When you are in a constant state of stress, the vagus nerve and the sympathetic ‘fight or flight’ nervous system will be switched on, which means that the nervous system cannot be in “rest-and-digest” mode at the same time.
Stress and the Gut: What's the Link?
Have you ever experienced butterflies in your stomach? A gut reaction? Your stomach doing somersaults? Then you've experienced the gut-brain axis in action. Here's what you need to know.
The gut-brain connection is a relatively new field of research, and it's a truly fascinating one. It studies the interaction between the gut and the gut microbiota, with the nervous system.
The gut and the nervous system are in constant communication via several mechanisms.
The primary one being the vagus nerve.
INTRODUCING THE VAGUS NERVE
The vagus nerve is a long nerve that begins at the brain stem and connects to most of your vital organs, including the gut.
The vagus nerve is responsible for communicating messages to and from the gut, and it does this through fibres that are connected to cells in the gut lining. These cells collect information from the gut and the microbiome and send the information up to the brain.
An example of a message could be informing the brain that you are hungry or full.
About 90% of the messages are sent from the gut to the brain and only 10% from the brain to the gut.
This information superhighway (as it’s often called) is the main driving force of the parasympathetic nervous system, which regulates our “rest-and-digest” response when we are in a state of calm, and is the counterpart to the sympathetic nervous system which controls your “fight-or-flight” response in stressful situations.
THE VAGUS NERVE AND STRESS
When you are in a constant state of stress, the vagus nerve and the sympathetic ‘fight or flight’ nervous system will be switched on, which means that the nervous system cannot be in “rest-and-digest” mode at the same time. This can create shifts in regulating the speed at which food travels through the digestive tract and the release of gastric secretions.
This is one reason why people who often experience chronic stress may also experience digestive issues such as bloating, gas, problems with stool frequency and abdominal pain.
Another negative impact of stress on the gut is that it can reduce the amount of anti-inflammatory molecules such as short-chain fatty acids produced by the gut microbiota.
These molecules help to lower inflammation more generally in the body.
Chronic and high production of stress hormones, such as cortisol, can also have a significant impact on the strength and integrity of the gut epithelium.
If the epithelium becomes weakened and “leaky” (sometimes referred to as ‘leaky gut’) it can allow toxins and potential pathogens into the bloodstream, triggering an inflammatory immune response.
When our body is in a constant state of inflammation as a result of immune responses, it can lead to other immune related conditions.
HOW TO PROTECT THE VAGUS NERVE
We know that the best way to stimulate the vagus nerve is to relax. To practice
slow breathing exercises, yoga, meditation, walks in nature - activities that stimulate calm and keep cortisol at an appropriate level.
Eat a Mediterranean diet
The Mediterranean approach to eating focuses on enjoying a wide array of local, seasonal foods, rich in vegetables, fruits, fish, meat, nuts, olive oil, herbs and spices. As well as a little red wine!
This provides rich sources of fibre and polyphenols that can positively support and nourish the gut microbiota.
Make gut health a priority
Do this via a diet that supports a diverse gut ecology with myriad and many sources of dietary fibre.
This can be found in all vegetables, fruit, wholegrains and nuts & seeds.
Include fermented foods or a probiotic supplement alongside.
A healthy and happy gut microbiota helps to support a healthy and happy gut-brain connection.
Moderate aerobic exercise may reduce levels of stress hormones, such as adrenaline and cortisol and stimulate the production of endorphins. Counterbalance high intensity exercise with restorative movement such as gentle yoga or pilates.