How are the gut and brain connected?
Artists: Ashley Valenton & Michael Buffardi
Research: Ashley Valenton
How are the gut and brain connected?
Questions
You all know about the brain in your skull, but do you know about the second, smaller brain in your gut?
This is referred to as the enteric nervous system (ENS), and is made up of millions of nerve cells that line your gastrointestinal tract and communicate with the brain (The Brain-Gut Connection).
Introduction to gut-brain axis
The ENS communicates with the brain through the “gut-brain axis.” They are connected through nerves in your nervous system, one of the biggest nerves being the vagus nerve, which sends signals in both directions (Robertson 2018).
How does the vagus nerve work?
Once we digest food, it travels through the GI tract and eventually gets to our small intestine, which is covered in villi (Duke University 2018). Intestinal villi cover the inner lining of our intestine like a bunch of
little fingers, grabbing and absorbing the nutrients from food that we’ve just eaten (Verywell Health). Villi are made up of cells, just like everything else. However, one cell plays a key role in the gut-brain connection: the neuropod cell. The neuropod cell is connected to our vagus nerve. They tell the vagus nerve when they sense certain nutrients or bacterial byproducts, and the vagus nerve sends that information up to the brain.
Wait - what’s in my gut?
There’s bacteria in your gut - but don’t worry, they are good bacteria! They are referred to as gut microbiota. Gut microbiota communicate with the brain in several ways, but we will focus on something familiar: neurotransmitters (or chemicals that communicate with the brain).
Our gut microbiota produce neurotransmitters such as serotonin and GABA (Robertson 2018). GABA blocks nerves from communicating with one another and is known for producing a calming effect and controlling one’s anxiety during stress (Cleveland Clinic). Serotonin is known as our “feel good chemical” and influences our focus, our emotions, the quality of our sleep, and more! And guess what - 90% of it is made in our gut (Cleveland Clinic).
The Immune System
Since the gut controls what is passed into the body and what isn’t, the gut contributes majorly to the immune system. For example, LPS (lipopolysaccharide) is an inflammatory toxin that can cause inflammation, which is associated with brain disorders such as depression, dementia and schizophrenia (Robertson 2018).
What should we eat to ease our brains?
We should eat: Probiotics and prebiotics, omega-3 fats (i.e. fish), fermented foods (yogurt, cheese), high-fiber foods (whole grains, nuts), polyphenol-rich foods (cocoa, green tea) and tryptophan-rich foods (turkey, eggs)! All of these once consumed increase good bacteria in your gut and improve brain function (Robertson 2018).