The Missing Link in Gut Healing: Your Vagus Nerve

Welcome to Healthy Gut Healthy Thyroid!

This is your weekly roundup of the BEST actionable steps for those people with thyroid and autoimmune thyroid conditions who want to restore their health…by healing their gut. Whether you have hyperthyroidism or Hashimoto’s you will benefit from the content in this newsletter.

In today's issue:

• Main Topic: The Missing Link in Gut Healing: Your Vagus Nerve

• Podcast Review: 5 Ways To Lower Thyroid Antibodies

• Ask Dr. Eric: Is a vagus nerve stimulating device safe to use?

The Missing Link in Gut Healing: Your Vagus Nerve

Although I’ve spoken about the vagus nerve in previous newsletters, I wanted to write an article that goes deeper into the importance of the longest cranial nerve in the body. The vagus nerve begins in the brainstem and travels through the neck, chest, and abdomen.

It innervates the heart, lungs, and gut as part of the parasympathetic (“rest and digest”) nervous system. When you think about it, it’s pretty amazing—we breathe, pump blood, and digest food without consciously thinking about it, and we have the vagus nerve to thank for much of this.

On the other hand, if you’re constantly in “fight or flight” mode, this can negatively affect respiration, cardiovascular function, and digestion. This is one of the main reasons why I’m always emphasizing the importance of stress management and getting your body into a rest-and-digest state.

Fight-or-Flight vs. Rest-and-Digest

Both the sympathetic nervous system and parasympathetic nervous system are part of the autonomic nervous system. While you ideally want to spend most of your time in a “rest and digest” state, the sympathetic nervous system is also important—it helps you respond to acute stress and perceived danger.

The problem is that chronic stress inhibits the parasympathetic nervous system, and many people today are stuck in a chronic stress response. And while there often isn’t much you can do to completely eliminate—or even significantly reduce—your stressors, you can do things to help shift your body toward a more parasympathetic state.

The Role of the Vagus Nerve in Gut Health

Since this is the Healthy Gut Healthy Thyroid newsletter, I want to focus on how the vagus nerve specifically influences gut health. Here are a few key ways it does this:

Regulation of stomach acid, digestive enzymes, and bile flow. The vagus nerve plays an important role in stimulating stomach acid secretion, which is why chronic stress can lead to low stomach acid. In addition, it helps trigger pancreatic enzyme secretion and signals the gallbladder to release bile—both of which are essential for proper digestion and nutrient absorption.

Influence on gut motility and bowel regularity. The vagus nerve controls peristalsis, the wave-like muscle contractions that move food through the digestive tract. If you’re constantly in fight-or-flight mode due to chronic stress, motility can slow down, increasing the likelihood of constipation and sluggish digestion.

Impact on the gut microbiome and microbial diversity. Research also suggests that vagal tone influences the gut microbiome by regulating motility, secretion, and immune signaling within the gut. A well-functioning vagus nerve helps create an environment that supports microbial diversity, while chronic stress and impaired vagal signaling can contribute to dysbiosis (imbalances in the gut flora).

Connection to increased gut permeability (leaky gut) and immune signaling. While the vagus nerve doesn’t directly innervate the intestinal epithelium, research shows that it can still modulate intestinal barrier permeability through immune and inflammatory pathways.¹ As a result, vagus nerve dysfunction may be a contributing factor in increased intestinal permeability, commonly referred to as a leaky gut.

Signs Your Vagus Nerve May Need Support

You can’t always rely on symptoms alone to determine whether someone has vagus nerve dysfunction, but if you’re dealing with chronic stress and digestive symptoms, you can probably benefit from vagus nerve support—especially if your digestive symptoms worsen during stressful periods.

Some common signs that vagal tone may be low include bloating, reflux, constipation, diarrhea, food sensitivities, difficulty tolerating supplements, shallow breathing, poor stress resilience, and feeling “wired but tired.” While these symptoms aren’t exclusive to vagus nerve dysfunction, they often point to an underlying imbalance in the autonomic nervous system.

How to Improve Vagus Nerve Health Naturally

So what can you do to support the health of your vagus nerve? Here are a few effective options.

A. Mind-Body Medicine. Incorporating mind-body medicine techniques can help support vagus nerve function. This may include diaphragmatic breathing, breathwork, meditation, yoga, or other relaxation techniques.

The key is consistency. Ideally, you want to establish a daily routine rather than using these tools only when stress levels are high. You don’t need to spend 30–60 minutes per day—starting with just five minutes and gradually increasing the duration can be very effective.

