If you were to do a Google search “causes of Crohn’s disease,” you’ll find most articles saying there is no known cause. However, research has been pointing the finger at various microbes for over a decade.  

If you dig a little deeper, you’ll find we are learning that certain microbes are associated with Crohn’s disease. This has shed light on new treatment ideas, which target these microbes. Not only is this promising, it also tells us there are ways we could prevent Crohn’s disease too.

The cause of inflammatory bowel disease, especially Crohn’s disease is currently thought to involve inappropriate, persistent inflammatory response to commensal gut microbes in genetically susceptible individuals. This is important to understand because many microbial imbalances or infections can trigger this inflammatory response… crazy, huh?  

Once the disease has been triggered, an altered immune response results in ongoing gut inflammation and loss of tolerance to intestinal antigens. The loss of tolerance stimulates certain cells, called T-helper cells to produce a nasty slew of proinflammatory cytokines causing collateral damage. It’s a vicious cycle that continues to damage healthy tissue by accident.  However, the genetic part is important because those without the genetic susceptibility are unlikely to develop disease from these commensal microbes or others.

In Crohn’s disease, specific microbes are the trigger in a person with genetic susceptibility. There are many microbes that can set off the inflammation that leads to inflammatory bowel disease – we are only beginning to uncover specific culprits. That being said, let’s take a closer look at three potential microbial triggers – a fungi, a bacteria, and a virus.

1. Candida Tropicalis

A 2016 study that came out in the journal American Society for Microbiology found a significantly higher prevalence of Candida tropicalis in the stool of Crohn’s disease patients. High rates of this fungus were also found alongside anti-Saccharomyces cerevisiae antibodies, which is one way we differentiate Crohn’s disease from ulcerative colitis.

These fungi weren’t on their own though. They were found grouped with two bacterium – E. coli and S. marcescens. This fungus and these two bacterium worked together to make a triple-species biofilm that was thick and larger than normal. These biofilms contributed to dysbiosis in Crohn’s disease.

This study was a fascinating look into the potential interkingdom microbial interactions. Learning more about how fungi, bacteria, and other microbes have evolved to interact with one another within our bodies is only going to expose future insights and novel approaches to treatments.

I chose to highlight the fungus in this study because it was the first of its kind to indicate a fungus as a potential cause of Crohn’s disease. Before this we mostly considered bacteria and viruses. In the quest for solutions to our complicaticated chronic conditions, we must look in every corner.

2. Mycobacterium Avium Subspecies Paratuberculosis (MAP)

Quite the mouthful isn’t it?

Mycobacterium avium subspecies paratuberculosis or MAP for short is a bacteria known for its ability to cause a disease in the stomach of cattle called Johne’s disease. Johne’s disease looks similar to Crohn’s disease, which is how it came to be a major suspect. Actually, some strains of MAP can survive pasteurization, which has raised concerns as to whether or not milk is a more common source of MAP than we realize.

MAP is a clever bacteria that’s capable of hiding in white blood cells, evading immune system alert, and also causing immune system dysregulation. This is the mechanism through which MAP can cause Crohn’s disease – it essentially sneaks around in your body causing an autoimmune response. Interestingly, drugs that are often successful against Crohn’s – rifabutin and clarithromycin – are believed to be successful because they target MAP.

MAP is emerging as a clear cause of Crohn’s disease. Though it’s not widely known yet, research is finding that MAP can cause a variety of gastrointestinal issues. One 2011 report concluded, “If we accept that both ulcerative colitis and Crohn’s disease are caused by specific microorganisms, MAP, a long overdue transformation will take place in the prevention and treatment of these diseases.”

3. Epstein-Barr Virus

Epstein-Barr virus was only discovered 50 years ago. Since its discovery, we’ve come to find that an estimated 90 percent of the adult population has this virus. Epstein-Barr appeared so ubiquitous it was thought to be benign. However, it’s turning out to be closely linked to numerous digestive conditions, such as:

• Crohn’s disease
• Ulcerative colitis
• Peptic ulcer disease
• Acute appendicitis
• Gastric cancers

Epstein-Barr virus is common in numerous conditions where gastrointestinal inflammation is a key characteristic, specifically Crohn’s disease. One study found that while there was no Epstein-Barr virus in normal gastrointestinal mucosa, 55 percent of those with Crohn’s disease had Epstein-Barr virus. Another study found this rate to be 63 percent in Crohn’s patients.

Researchers have found that Epstein-Barr virus can be largely dormant until activated by immunosuppressant drugs, such as steroids. On top of that, immunosuppressant drugs have been found to worsen Crohn’s disease. This is interesting because it goes against what you might think would be a good treatment for Crohn’s disease. Because Crohn’s disease is an autoimmune disease where an overactive immune system attacks the gut lining, you might think immunosuppressant drugs would be a good idea. However, studies are finding that treating Crohn’s with immunosuppressant drugs worsens the condition.

See how that can become a vicious cycle? First, the drugs activate the Epstein-Barr virus, causing Crohn’s. Then, the patient is prescribed more immunosuppressant drugs, which only makes it worse.

The takeaway? If doctors were more apt to test their patients on immunosuppressive drugs for Epstein-Barr virus and activity, they could catch the development of gut conditions early, possibly even prevent them.

My Story

I got my Crohn’s disease diagnosis only six short months after I had just beat breast cancer. I know my Crohn’s disease development was due in part to the chemotherapy I has just been through. Fortunately, in healing my Crohn’s disease I developed personal insight into how autoimmune disease can be significantly influenced and in some cases reversed.

If you’re interested in learning more about this, you can get my guide: What to do if You Have an Autoimmune Disease?

One final note: This isn’t definitive list. There are other microbes associated with Crohn’s disease. Some of these include: Candida species, Saccharomyces cerevisiae, mycobacterium avium sp., yersinia, listeria, helicobacter pylori, e.coli and others.

Resources:

https://www.researchgate.net/publication/308386708_Bacteriome_and_Mycobiome_Interactions_Underscore_Microbial_Dysbiosis_in_Familial_Crohn%27s_Disease

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2718892/

https://www.ncbi.nlm.nih.gov/pubmed/10888733

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3031217/

https://www.ncbi.nlm.nih.gov/pubmed/26282825

https://www.ncbi.nlm.nih.gov/pubmed/22410851

https://www.ncbi.nlm.nih.gov/pubmed/10364028

https://www.ncbi.nlm.nih.gov/pubmed/26307954

https://www.ncbi.nlm.nih.gov/pubmed/25684960