Did you know you have two brains? One you already know of, the one in your head. There is also the one residing in your belly – your gut/GI-tract, also named the “second brain”. You might never have thought of your gut being anything else than a “feeding tube”, processing food, breaking it down and making nutrients available for the rest of your body. But this amazing tube has a lot more to say on how to run your system.
We already refer to the gut when it comes to our daily life: “Butterflies in your stomach.” “Gut-wrenching.” “Makes me feel nauseous.” “Lump in my throat.” “I have a gut feeling.”
And we all know how bad we feel when we have an upset stomach. It is also common knowledge that stress and anxiety has unwanted effects on our GI-tract. But little did we expect how much we actually are run by our guts.
Research has shown that the gut contains more than 100 million neurons (nerve cells), that’s more than all the nerves in your spinal cord and your other body tissues together. This Enteric Nervous System (ENS) is located under the mucosal layer and in between the muscle layers in the gut.
The Vagal nerve, connecting your gut brain with your head brain, actually transports more information to the brain from the gut than the other way around. It is also an highly active endocrine (hormonal) organ, secreting more than 30 different neurotransmitters (signal substances), and variety of hormones to communicate within it self and with the other organs and tissues within the body.
Substances like dopamin, serotonin, glutamate and norepinephrine were believed to be products of the brain and the spinal cord only, but have now been found in the gut.
The ENS produces about 95 % of the body’s serotonin, a neurotransmitter associated with mental health. One of the theories explaining depression suggests there is a lack of Serotonin in the brain and hence came the Selective Serotonin Reuptake Inhibitors (SSRI) to solve the problem. A common adverse effect is gut issues, probably related to changing the balance of this chemical in the gut.
People suffering from Irritable Bowel Syndrom (IBS) has been shown to have raised levels of Serotonin in their gut tissues, and this could be a part of the puzzle explaining this disorder. A kind of “mental illness” of the second brain.
It seems like the serotonin from the gut also can have a part in the development of autism, a developmental disorder that affects how kids interact and communicate. Many kids with autism also have GI issues and food allergies and sensitivities. It seems that the same genes that codes for the development of synapses (the connections between nerves) in the brain are responsible for the growth of the gut brain as well.
The GI -tract also has a big role to play in our feelings of happiness and comfort. There are cells secreting and recieving “feel-good” hormones, e.g. endorphines and enkephalins, in the wall along the lenght of our food tube. They relay feelings of happiness, joy, satisfaction and pain relief.
It also produces chemicals resembling bensodiazepines, a class of drugs used for anxiety disorders and for calming the body.
These together are responsible, at least partly, for your that warm gut feelings.
The gut and the brain communicates through the nervous system, the hormonal system and also through the immune system.
A big part of our immune system resides in the gut and bacteria, believe it or not, are a part of the immune system as well as important players in the gut brain.
Some of the micororganisms in our gut release neurotransmitters that sends messages to our brain through the vagus nerve. Others take care of the break down of foods and the building of nutrients that are vital for us and we couldn’t get without their help.
So it seems we need the right bacteria in our guts to keep everything running smoothly, including our head brain, immune system and hormonal system.
This is a growing field of research, neurogastroenterology, looking for how the connections between our gut brain and head brain affect neurodegenrative diseases like Alzheimers and MS and neurodevelopmental disorders like ADHD, autism spectrum disorders etc.
It seems that our second brain is far more important in the development of disease and disorders than we ever could expect.
It might be that gut dysbiosis (dysregulation in the bacterial environment of the gut) is the culprit for many diseases and will be the first thing that is looked for and treated.
When you think about it, it doesn’t seem that far fetched that how we live and what we eat will affect our health. Not only does the food need to be nutritious for the cells in our bodies, we need to feed the bacteria in our guts in the right way as well.
We actually “know” what to eat and how, but we don’t know how to listen to the signals any more. We are disconnected from our environment and hence the food we eat.
I suggest you pay attention when you eat next time, hone your gut intelligence. How does it feel when you eat? How do you feel afterwards? Full or still hungry? Warm and happy or upset and painful? Are you craving certain foods (sugar is not included here, because of it’s addictive properties)?
Also trust your gut feelings when it comes to make decisions. Do you feel tight in your stomache when saying yes to that job? Do you actually want to add another house project in your free time?
What does your gut brain say?