Why Gut Health May Be at the Root of Hashimoto’s Thyroiditis

Did you know that women are up to ten times more likely than men to develop Hashimoto’s thyroiditis? This autoimmune condition is the most common cause of hypothyroidism, or an underactive thyroid, in the United States.

Yet many women may not recognize the symptoms—or realize that their thyroid problems can involve more than the thyroid itself.

While genetics, hormones, and immune system differences all play a role, emerging research points to another important connection: your gut health.

Functional medicine is increasingly looking at how the trillions of microorganisms living in your digestive tract interact with your immune system and may influence autoimmune conditions like Hashimoto’s.

Here’s what we know so far, according to one of our functional medicine physicians, Dr. Karrie Hohn.

What Is Hashimoto’s Thyroiditis?

Your thyroid is a small, butterfly-shaped gland in your neck responsible for producing hormones that regulate metabolism, energy, body temperature, and many other essential functions.

“Hashimoto’s thyroiditis occurs when your immune system mistakenly identifies healthy thyroid tissue as a threat and begins attacking it,” says Dr. Hohn. Over time, this autoimmune response can damage the thyroid and reduce its ability to produce hormones.

The condition often develops gradually, with symptoms that can be easy to dismiss or attribute to stress, aging, or hormonal changes. Common symptoms include:

• Persistent fatigue and low energy
• Unexplained weight gain
• Brain fog or difficulty concentrating
• Constipation and sluggish digestion
• Cold sensitivity
• Dry skin and thinning hair
• Changes in menstrual cycles

Because Hashimoto’s is an autoimmune condition, understanding the factors that influence immune function may provide a more complete picture of thyroid health.

Why Are Women More Susceptible to Hashimoto’s?

There isn’t one reason, but several biological differences may contribute:

Immune system differences: Women generally mount stronger immune responses than men. While this can provide an advantage in fighting infections, it may also contribute to a greater susceptibility to autoimmune conditions, in which the immune system mistakenly attacks the body’s own tissues.

Estrogen and hormonal fluctuations: Estrogen influences immune cell activity and inflammation. Hormonal changes throughout a woman’s life, particularly during pregnancy and the postpartum period, may affect the development or progression of autoimmune thyroid disease.

Genetic factors: The X chromosome contains numerous genes involved in immune regulation. Because women typically have two X chromosomes, differences in how these genes are expressed may contribute to increased autoimmune susceptibility.

These factors help explain why women are more vulnerable to autoimmune thyroid conditions, but they’re not the whole story. Research is increasingly looking at the influence of gut health on Hashimoto’s.

The Gut-Thyroid Connection

Your gut contains trillions of bacteria, fungi, and other microorganisms collectively known as the gut microbiome. These microorganisms help maintain the intestinal barrier, produce beneficial compounds, and communicate with immune cells throughout your body.

When the balance of microorganisms becomes disrupted—we call this “gut dysbiosis”—it can influence inflammation and immune regulation.

Autoimmune diseases like Hashimoto’s can also be triggered by intestinal permeability, sometimes called “leaky gut.”

“Leaky gut syndrome occurs when your diet, as well as psychological and physical stress, cause the gut lining to become more permeable to food particles, bacteria, and toxins,” says Dr. Hohn. “When this happens, certain molecules that haven’t been fully digested “leak” through the gut lining and into the bloodstream. The body perceives those molecules as foreign and mounts an immune response to fight those unrecognizable molecules, which leads to inflammation.”

Because Hashimoto’s involves an overactive immune response directed at the thyroid, disturbances in the gut microbiome and intestinal barrier may contribute to the immune dysregulation involved in the disease.

What Does Treatment Look Like, and How Can You Support Gut and Thyroid Health?

At PALM Health, treating Hashimoto’s begins with understanding the individual.

Our medical providers take a comprehensive approach to thyroid evaluation, which may include a thyroid panel assessing TSH, free T3, free T4, reverse T3, and thyroid antibodies, including thyroglobulin and thyroid peroxidase (TPO) antibodies.

Once Hashimoto’s is diagnosed, we look beyond the thyroid to evaluate other factors that may be the underlying cause.

This may involve:

• A comprehensive gut evaluation. Depending on symptoms and medical history, providers may recommend an elimination diet, SIBO breath testing, or advanced stool testing to investigate gastrointestinal symptoms, possible infections, and microbial imbalances.
• Assessing possible food intolerances. Identifying foods associated with digestive symptoms may help guide individualized nutritional recommendations.
• Evaluating environmental exposures. When a patient’s history suggests a relevant exposure, providers may consider targeted testing for substances such as heavy metals or other environmental contaminants and toxins.
• Reviewing lifestyle and nutritional factors. Sleep quality, chronic stress, exercise habits, and nutritional deficiencies can all influence overall health and how a person feels.

As far as treatment, there’s no one-size-fits-all approach. It depends on thyroid function, symptoms, medical history, and other individual considerations.

Everyday Ways to Support Gut and Thyroid Health

“Because Hashimoto’s can often be a consequence of immune system weakness provoked by an imbalanced system, we have to work to re-balance the system,” says Dr. Hohn.

In addition to appropriate medication, potential thyroid hormone replacement, and other medical treatments, this may include:

• Eating a fiber-rich, diverse diet. Include a variety of vegetables, fruits, legumes, and whole grains to nourish beneficial gut bacteria.
• Limiting highly processed foods. Prioritize nutrient-dense, whole foods as the foundation of your diet.
• Prioritizing quality sleep. Consistent, restorative sleep supports normal immune function and overall health.
• Managing chronic stress. Practices such as meditation, breathing exercises, and regular movement may help regulate the body’s stress response.
• Exercising consistently, without overdoing it. Overtraining can be triggering for these kinds of conditions. Aim for a balance of exercise that feels good paired with proper recovery.
• Addressing persistent digestive symptoms and nutritional deficiencies. Work with a medical provider to identify whether additional evaluation or targeted treatment is appropriate.

If you’re experiencing persistent fatigue, brain fog, unexplained weight changes, or digestive issues, it’s worth looking into your thyroid function—especially for women.

At PALM Health, we take a personalized approach that begins with a thorough review of your symptoms, medical history, and appropriate thyroid testing.

But we don’t stop there. Our goal is to understand the bigger picture—not just the thyroid—so we can develop a personalized plan to help you feel and function at your best.