Exploring Trauma, Digestion and the Vagus Nerve: Part I
When people experience trauma, the brain communicates a message of danger to our gut via the vagus nerve. Your vagus nerve, sometimes called the wandering nerve, turns on the fight-or-flight response, engaging the sympathetic nervous system. Once in sympathetic, the body sends signals to your digestive muscles to constrict or relax, to stimulate or reduce stomach acid and gut motility and can even alters hunger cues. It’s similar to losing your appetite before a big event. (1) The sympathetic nervous system response reroutes resources away from digestion so you have the energy and strength to run really fast, fight really hard, or scream really loud. But with trauma, the messages from our brain to our gut tend to continue repeatedly - and that long term disruption can have lasting effects on our gut microbiome.
“Of all psychiatric syndromes, PTSD has one of the strongest brain-body relationships, with repeated cycles of trauma adding to the wear and tear on delicate tissue” (2). Physical digestive symptoms associated with PTSD include IBS - diarrhea, constipation, bloating, as well as stomach ulcers, gall bladder disorders and more.
When your microbiome is unbalanced from trauma it communicates that message of chaos back to our mind via the vagus nerve. It can become a harmful cycle of the embodied sensation of danger, repeating messages between the brain and gut that the body needs to fight or flee even though safety is abundant.
To make things worse, the digestive disorders associated with trauma affect how well your body is able to absorb nutrients from food. Nutrients in our food fortify our bodies and can serve as a buffer against stress. If we are not absorbing B vitamins, magnesium and other essential minerals, we are decreasing our body’s ability to handle everyday stressors.
So to end this harmful cycle, addressing both the embodied brain and the gut is vital. In fact, starting with the microbiome can be very effective. “When you feed a traumatized mouse one of two specific types of normal gut bacteria, lactobacillus rhamnosus or bifidobacterium longum, the mouse becomes calmer” (3).
People experiencing PTSD have reduced levels of “good” bacteria - some of these strains are known to protect us from inflammatory symptoms like allergies, skin disorders and asthma - they also help to bolster the epithelial tissue, or the gut lining to protect us from leaky gut. (4)
So, if we want a balanced mind, we need a balanced microbiome. Your gut microbiome can act as a guard to ward off the long-lasting effects of trauma. There are many factors to consider beyond probiotics for repopulating a flourishing microbiome - like our food choices, nutrient absorption, vagal tone, and sleep, but bolstering the microbiome can be a good place to start.
