Did you know you have a second brain?

Author: Kaylee Dunbar   Date Posted:2 February 2016 

We all know that our brain is the key to life, it orchestrates all of our vital bodily processes such as interpreting and processing information, regulating breathing and heart rate, maintaining blood pressure and releasing various hormones. But guess what…?! 

Did you know that we also have a second brain?!  Mind blown… (Don’t worry you have a second one!)


Our second brain

Like our primary brain our second brain also has its own nervous system called the enteric nervous system. It is located in the lining of the oesophagus, stomach, small intestine and colon and is estimated to be around 9 meters long.  Although the enteric nervous system can work independently it also communicates information from our gut to our primary brain via the vagus nerve, a nerve that stretches from the brain stem to our stomach, our largest cranial nerve which transmits sensory information. 

The vagus nerve is also connected to various other organs in the body such as the heart, oesophagus and lungs. The vagus nerve contributes to mood alterations, feelings of fear, anxiety and nervousness when we are under stress because it communicates information from the enteric nervous system to our primary brain which is able to express emotions! 

So the next time that you feel those butterfly’s in your stomach you will know that the vagus nerve is behind this! The vagus nerve is also responsible for creating feeling’s of satisfaction after we consume comfort foods when we feel stressed. Comfort foods such as hot chips or chocolate tend to be high in fat, which is detected by fat receptors in our digestive system.

The vagus nerve then transmits signals from your digestive tract to your brain to tell you that you are full and content. So as you can see there is constant communication between both of your brains!


A bundle of nerves

The enteric nervous system is made up of approximately 100 million neurons that send nerve impulses to our primary brain so that the two systems can communicate. To give you an idea of the significance of 100 million neurons; this total quantity is more than what is found in both the spinal cord and peripheral nervous system! 

These neurons are embedded throughout the entire digestive tract starting from the oesophagus and ending in the anus. It is these neurons that support our digestive processes to break down food, eliminate waste and maintain the correct pH balance in our digestive tract to assist with the absorption of nutrients. In addition to these neurons the digestive system is also supported by living microorganisms called probiotics.

They keep our good bacteria balanced in our digestive system minimising symptoms of bloating, constipation, diarrhoea, heartburn and indigestion.



Happy Guts

The enteric nervous system has always been known to be involved in controlling our digestion but recently researchers have began to explore the possibility of this system having the ability to impact on our mood. This is because interestingly enough our enteric nervous system like our primary brain also produces approximately 40 different hormones and neurotransmitters, some having the ability to impact on our mood such as serotonin, dopamine and noradrenaline.

What’s interesting is that recent research has demonstrated that probiotics have shown to have the ability to improve our mood. The mechanism of action associated with this mood change is not entirely known, however researchers have hypothesized that probiotics may reduce inflammation or  gut permeability. It was also speculated that because probiotics stimulate the growth of intestinal bacteria that this enhances our tryptophan concentrations. 

Tryptophan is one of the precursors that is required to form the hormone serotonin which supports a healthy mood. Interestingly enough, the second brain contains 95% of our body’s serotonin receptors so when we are feeling stressed this often also affects our digestive function leading to symptoms of diarrhoea and or constipation.


So let’s take a look at the study that confirms these findings!

A triple-blind, placebo-controlled, randomised, pre and post intervention assessment design investigated 40 healthy participants without a current mood disorder. Participants were allocated randomly to receive either a 4-week powdered probiotic multistrain supplement called Ecologic Barrier, consisting of eight different probiotic strains (Bifidobacterium bifidum W23, Bifidobacterium lactis W52, Lactobacillus acidophilus W37, Lactobacillus brevis W63, Lactobacillus casei  W56, Lactobacillus salivarius W24, Lactococcus lactis W19 and W58) or a placebo powder. 

Participants who received the 4 week probiotic treatment experienced less aggressive or distressing thoughts when put into a sad mood compared to the placebo group. Researchers have concluded that this is the “first evidence that the intake of probiotics may help reduce negative thoughts associated with sad mood.” 

So there you have it, mood can be influenced by both of your brains!

Written by Kaylee Dunbar

Kaylee has a Bachelor of Health Science in Naturopathy and an Advanced Diploma as a Pharmacy Technician. Her passion for natural medicine first began when she worked as a pharmacy technician and saw how many people were looking for more ways to support their health. This sparked her interest in learning how to support health using complementary medicine alongside orthodox medicine. Her main objective is to inspire and educate others about the benefits of natural medicine and how to apply it to everyday life.

Although Kaylee is passionate about natural medicine she does not mind a glass of red wine every now and again!