turn produces “postbiotics”, i.e. short chain fatty acids (SCFAs) like butyrate.

Postbiotic SCFAs are an energy source and the primary fatty acid necessary for the life and function of intestinal lining cells. SCFAs like butyrate provide a direct impact on neutralizing inflammation and immune regulatory effects in the gut, thyroid, and whole body. They are required to maintain and rebuild the mucosal barrier.

Gut Microbiome Balance and Diversity

The balance of gut bacterial species also affects your thyroid health. A recent meta-analysis study showed decreased levels of Bifidobacteria and Lactobacillus with an overabundance of non-beneficial bacteria (dysbiosis) were commonly found in individuals with changes in thyroid function.

In addition, a dysbiotic gut creates pro-inflammatory stress responses and molecular mimicry that causes a destructive immune attack on the thyroid gland. Dysbiosis is a common underlying issue that interferes with thyroid function and adds fire to immune distress. These issues can go on silently for years before changes are seen with lab values and function.

Impaired Vitamin Production

Western diet, lifestyle, and medications change your gut microbiome, interfering with the natural vitamin production by your gut flora. A healthy gut microbiome naturally synthesizes vitamin K, folic acid/folate, and vitamins B1, B2, B3, B5, B6, B12, and biotin. These nutrients are critical for neuroendocrine (thyroid, adrenal) function, mitochondrial function, antioxidant mechanisms, and cellular metabolism.

Why Do So Many People Need Thyroid Medication?

Diets, lifestyles, and the environmental toxic load have changed from a few generations ago. Simple nutrient deficiencies such as lack of iodine that once led to underproduction of thyroid hormone are now replaced with high levels of free radical stress, insufficient antioxidant stores, and decreased fiber intake. These factors change the health of the trillions of microbes in your gut and how they interface with your entire body.

Breakdown of the structure and function of your gut microbiome leads to cytokine production and toxic stress that erodes away health. It causes high levels of oxidative stress to the thyroid gland that slowly destroys its function over months, years, or decades. It affects the receptor sites for thyroid hormone throughout your body and impairs the functionality of thyroid hormone.

Protection and maintenance of thyroid gland health and hormone function relies on you maintaining a healthy gut microbiome. Evidence shows that the start and progression of thyroid stress and dysfunction is impacted by changes in the composition of your gut microbiome and its integrity.

Levothyroxine/Synthroid thyroid hormone replacement medications and other drugs listed above are in the top 5 drugs prescribed in the US and worldwide. These meds change the gut microbiome and deplete several nutrients. Globally, increasing numbers of individuals are challenged by altered thyroid gland and hormone function. Do you detect a pattern?

Action Plan

To help your gut-thyroid axis, start with your diet. Your food choices directly and deeply impact your gut microbiome diversity, integrity, immune tolerance and resiliency, and the gut-thyroid connection. This impacts all other aspects of your health as thyroid hormone is used by every organ and cell in your body to maintain metabolism.

Strive to make daily, consistent, healthy food choices. Enjoy a diverse range of foods with each season. Try new recipes! Plan. When you are hungry, short on time or energy, it is easy to reach for processed, packaged foods but this adversely changes gut health.

Animal studies showed that a change from a low-fat, high fiber diet to the Western diet of high sugar, high fat, and low fiber altered the gut microbiome in just one day! Human studies show a rapid decline of gut microbiome in five days! How do you feel after a vacation or time of easy fast foods? Or a lifetime of the Western diet?

Teach and engage your kids in planning and making healthy meals. They face increasing health challenges with thyroid, gut, and immune dysfunction. Help the seniors in your life get quality food. They need support too!

If you are in family planning stages, a whole food diet and healthy microbiome is vital. Your baby’s microbiome starts during pregnancy, followed by a large microbiome inoculation with vaginal birth, and then breast feeding.

Fiber feeds your short chain fatty acids to produce butyrate, the most important fatty acid to repair the gut lining and neutralize gut-immune inflammatory responses. Glutamine is the most important amino acid for gut lining repair. Add supplemental support if needed.

Your gut microbiome outnumbers the cells of your entire body. Treat your friendly neighborhood microbiome and yourself well!

Resources:

Leaky Gut Syndrome: More Than Just a Gut Problem

Ten Things that Interfere with Thyroid Function

Gluten Intolerance: What Does It Look Like?

Butyrate Aids Digestive Tract Health: Discover New Tributyrin Plus

Nutritional Tips for Thyroid Health

Mitochondria: Your Battery Pack for Thyroid, Adrenals, and Stress Tolerance

Fiber and Your Gut Mucosal Lining

Revitalize Your Gut: How Prebiotics, Probiotics & Postbiotics Work Together

Glutamine: Critical for Gut, Immune System, and Muscles During Stress and Aging

Thyroid Health Depends on Balanced Methylation

Ashma, Methylation, Leaky Gut Syndrome, and Roundup