“Your gut is your second brain.”
Why do we say that? If our brain is our first brain and our gut is our second brain, which one is the main brain? Does one effect the other and vice versa?
There is a very intimate connection between your gut and your brain starting all the way back to when you were just a few cells in the womb. The nervous system is the very first system to develop in the body and it actually hardwires itself into your gut through what is known as the enteric nervous system (ENT). The ENT plays a large role in relaying information to the brain about what’s happening in your gut, which helps control secretions and blood flow to allow you to properly digest and absorb your food.
The amazing part about your enteric nervous system is that even though it is richly supplied with neurons that are connected directly to your autonomic nervous system, it is able to operate independently from it, like a system of rogue neurons that want to play by their own rules, in terms of digestion. Hence why your gut is called your Second Brain.
I remember my first time ever giving a presentation, where I was going to have to speak publicly in front of 50 people in my class. I honestly can’t remember the topic, but I remember the feeling.
“Knees Weak, Arms Sphaghetti.” — Eminem
I had the “butterflies” in my stomach and kept myself relatively close to the trash can because I was feeling so nauseous. My hands constantly shook during the entire presentation and I looked at my notecards the entire time.
Maybe you can relate to this experience?
You may be surprised to learn that there are actually NO BUTTERFLIES in your stomach, it’s actually a neurological response from your brain, into your second brain. This intimate relationship between the brain and the enteric nervous system is what is known as the Gut-Brain Axis.
Interesting research has been done that uncovers the vital influence the gut microbiome has over your emotional state through the Gut-Brain Axis. Changes in the gut microbiome from chronic inflammation, stress, antibiotics, high carbohydrate diet, high sugar intake, or high toxic load from food and environment has been shown to negatively impact the brain. [R]
These changes in our microbiome can influence the central nervous system and has been shown to even influence our behavior. It has also been shown to activate the fight or flight response, which becomes a slippery slope of chronic stress and inflammation, which can continue to make matters worse.
Inflammation is a natural response from the immune system to a threat, injury, or invader. It’s meant a short term response not a long term solution. Inflammation that becomes chronic begins to damage our body, especially if the inflammation is throughout our body. Chronic inflammation is thought to be the main cause of many chronic diseases we face today.
Chronic inflammation in the gut can lead to a condition known as leaky gut, where the “pores” that line the gut get swollen and inflamed, allowing them to expand, letting large substances pass through unfiltered and undigested. When these substances get through the gut directly into the bloodstream they create havoc throughout the body. This is thought to be one of the main factors behind autoimmune conditions and chronic inflammatory conditions.
Leaky gut has also been shown to cause a leaky brain. The blood vessels in the brain contain a protective barrier that insulates the brain from harmful substances that could be detrimental. Research has shown that leaky guts release antibodies that also open up the blood-brain barrier, allowing harmful substances to cross directly into the brain, creating tremendous amounts of inflammation. [R] This can lead to brain fog, headaches, anxiety, fatigue, and dramaticaly reduce brain performance.
It’s also important to know that your gut houses and stores a large number of neurotransmitters. Roughly 90% of serotonin, your happiness neurotransmitter, is housed and stored in the gut. The gut also is home to dopamine, glutamate, norepinephrine, GABA, and nitric oxide. Inflammation in the gut will affect the production of these neurotransmitters. These neurotransmitters are critical for the brain to do its job well.
Imagine trying to do a job that requires at least 20 people to do the job effectively and on time, but instead of 20 people, you got 10. Do you think you would be able to do your job effectively and timely? Maybe, but most likely not. Your brain may be able to get by, but it won’t be able to do a good job. For instance, low levels of the neurotransmitters serotonin and dopamine can lead to depression.
Your gut also creates the essential trophic factors for neuroplasticity such as brain-derived neurotrophic factor (BDNF), synaptophysin and postsynaptic density. Trophic factors are special proteins that stimulate the growth and production of new brain cells. When the gut has trouble producing trophic factors, neuroplasticity (the ability of the brain to adapt and change) gets suppressed. Without these trophic factors the brain remains rigid and lacks adaptability.
Another key connection that links the enteric nervous system to the brain is the Vagus Nerve. The vagus nerve is not what allows you to stay up late, overpay for drinks, eat at buffets, and gamble. It’s the only cranial nerve that extends directly from the brain and goes all the way down to supply and innervate your vital organs. The Vagus Nerve is called the “wandering nerve” because it’s the only cranial nerve that exits the skull and continues down past your neck into the gut.
There is some amazing research being done on Vagus Nerve Stimulation, which is where researchers artificially stimulate the activity of the vagus nerve typically through electrodes of a patch that is able to stimulate through the skin. It’s essentially hacking into the vagus nerve.
Here’s just how powerful the vagus nerve is for your gut and brain. Electrical stimulation of the vagus nerve in several studies has been shown to reduce inflammation in the gut, improve gut motility, calm the sympathetic nervous system, and improve immune function. [R] There are also studies being done to review its application for treating issues such as depression and anxiety. [R]
You can see that there is a direct connection between your gut and your brain in more ways than one. So pay attention to what you put in your mouth because it will influence brain performance and even your mood.