From butterflies in your stomach, bathroom visits prior to presentations and being unable to digest anything after a break-up: we’ve all been confronted with the fact that the gut and the brain are intertwined in a complex, yet somehow noticeable way. Research is now unfolding how this takes place and the manner by under which the connection between the gut and the brain is established. Bearing this in mind, you better take a deep breath because things are about to get really science-y in here ...
Zooming in on the communication system — or (gut-brain) axis — between the gut and the brain, it appears that the gut and the brain are connected both physically and biochemically through (amongst other things, but most importantly) the vagus nerve and the nervous system. The nervous system is characterised by so-called ‘neurons’ that tell your body how to behave. As they are predominantly located in your brain, it was initially thought that the brain determined human behavior. For this reason, over the last decennia or so, the notion of free will was brought into question. It was not something researchers could pinpoint physically, after all.
Nevertheless, I often questioned, how was it that I could have a gut feeling about something? Or, how was it that I had to make some gut-wrenching decisions that certainly didn’t feel like what was then for my brain cells to figure out?
Well, as it turns out, the brain is not the only place neurons can be located. Your gut contains an incredible amount (circa 500 million) of neurons, which are all connected to the brain by virtue of the nerves that together constitute the central nervous system. As a result, research can now pinpoint, stress is not only related to the brain, but it inhibits signals sent through the vagus nerve, causing gastrointestinal problems in the gut. Hence, it appears that people who suffer from IBS have a reduced vagal nerve function, which could be related to stress.
In both theory and practice, your gut and brain are connected through chemicals called neurotransmitters. They control feelings and emotions. As a case in point, the most well-known neurotransmitter ‘serotonin’ contributes to feelings of happiness. Though the production of neurotransmitters like serotonin has always been thought to have taken place in the brain, it now turns out that they are produced by your gut cells (and the microbes that together constitute them). As such, the neurotransmitter gamma-Aminobutyric acid (GABA) is also produced in the gut. This neurotransmitter helps control feelings of fear and anxiety. Interestingly, studies have shown that probiotics can increase the production of GABA. Bearing this in mind, it appears that the trillions of microbes that live in your gut not only have a direct effect on how your brain works, but also the other way around.
This, in turn, follows from the fact that the gut-brain axis is connected through the immune system. As we now know, auto-immune diseases are long on the rise. This is, because, if your immune system is switched on for too long, it leads to inflammation, which in turn is associated with things like Alzheimer’s disease and depression. When your body is inflamed, an inflammatory toxin (Lipopolysaccharide) is made by gut bacteria and released into the blood via a weakened gut barrier (that is otherwise known as leaky gut).
Both the good and bad news is that what you eat can either reduce or aggravate inflammation (I learned the hard way!), going so far as to heal or exacerbate leaky gut (yikes!). Especially Omega-3 fats and fermented foods (like yogurt, kefir, and sauerkraut) have shown to increase good bacteria in the gut. In turn, so have high-fiber foods (like nuts, seeds, and vegetables that contain prebiotics), polyphenol-rich foods (like cocoa, olive oil, and coffee) and tryptophan-inducing foods (like turkey, eggs, and cheese).
Bearing this in mind, it should come as no surprise that the non-processed Ketogenic Diet is often referred to as the go-to for better brain-and-gut health. After all, it is a big advocate (or avocado) of healthy fats (like kefir, cocoa, nuts, and cheeses) that together feed the types of bacteria which together function as psychobiotics for the brain — proving, once more, to what extent the gut and the brain are not only affected by but very much intertwined with one another.
Now, let’s avocuddle, because it appears both my brain and gut will benefit from it!
In case you want to satisfy the science nerd in you somewhat more, we recommend reading:
- Mind-altering microorganisms
- The emerging biology of gut–brain communication
- Vagus Nerve as Modulator of the Brain
- The Vagus Nerve at the Interface of the Microbiota-Gut-Brain Axis
- Microbial Glutamate and GABA Signaling
- The Neglected Endocrine Organ
- Chocolate, gut microbiota, and human health
Article written by Julia Kempi
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