B. Vagus Nerve Stimulation Exercises. In addition to mind-body medicine, you may want to include exercises that directly stimulate the vagus nerve. Humming, singing, and vigorous gargling are simple options. Cold exposure, such as cold showers or cold plunges, can also stimulate vagal activity.

This list isn’t all-inclusive. Other techniques include mindful swallowing, gentle neck stretches, self-massage along the sides of the neck, and certain eye movement exercises. The visual system connects the brainstem and vagus nerve pathways, which is why specific eye movements can help activate the vagus nerve.

C. Nervous System Retraining. Some people need to go beyond mind-body practices and vagus nerve exercises and incorporate nervous system retraining. Chronic illness and trauma can cause the limbic system to become stuck in a heightened threat response, and nervous system retraining can help rewire these patterns.

Dr. Cathleen King, the founder of Primal Trust, discusses using “pattern interrupts” to help retrain the brain and nervous system. She also cautions against starting with nervous system retraining too early, as it can be counterproductive for some people. Instead, she recommends beginning with vagal toning to increase autonomic nervous system capacity before moving on to more advanced retraining techniques.

How Nervous System Retraining Affects the Limbic System

The limbic system is a group of brain structures involved in emotion, behavior, and stress responses. Its primary components include the hypothalamus, amygdala, thalamus, and hippocampus.

The amygdala is responsible for processing emotional responses and threat perception, and it often becomes overactive when the nervous system is dysregulated. In contrast, the hippocampus—important for memory consolidation and learning—tends to become underactive.²

Nervous system retraining can help calm an overactive amygdala while supporting hippocampal function. Over time, this can reduce exaggerated stress responses, improve emotional regulation, and make it easier for the body to shift out of fight-or-flight and into a healing state.

How Can Supporting the Vagus Nerve Help With Complex Conditions?

People dealing with tick-borne infections such as Lyme disease or bartonella, mold toxicity, or long-haul COVID often wonder how vagus nerve support fits into their healing plan. The reason is that these conditions can significantly dysregulate the nervous system, keeping the body stuck in fight-or-flight mode.

Stimulating the vagus nerve can help reduce inflammation, support immune function, and improve digestion. By activating the parasympathetic nervous system, you’re creating a more favorable internal environment for healing.

This doesn’t mean that vagus nerve support alone will resolve complex conditions like chronic Lyme or mold toxicity. However, it can be a very important piece of the puzzle. This isn’t just my clinical experience—I’ve also had practitioners on my podcast discuss how vagus nerve stimulation and nervous system retraining can play a major role in recovery from complex, chronic illnesses.

Final Thoughts

If you’ve been doing “all the right things” for gut healing but still feel stuck, it may be time to look beyond food and supplements and consider your nervous system. Supporting the vagus nerve helps shift your body into a state where healing is actually possible.

While vagus nerve support isn’t a standalone solution, it often serves as the missing link that allows other gut-healing strategies to work more effectively.

Which Hyperthyroid Healing Diet Should You Follow?

There’s no single diet that everyone with hyperthyroidism should follow. Diet selection is a highly personal choice that must consider individual health conditions, lifestyle, and preferences.

In my book, The Hyperthyroid Healing Diet, I explore three different diets in detail, explaining what each involves and how you can start implementing the right one for you. This book will benefit those with Graves' disease, toxic multinodular goiter, and subclinical hyperthyroidism.

There is a lot of confusion when it comes to the foods people with hyperthyroidism should eat and which ones they should avoid, and the truth is that there isn’t a single diet that fits everyone perfectly. That’s why The Hyperthyroid Healing Diet doesn’t just focus on one diet, but instead gives multiple diet options, while at the same time guiding you towards the one most suitable for your situation and condition.

Note: those who purchase The Hyperthyroid Healing Diet will also gain access to the online resources, which includes dozens of recipes, checklists related to the different diet options, and a few bonus chapters not included in the book.

By reading this book you will discover the following:

✅ The ideal diet for Graves’ disease, toxic multinodular goiter, subacute thyroiditis, and subclinical hyperthyroidism

✅ Hidden sources of common allergens and other ingredients to avoid 3 ways to detect specific food triggers

✅ How much protein those with hyperthyroidism should consume on a daily basis

✅ The truth about food sources of iodine

✅ How to increase muscle mass and bone density

✅ What diet you should follow if you’re a vegan or vegetarian

✅ Addressing weight loss and weight gain concerns

✅ What you need to do to achieve optimal adrenal health How to optimize your adrenals, improve sleep quality and duration, and heal your gut

✅ And much, much more!

