How can yoga improve gut health? The answer lies in the Vagus nerve that connects the brain to the Enteric Nervous System in the gut. Read on
The human brain doesn’t come with an owner’s manual. This is not my declaration, but a few PhD doctors and researchers said so. And I would like to believe them because I sure enough haven’t found a manual for mine. Thankfully, it manages to operate on auto-pilot mode, but I dread to imagine what it would be like if it did not. And to top it all, I am told that my body has not one but “two brains”. In the course of my yoga study and teaching, I discovered that two intelligence units operate within my body. Apparently these two units are fast friends, constantly communicating and updating each other of all the drama that goes on in our body.
Like many I know, I live up in my head on most days. Hence believing the brain was inside my head was fairly easy. But turns out this other brain, this “undercover agent” as I like to call it, is nestled away nicely in the wall of our gastrointestinal system, stretching from the lower third of the oesophagus right through to the rectum.
Imagine a whole web of sensory, motor and interneurons in our GI Tract constantly monitoring the situation and sending signals to its partner in crime further up the spinal ladder. Give a welcoming round of applause to our friend – the “little brain” medically also known as the Enteric Nervous System (ENS) located in our gut.
This gives a proper contextual framework for phrases such as “listen to your gut/ trust your gut” or “butterflies in the tummy”, does it not? However, this little brain is not so little after all. It comprises of two thin layers of more than 100 million nerve cells lining our gastrointestinal tract and its main function is “to control digestion, from swallowing to the release of enzymes that break down food to the control of blood flow that helps with nutrient absorption to elimination” as explained by Jay Pasricha, MD, director of the Johns Hopkins Center for Neurogastroenterology
Why is this small brain/ gut brain so important?
Because it talks to the big brain, relaying and receiving all kinds of crucial information through the neurons in our gut. Research is proving the role it plays in triggering major digestive issues such as Irritable Bowel Syndrome (IBS), constipation, bloating as well as chronic inflammation through release of pro-inflammatory proteins called cytokines.
It is now being understood that sub-optimal functioning of the GI tract can cause this gut brain to release several messages to the big brain, signalling imbalance in key hormones, especially serotonin, which is connected to our mood, digestion, well-being and happiness.
Here is the most interesting fact: Although produced in the big brain, approximately 90% of our body’s total serotonin is located in our gut/ GI tract, where it regulates intestinal movements. This piece of information is crucial and may give some clues as to the kind of dialogue that goes on between these two brains within our system.
What facilitates this dialogue between the two brains?
Clearly these two don’t have the luxury of meeting in a coffee shop or over a business lunch. They need to act fast and need a conduit that is ready to receive and transmit information within nanoseconds.
We now welcome the Vagus Nerve, one of the major conduits of information between the big and small brain. It is the 10th cranial nerve and the longest-running nerve of the autonomic nervous system (ANS). “Vagus” derives from the word “wandering” and for good reason. It begins at the brain stem and travels all the way to the colon, passing through all major organs and areas in the neck, chest and abdomen. It is responsible for calming down our system so that all the digestive processes happen efficiently.
This Vagus nerve, in the course of its sight-seeing expedition along our body, captures critical data and transfers gut and microbiome-related information back to the brain. It is an important element in the gut-brain axis (GBA) which allows for a two-way dialogue between the central (brain and spinal cord) and the enteric nervous system (gut), linking emotional and cognitive centers of the brain with intestinal activity.
What is the relevance of yoga in maintaining an optimal dialogue between these two?
When the Vagus nerve functions well and is properly stimulated, many important functions such as heart rate regulation, digestion and overall relaxation is taken care of smoothly by the body. It calms us down sufficiently so that all the smooth muscles in our gut can function well and the body finds a balance between what we bring in and what we need to let go of.
However, when the Vagus nerve becomes weak or loses its vagal tone, the first thing to be impacted is this clear channel of communication between the gut and the brain. Essentially, this important link between our intelligence units gets destabilized and they don’t talk any more. At least not clearly enough.
It’s like a cold war within our system, and with no mediator available to bridge this communication gap. And I cannot stress enough on the importance of yogic techniques in strengthening and toning the Vagus nerve. It appears that the ancient seers and yogis knew and fully understood the intricate functioning of this nerve and all aspects of yoga practice help in developing and strengthening it.
There is substantial research on the positive impact of yoga therapy and yogic practices on healing the Vagus nerve. Link to one such work is here which includes input from some top experts, especially Stephen W Porges who has done some ground-breaking work in this field.
A combination of postures, specific breathwork as well as chanting and sound therapy can go a long way in improving the health of our Vagus nerve.
Below are a few techniques outlined to bring this about:
While the entire asana practice is designed to calm down our nervous system, improve vagal tone and improve overall well-being, certain postures help particularly well:
1. Inversions such as Sarvangasana (Shoulderstand)/ Halasana (Plough pose)
2. Backbends such as Chakrasana (Wheel Pose)/ Ushtrasana (Camel Pose)
3. Forward folds such as Paschimottanasana (seated forward fold) or Janu Sirsasana (head to knee forward fold)
While inversions stimulate the neck/ throat region which is where the Vagus nerve begins, backbends and forward folds help is toning and facilitating a better connection between the brain and the gut. All three categories of postures help bring more awareness into the spine, spinal cord and the gut, enabling pranic and blood circulation to these areas.
Correct breathing is considered to be one of the simplest yet most effective ways to tone the Vagus nerve. Most of us breathe incorrectly, and this is where most problems begin. Since this nerve passes through our thoracic and abdominal regions, full, deep and correct breathing is critical. Below are two techniques that improve the quality of our breath as well as stimulate the Vagus nerve.
Deep abdominal breathing (also known as diaphragmatic breathing)
One of the most therapeutic ways to heal the Vagus nerve is also through sound. Chanting, singing and humming are highly effective tools to engage the vocal chords which are innervated by the Vagus nerve. Below two yogic techniques are used frequently to calm down the system in a traditional yoga practice.
** Get in touch with a certified yoga teacher to take you through these sound related techniques.