In my previous post, I talked about the impact stress has on our gut health. I said I’d get into some nerdy science with that. So let’s expand on that topic and get into some nerd talk.
Have you ever heard that two heads are better than one? Fortunately, we have two brains in our body - the brain in our head and a second brain in our gut. And they’re connected both physically and chemically. It’s literally true that a healthy mind helps create a healthy body and a healthy body helps create a healthy mind.
Our gut and brain are connected physically through the vagus nerve, the longest nerve in our autonomic nervous system. The word vagus is latin for “wandering”. It got this nickname for the way it wanders all the way from the brainstem and passes through the throat, esophagus, lungs, heart, diaphragm and intestines. It carries crucial information from the organs to the brain and back and helps carry out important functions, such as regulating digestion, modulating the immune response and sending anti-inflammatory signals.
This is also the main nerve of our parasympathetic nervous system and is critical for telling our body to turn off the “fight or flight” response tied to stress and turn on the “rest and digest” response to calm the body down. So think of the vagus nerve as the superhighway of communication throughout your body.
Our gut and brain are connected chemically through neurotransmitters. These are chemical messengers that your body can’t function without. Their job is to carry signals (“messages”) from one neuron (nerve cell) to the next target cell. These signals are sent via the vagus nerve. There are over 40 neurotransmitters in the nervous system, but there are a handful that are important in regulating our digestion and mood. That’s right - there’s a direct connection between our gut health and our mental health.
Acetylcholine - This is produced in the brain and signals the nerves in the gut to start digesting by activating the parasympathetic nervous system. When this signal is sent, via the vagus nerve, the intestines start moving and digesting and the immune system is reactivated, which is suppressed during stress.
GABA - This is also produced in the brain and signals the nerves in the gut to suppress the sympathetic nervous system. When GABA is low, it’s difficult for the body to relax after stress, and can lead to anxiety, depression, insomnia and mood disorders.
Serotonin - This is known as the “happy” chemical. It enhances our feelings of well-being, regulates mood, gut motility, sleep patterns, sexuality, anxiety, appetite and pain. 90% is produced in the gut (the other 10% in the brain). If the gut is unhealthy due to a poor diet or chronic stress, production of serotonin is compromised, which can lead to feelings of depression, anxiety, decision fatigue and mood disturbances
Dopamine - This is known as the “pleasure” chemical, as it’s responsible for allowing you to feel pleasure, satisfaction and motivation. 50% of it is produced in the gut, 50% in the brain. This helps regulate our learning, attention, memory, and mood. Similar to serotonin, if the gut is unhealthy, production of dopamine can be compromised and you could have a harder time learning new things and maintaining concentration.
Norepinephrine - This is produced entirely in the adrenal glands in the gut. Higher levels of norepinephrine in the body enhance the overall rate of fat loss by stimulating the release of fatty acids from fat cells into the bloodstream for burning as fuel and providing more energy to the body. It also plays a role in the sleep-wake cycle, increases attention and focus and helps with memory storage.
So how do neurotransmitters and the vagus nerve work in harmony?
The activity of a person’s vagus nerve, which can be determined by a person’s heart rate and heart rate variability, is known as vagal tone. A lower heart rate and higher HRV indicate increased vagal activity. Increased vagal activity means neurotransmitters are sent throughout the body appropriately helping to regulate stress and properly transition back and forth from “fight or flight” to “rest and digest”, reduce the risk of chronic stress and maintain a positive mindset.
You may recall from my previous article that eating in “fight or flight” mode can negatively affect digestion, regardless of how many vegetables are on your plate. A low vagal tone can be associated with depression, anxiety and other mood disturbances since the chemicals needed for a sense of happiness, pleasure and wellbeing are not getting produced and sent to the brain.
How does the vagus nerve get irritated? A few ways stand out:
Excess consumption of spicy foods and particularly alcohol.
Release of stress hormones that override the parasympathetic nervous system.
A high-fat diet. Now this is not the healthy kind of fat that you get in avocados and fish. These are foods high in trans and saturated fat that come from processed foods, dairy and red meat.
Signs of high vagal tone:
Resilience to stress
Good heart rate and heart rate variability
General sense of well-being
Healthy appetite (tells the brain when the stomach is full)
Healthy bowel movements
Signs of low vagal tone:
Inflammation (stomach cramps, diarrhea, constipation, gas)
Loneliness
Depression
Anxiety
Elevated heart rate and blood pressure
Heart attack
Stroke
This is yet another reason why a healthy and balanced diet and lifestyle is so important. You want to make sure the communication between your gut and your brain is healthy and active and it’s sending all the right signals for proper functions throughout your body.
Now, let’s go through some ways that you can naturally stimulate the vagus nerve and increase vagal tone:
1. Cold Plunge - Immerse yourself in hot water for 5 minutes and then immediately plunge into cold water for anywhere from 20 seconds to two minutes. This builds resilience to stress, which in turn helps build the immune system. The shock of going from hot to cold supports the body’s ability to transition between sympathetic and parasympathetic nervous systems. Yes, this can be a brutal two minutes, but I promise you will feel in-freaking-credible when you get out. If you don’t have access to hot and cold tubs, this can be done at home by going from a hot bath to a cold shower or turning the water cold when you’re ending your shower.
2. Deep Breathing - A series of deep breaths informs your body you are not in danger and stimulates the vagus nerve. Deep breathing initiates the parasympathetic nervous system by releasing acetylcholine and GABA. One recommended method is alternate nostril breathing.
Studies have also demonstrated that individuals suffering from depression, anxiety, and chronic pain experience a remarkable improvement in symptom severity after participating in regular mindfulness meditation training.
3. Yoga or Exercise - Your body was not built to be sedentary, staring at a computer or phone screen for 8+ hours a day. Your body was built to move and when it moves, GABA is produced and the vagus nerve becomes more active.
4. Social Connection - Bad thoughts are stressful, and as we learned before, stress is directly tied to the health of your gut. The warm feeling that we get from interacting with friends, loved ones and our community can foster positive emotions. There was an extensive study done by Dan Buettner called Blue Zones where he found the five communities in the world with the highest rates of centenarians and strong social connections was one of the common themes.
5. Laugher or Vocal Work - The vagus nerve passes through the vocal cords and the inner ear, and the vibrations that singing produces are a simple way to activate the vagus nerve. Now, I have not been blessed with beautiful vocal cords, so I won’t subject anyone to my singing. So I throw on some stand-up comedy to get those muscles in my throat, neck and lungs activated.
6. Drink Water & Eat Nutrient Dense Foods - Your gut loves water. Additionally, nutrient-dense food provides the building blocks of key neurotransmitter production. Serotonin production begins with tryptophan, which can be found in poultry (preferably sourced locally), nuts, pumpkin & sesame seeds, spinach, milk and eggs. Dopamine production begins with tyrosine, which can be found in fish, avocado, almonds, squash, pumpkin seeds and wild rice.
So to wrap this up, a healthy vagus nerve is essential for the proper communication of messages between your gut, major organs and brain. The healthier it is, the healthier we are, both physically and mentally. If you feel like some of the warning signs above sound familiar, try implementing a few ways to stimulate the vagus nerve, get it firing all those neurotransmitters, keep that connection between gut and your brain nice and healthy and reap the rewards of good health!
Note: This information is meant to provide you with some tools to improve your health and well-being. Any changes to your daily routine should be implemented gradually. Please talk to your doctor or a licensed healthcare professional before making any drastic changes to your daily habits.