Concussions & Digestive Health


Have you been experiencing changes in your digestion lately? Have you had a concussion in the last year? Did you know they might be connected?

While it may seem like a stretch to assess gut and brain health together, they are actually intricately connected. For this reason it is common to experience digestive changes (ie. change in appetite, increased gas & bloating, change in bowel movement frequency/form, heartburn, pain) following a concussion.

How are the gut & brain connected?

The vagus nerve is one of the main connections between the gut and the brain. The vagus nerve travels from the brainstem (at the base of the skull) all the way down to the colon (and other places). It has numerous functions in the body, but the one we are most interested in is its role in digestion.

The vagus nerve is part of the parasympathetic nervous system (PNS), which along with the sympathetic nervous system (SNS) make up the autonomic nervous system. The function of the PNS is “rest & digest” and the function of the SNS is “fight or flight”, which is activated by stress. It’s important to note that both of these functions cannot be active at the same time.

How is the vagus nerve affected by concussions?

A concussion is a traumatic event. The injury to the brain is interpreted as a stress and as such activates the sympathetic “fight or flight” nervous system. The activation of the SNS shuts down the PNS and vagus nerve activity. This causes digestive functions to slow down; enzyme production and secretion is decreased, gut motility is slowed. There is also a decrease in blood flow to the digestive organs.  

This disruption in function causes increased intestinal permeability, also known as leaky gut. Amazingly, studies are showing the increased permeability can happen within hours following a concussion and stay increased for weeks to months.

How does increased intestinal permeability affect the body?

First, let’s explain what increased intestinal permeability means.

Think of the gut lining as a fence with gates along it. These gates allow certain particles to pass through and enter the bloodstream. The gates are selective for small, digested food particles (and other nutrients). Larger, undigested particles are too big to enter.

After a concussion the gut lining is damaged. The selective gates are still there but now there are also large holes in the fence. The holes allow large particles to enter the bloodstream, that otherwise wouldn’t have been able to. Once they enter the bloodstream the immune system will recognize them as foreign and mount a subsequent attack. The attack causes gut inflammation.

This inflammation, if not fixed, can spread throughout the body to many places, including the brain.

Simply put, concussions can cause digestive symptoms, which in turn can worsen and lengthen concussion symptoms

What can be done to fix it?

The gut needs to be treated, in addition to treating the brain. This includes decreasing gut inflammation, decreasing intestinal permeability and reactivating the vagus nerve. Not only will this help digestion, but it will also improve concussion symptoms (ie. headaches, foggy mind, poor concentration).

To decrease inflammation:

The first step in any post-concussion treatment plan is to start an anti-inflammatory diet. This involves removing processed foods and decreasing sugars, gluten, dairy, alcohol & caffeine. This will help to decrease permeability and inflammation.

To reactivate the vagus nerve:

One of the most accessible methods to do this is gargling. Gargling activates posterior muscles in the throat that then send signals to the vagus nerve to wake up.

For gargling to be effective you need to do it “loud & proud” - ie. make sure your next door neighbour can hear you. To do it start with a cup of water; pour as much in your mouth as you can comfortably gargle and then gargle vigorously for 20-30 seconds. Repeat 2-3 times. If your eyes start to water while you are gargling it means you are doing it right. The vagus nerve is also responsible for stimulating tears.

Note: these treatment options are just a starting point. Depending on presenting symptoms a complete treatment plan may include targeted supplementation, nutrition, acupuncture and/or lifestyle changes.

If you are interested in learning whether this applies to your case please book in for a 15 minute discovery consult with Dr. Emily or if you’re ready to jump in book an initial assessment now.