Click Here to Order the Hyperthyroid Healing Diet

Save My Thyroid Podcast Review

I have a podcast called "Save My Thyroid", where I discuss how people with hyperthyroidism and Hashimoto's can save their thyroid and regain their health. And during each edition of this newsletter I'll briefly discuss a recent podcast episode.

In a recent podcast episode I discussed 5 Ways to Lower Thyroid Antibodies. In this conversation, I walk through what thyroid antibodies actually mean and why they can fluctuate from one test to the next. I then break down five approaches that can greatly help lower thyroid antibodies. The goal is to help you see where your efforts matter most and why a layered approach usually works better than relying on a single strategy.

If you’ve been trying to make sense of your antibodies or you’re unsure what to do next, this episode can offer some much-needed clarity.

Ask Dr. Eric

During every issue I'll answer a question or two that I think can benefit most people with a thyroid or autoimmune thyroid condition. If you'd like for me to consider your question for a future edition of this newsletter email your question to [email protected].

QUESTION: IS A VAGUS NERVE STIMULATING DEVICE SAFE TO USE?

Dr. Eric, I’ve heard you mention vagus nerve exercises, and wanted to know your thoughts on vagus nerve stimulators, and whether they are save for those with thyroid conditions?

Thank you for your question! While I can’t say that this is a common question, since the focus of this article is on the vagus nerve I figured this would be a good “Ask Dr. Eric” question for this newsletter edition.

As I discussed in the main section, ideally you want your body to be in a “rest and digest” state most of the time. Unfortunately, many people are stuck in “fight or flight” mode. Supporting the vagus nerve can help shift the body in the right direction, and I covered a number of different ways to do this.

However, I intentionally didn’t mention vagus nerve–stimulating devices earlier, as I wanted to focus on them here. At-home vagus nerve stimulators, such as Truvaga and Pulsetto, do in fact stimulate the vagus nerve.

How Do At-Home Vagus Nerve Stimulators Work?

These devices are relatively simple to use. They are placed around the neck, and you use an accompanying app to select a session and adjust the intensity. If you’ve ever used a TENS unit, the sensation is similar. As you increase the intensity, you’ll feel gentle electrical impulses, and most manufacturers recommend running one or two sessions per day.

As for whether you need to use a vagus nerve-stimulating device, in most cases my answer would be “no,” since the other techniques I mentioned earlier can be just as effective. That said, some people choose to use an at-home vagus nerve-stimulating device for additional support.

It’s important to remember that everyone is different. While some people notice significant benefits from using a vagus nerve-stimulating device, others may experience greater results by incorporating mind-body medicine techniques or practicing simple vagus nerve exercises such as humming, gargling, and/or cold exposure.

Are At-Home Vagus Nerve Stimulators Safe to Use?

When it comes to thyroid and autoimmune thyroid conditions, there isn’t much research specifically looking at whether at-home vagus nerve–stimulating devices are safe or unsafe. I also can’t say that many of my patients have used these devices.

One important consideration is that these at-home devices are placed in close proximity to the thyroid gland. This doesn’t necessarily mean they’re harmful to thyroid health, but it would be reassuring to see studies evaluating their effects in people with hypothyroidism and hyperthyroidism.

On the other hand, there are numerous studies showing that vagus nerve stimulation can benefit people with various autoimmune conditions. This isn’t surprising, as I mentioned earlier how supporting the vagus nerve can positively influence immune health.

So, for someone with Graves’ disease or Hashimoto’s (or antibodies for both conditions), vagus nerve–stimulating devices might help address the autoimmune component. Since autoimmunity is responsible for approximately 90% of hyperthyroid and hypothyroid cases, one could argue that improving immune regulation through vagus nerve support may indirectly help with thyroid hormone balance.

That said, as I mentioned earlier, because these devices are positioned near the thyroid gland, I can’t say there is absolutely no risk if someone has an existing thyroid condition.

Additional Thyroid-Related Resources

Click Here for 5 Ways to Lower Thyroid Antibodies (episode 226)

Click Here to access hundreds of thyroid-related articles and blog posts

Click Here to join the Graves’ disease and Hashimoto’s community

Click Here to purchase one of Dr. Eric’s thyroid-related books

Click Here to work with Dr. Eric and his team

📚References:

(1) https://pmc.ncbi.nlm.nih.gov/articles/PMC9787579/ 

(2) https://pubmed.ncbi.nlm.nih.gov/25217299/

That’s a wrap