Is there a Connection between EBV and SIBO?

EBV and SIBO? I have been asked too many times if there is any connection between Epstein-Barr Virus (EBV) and Small Intestinal Bacterial Overgrowth (SIBO). There is still not a single study that I am aware of. However, I want to share with you a very intriguing hypothesis that is both logical and plausible.

The Vagus Nerve 101

The vagus nerve is the largest nerve in your body, the “wandering nerve.” It starts at the base of your brain and literally wanders through the majority of your body. That includes your lower neck, upper thorax, muscles of larynx and esophagus, heart, and lungs. Most importantly, in innervates your entire intestinal tract, from the stomach to the anus.

SIBO 101

SIBO is an overgrowth of bacteria (often translocated from the colon, and not pathogenic by nature) in the small intestine. It is optimal for our beneficial colonic bacteria to eat fibers from our food in the colon. But it is not so good if the same colonic bacteria migrate upstream into the small intestine, take over, gorge in the fiber there and start fermenting it there.

Normally, the small intestine has much lower numbers of beneficial bacteria than the colon. Unlike the colon, small intestine is the site of absorption of most of the nutrients from your meal. The rest of your meal (which should be rich in indigestible fiber) travels all the way to the colon to feed the beneficial bacteria there. They simply LOVE that fiber. They consume it, they “poop”, and that “poop” is the precious short chain fatty acids (SCFAs). The colonic cells require SCFAs for proper function! Not only that, but SCFAs have been found to migrate into the blood stream and feed our “Tregs”. T-regulatory cells are that some of the most vital immune regulatory cells that protect us from inflammation and autoimmune processes.

Unfortunately, when the colonic bacteria move to the small intestine where they do not belong, they still love to consume the same foods (fiber). And while fermentation is perfect in the colon, it is not in the small intestine. We end up with bloating, gas, distention, malabsorption and inflammation, for starters.

This is grossly oversimplified here,  and there are various other reasons one can develop SIBO. However, for the purpose of our conversation, let’s focus on the fact that SIBO is a symptom of gastrointestinal tract not moving our foods properly.

The Vagus Nerve and SIBO

And what innervates the intestinal tract? What causes the foods we swallow to actually move all the way inside our gut? There are two things. The vagus nerve innervates the whole intestinal tract. If you cut out vagus nerve, foods would just not move! A failing vagus nerve in the small intestine can cause small intestinal “dysmotility” (Dukowicz et al., 2007).  As the vagus nerve weakens, so does migrating motor complex (MMC), wave-like contractions that move foods along in the intestines (Miyano et al., 2013). When these waves do not sweep foods forward in a timely fashion, we are setting the stage for SIBO.

Why Do some of my  Clients Have both EBV and SIBO?

We have learned a lot about the effect of vagus nerve on gut motility and SIBO in the last few years. But what we may not appreciate enough is that vagus nerve can also be affected by EBV!!!

Before I knew anything about EBV, I was busy supporting clients with SIBO, starting with Dr. Gerard Mullin’s patients at Johns Hopkins Integrative Medicine and Digestive Center years back. It was only a few years into working with SIBO that I started to focus on Epstein-Barr Virus at the same time. Stil,l I never really looked at SIBO and EBV as related conditions until more recently.

The issue of the impaired vagus nerve might explain why I am seeing just a few too many cases of clients that actually have both SIBO and chronic EBV to feel it is pure coincidence. EBV can travel to various parts of the human body. Just a few weeks after the initial infection, it leaves the blood stream and moves into spleen, liver, thyroid, muscles, and even brain, to name a few. And yes, it can also get “on your nerves”, quite literally! It CAN get into your vagus nerve!!!

Could it be that a viral infection like EBV (and not just a bacterial infection) can be one of the reasons why the vagus nerve is affected, and thus be another cause of SIBO?

The Vagus Nerve and Chronic Fatigue/Fibromyalgia?

Not only can vagus nerve dysfunction cause SIBO, but the vagus nerve damage from EBV may be another factor behind chronic fatigue syndrome and even fibromyalgia!

