It’s becoming quite popular, especially in holistic circles, to hear the phrase “gut-brain” connection. But what exactly does this mean?
There are many factors that influence the gut-brain connection but my focus in this article will be on the Vagus Nerve. Anatomically, the Vagus Nerve is the 10th cranial nerve and is the longest pair of cranial nerves in the body; hence its Latin root meaning “wandering” or “vagabond.” It begins in the medulla oblongata at the stem of the brain and runs through the neck, thorax, and into the abdomen. One of the main functions of the Vagus Nerve is to transmit the sensory information from the brain to all the organs it connects to.
The Vagus Nerve is responsible for many complex processes that occur throughout the body, mostly via the Parasympathetic Nervous System, which is the “rest and digest” system that eases our bodies by slowing down heart rate, lowers blood pressure, and relaxes our intestinal muscles to aid in digestion. Hence, the connection of the Vagus Nerve with digestion and assimilation and the effects on the body when this connection is damaged or malfunctioning.
Stress presents in many different forms; mental/emotional, physical, environmental, existential. We are bombarded on a daily basis with all different forms of stress, and this impacts us more that we realize. Our body’s stress response raises steroidal hormones (epinephrine, adrenaline, cortisol), and this triggers the Sympathetic Nervous System (known as “fight or flight”) to override the Parasympathetic Nervous System, over which the Vagus Nerve communicates. When this happens, the Vagus Nerve can respond by sending “messages” resulting in heart palpitations, stomach bloating, diarrhea or loose stools, shortness of breath, and anxiety/panic attacks.
However, it’s a two-way street, because irritation and/or damage of the GI tract will also have a very negative impact on the Vagus Nerve and its functionality, sending “wrong” messages back to the brain. The majority of signals along the Vagus Nerve are actually efferent, meaning communication is from the peripheral organs back up to the brain. A fascinating article cited in Psychology Today highlights the results of a Swiss study in which the researchers disconnected the afferent Vagus Nerve fibers of rats in the gut (these send signals from the brain to the gut) so they could look ONLY at the one-way communication from the gut up to the brain to access fear, anxiety, and neurochemical changes in the brain. They determined, through behavior, that the rats that had no Vagus Nerve efferent connection from the gut to the brain had less fear of open spaces and bright lights than those rats with a fully functioning Vagus Nerve. So innate fear was less, partly due to lack of sensory perception (the rats didn’t have that “gut” instinct). But, learned fear levels lasted longer because they didn’t have the 2-way communication to turn off the learned fear timely.
Another key finding of this study is that neurotransmitters, particularly GABA, Acetylcholine, as well as hormones, also affects the proper communication and function of the Vagus Nerve from the gut to the brain, which has a direct impact on mood, learning, and stress levels. More research is needed, but this study clearly determines the impact of the gut-brain and brain-gut connections via the Vagus Nerve. So, the next time you say you have a “gut” feeling about something, trust your feelings—it’s a lot more scientific than you may think!
As a health coach, it’s very common to see symptoms of depression, anxiety, panic attacks, and sleep problems, to name a few, decrease as my clients begin to heal their guts. If you wish to learn more about how I can help you repair your gut-brain connection, please click here to book a FREE 30-minute consultation. I look forward to guiding you on your healing journey!
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