How does stress impact the digestive system?
Digestion is controlled by the enteric nervous system, a system composed of hundreds of millions of nerves that communicate with the central nervous system.
Our nervous system has two main modes:
Rest and Digest (parasympathetic nervous system) or,
Fight, Flight or Freeze (sympathetic nervous system)
We need to be comfortably in 'rest and digest' for our digestive system to be functioning at its best. With modern busy lives and emotional pressure, we are far too often locked into the 'fight or flight' stress response. We see clients who have had traumatic and obvious stressful times in their life. However we also often see clients who say they 'don't feel stressed' and so it can be important to understand that being in a driven busy mode (such as looking after kids, studying, exercising, work pressure) is enough for some people to impact the digestive system, without having to feel 'emotionally stressed'. This way of being has a series of physical impacts on the whole body, and for many people it has a damaging impact on gut health.
When your body is feeling under pressure, it goes into fight or flight response and a series of reactions take place. Because your nervous system feels like it needs to get 'ready to run', blood is directed away from all non-essential processes. Certain blood vessels dilate and blood is directed away from your digestive tract, and out towards muscles and heart which slows down digestion. Over time, the body may respond to this with constipation, diarrhoea, or bloating.
digestion and absorption of nutrients
When we are feeling under pressure, the whole immune system is ready to react to danger at any moment. Gastric acid production may decrease when under stress, causing uncomfortable feelings and compromising food breakdown. Long-term stress can cause inflammation in the gut, which can reduce the absorption of some nutrients and become sensitised to certain foods. As the walls of the gut can become more damaged and permeable, undigested proteins can be released into the bloodstream causing inflammation in other areas of the body.
The adult digestive system can be up to 30 feet in length and functions as one long tubular muscle which squeezes and pushes food along as it it broken down into smaller and smaller molecules. This muscle motion is called peristalsis. When the stress response diverts energy away from the digestive system, it can cause slow motility or constipation. Some people may experience the opposite, which an increase in bowel movements and feelings of urgency when under stress. Our unique physical response means that there is no off-the-shelf solution for IBS.
Gut Bacteria and immunity
Did you know that upwards of 70% of our immune system is in the gut? We have an incredible abundance of bacteria in our large intestines that are involved in complex roles in the body, including immunity. Many studies have shown that chemical messengers and hormones released during stressful periods have direct impact on the balance of gut bacteria. Because we need a variety of beneficial bacteria, we understand that stress can play a role in upsetting the delicate microbiome and thereby can impact the strength of our immune system.