In his Vagus Nerve Infection Hypothesis (VNIH) for chronic fatigue syndrome Michael VanElzakker, a Tufts neuroscientist,  makes the connection between EBV, chronic fatigue, fibromyalgia and the vagus nerve (VanElzakker, 2013). He suggests that as the vagus nerve “wanders” through the preferred EBV’s locations like esophagus, spleen, lungs, or stomach, it will eventually come in contact with the localized EBV infection (and other herpes viruses for that matter).

Glial Cells are Supposed to Protect the Vagus Nerve!!! What Happened?

VanElzakker claims that reactivated EBV moves outside the nerves. Our immune cells of the nervous system called glial cells (or astrocytes) see the virus and try to digest it. Glial cells are very problematic. In the Amazon best-selling book Epstein-Barr Virus Solution, I discuss glial cells in more detail in the context of EBV breaking down the brain blood barrier (BBB), where it infects the brain and causes the glial cells to activate in the brain as well.

Here, in the vagus nerve, glial cells have the job of protecting it. The problem with those glial cells is that, when activated, they produce highly inflammatory and neurotoxic compounds. Examples are interleukins 1B and 6, Tumor Necrotic Factor-a, glutamate, prostaglandins, nitric oxide, and free radicals. This in turn will fuel more viral infection. According to VanElzakker, the vagus nerve receptors tell the brain about the infection. This causes the shutdown of the body by sending signals like fatigue, flu-like symptoms, pain, etc. The body is told to slow down and stop processing, eating, and thinking.

Is EBV a Set-Up for Fibromyalgia?

According to this hypothesis, EBV can cause localized immune system activation around the vagus nerve. Since it is localized, it will not show positive in blood work and will be missed in medical practice.

As the glial cells release their chemicals in the dorsal horn of the spinal cord, this can also cause an increase in pain sensitivity. As this excitation of glial cells continues, eventually this pain spirals instead of shutting down. The pain response can become “pathological,” VanElzakker says. Even the slightest touch will cause pain. Why would it be different from shingles, another herpesvirus, which causes chronic pain when infecting the trigeminal nerve? Animal studies do show that infection of the vagus nerve causes fatigue and flu-like symptoms.  It does not do that when the vagus nerve is cut off [I do hate it when they do experiments on animals…].

VanElzakker may just be right that viruses like EBV can affect the vagus nerve, causing chronic fatigue and/or fibromyalgia/ allodynia. On the other end of the spectrum, pathogenic infections like EBV may impair the vagal nerve function, shutting down MMCs and contributing to dysmotility, eventually leading to SIBO.

When to Test for SIBO and EBV

We need more research to prove VanElzakar’s hypothesis.

In the meantime, if you have a bad case of gastrointestinal symptoms along with your EBV (e.g. constipation, diarrhea, either or, bloating, gas, distention, abdominal pain, etc.), consider a lactulose breath test for SIBO.

If you already have SIBO and you are not getting better despite your medical or herbal treatment, and you remember once having a really bad flu that would not go away (or mono), consider testing for EBV. Click here to learn what and where to test independently if you do not have a doctor, and how to interpret your results.

If you have chronic fatigue or fibromyalgia, it warrants testing for EBV as well. Learn more about chronic fatigue and EBV in my other blog.

In the meantime, VanElzakker’s hypothesis may explain why antioxidant and anti-inflammatory support is so effective in lifting my clients from their chronic fatigue, which is such a pervasive complaint in people affected with chronic EVB infections.

More on all topics EBV, including effective nutritional therapies,  is available in The Epstein-Barr Virus Solution book.

A sample chapter is available here.



Dukowicz, A. C., Lacy, B. E., & Levine, G. M. (2007). Small intestinal bacterial overgrowth: a comprehensive review. Gastroenterol Hepatol (N Y), 3(2), 112-122. 

Miyano, Y., Sakata, I., Kuroda, K., Aizawa, S., Tanaka, T., Jogahara, T., . . . Sakai, T. (2013). The role of the vagus nerve in the migrating motor complex and ghrelin- and motilin-induced gastric contraction in suncus. PLoS One, 8(5), e64777. doi:10.1371/journal.pone.0064777

VanElzakker, M. B. (2013). Chronic fatigue syndrome from vagus nerve infection: a psychoneuroimmunological hypothesis. Med Hypotheses, 81(3), 414-423. doi:10.1016/j.mehy.2013.05.034