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What Is the Gut-Brain Connection?

Posted by Brad Dennis, Ph.D. on

What Is the Gut-Brain Connection?

Have you ever had butterflies in your stomach? Did you recognize it as such and learn how to recognize it every time? Many of us had those moments when we simply knew that something needed to be done because “our gut told us so”.

Even from these simple rationalizations we can see just how much our emotions are tied to our stomach and even when there wasn’t any scientific proof behind it, people knew that these two were closely connected. When we feel shy, in love, angry, dissatisfied or excited, we feel these things in our stomach. Today, there is proof of gut bacteria brain function and scientists have named this phenomenon the Gut-Brain connection.

One of the first amazing discoveries that was instrumental in explaining the Gut-Brain connection is the fact that our body is not a single organism, as we thought before. Our body is always a host to a trillion different organisms. Some 90% of our body is, in fact, made up of these organisms called “microbiome” and a lot of them are located in our gut.

We are more insects than human

As I mentioned earlier, our body has more bacteria cells than human cells. This whole entity of bacteria is located all over our body, but a lot of it is located in our gut and they can affect our health in many ways. These important new insights have allowed us to look at our gut as more than just a system of organs that regulates digestion.

Now, it’s seen as one of the most important factors in regulating our immunity and controlling inflammations. When the gut is healthy, it means that it has a good balance of bacteria, but the proportions are different for every person. The diversity of bacteria in our gut is what keeps us in good health, and if you destroy your natural balance, it will lead to dysbiosis, which can lead to a number of diseases.

In the light of these discoveries, a lot of research has been done on microbiome and its effects on various diseases, no matter if they are brain disorders, autoimmune diseases or gastrointestinal diseases.

Our gut is our second brain

Our gut has its own ENS (enteric nervous system) that contains around 100 million nerves, which can be found in our gut’s lining. Through it, the gut microbiota affects both our psychological and physical health. The ENS has many similarities to our central nervous system, because it develops from the exact same tissues. This is why it’s often referred to as “the second brain”.

The ENS is not capable of thought processes like the brain, but it constantly maintains communication with our brain and this information going back and forth helps our body function properly. This has shown that ENS has a lot of effect on what we endure emotionally, if we are having troubles with our gut. Things like IBS (irritable bowel syndrome), bloating, stomach unrest, diarrhea and constipation are related depression and anxiety.

Although our brain is the main decision maker, the gut sends valuable impulses that can help it decide how to act, feel or invoke emotions.

Probiotics can help reduce anxiety and affect emotions positively

There are a couple of studies that have concluded that probiotics affect gut microbiome positively and help reduce anxiety. One of those studies used an MRI to see how gut microbes affect our mind and the underlying brain mechanics. The study made a group of people take probiotics twice a day for 4 weeks, while others took milk without probiotics.
The goal was to see how the brain would react to these things, and those people who took probiotics had changes in parts of the brain which are used for emotional processing. This study has shown proof that gut microbiome changes can help us process emotions better. The same rule applies both ways.

If a person is feeling depression or anxiety he or she might also suffer from nausea, stomach problems, bad digestion etc. Taking care of gut flora is highly important for a person’s health, as it can help remove many underlying mental issues.

Prebiotics have an important role as well

Given the fact that that the amount of stress we have can be directly related to the pain in our gut, a group of scientists gathered to do a study with the goal of proving the correlation between gut microbiota and the level of stress. They did this by giving prebiotics to the people involved in the study.

When we compare prebiotic vs probiotic, prebiotics are simply sugar molecules. The good bacteria in our gut absorb them, break them down and use them for multiplying. This means that by taking prebiotics on a regular basis, you’ll encourage an increase in good bacteria levels, which will further regulate your stomach health.

From this, we can conclude that prebiotics have value as much as probiotics and that they can help our stomach feel healthy, hence make us feel less stressed. Some even compare them to antidepressants, considering how positively they affect people. It is recommended to take them regularly, even if you don’t have stomach problems, in order to keep the good bacteria at a healthy level.


Taking probiotics can help a person greatly improve his overall mood. A person can feel more resilient. This is especially important for people who’ve had problems with their gut in the past or had medical procedures done on their stomach.


The Brain-Gut Connection: How Gut Bacteria May Treat Depression
Your Gut Bacteria Affects Your Brain Function, Study Confirms
The gut-brain connection
The Gut-Brain Connection, Mental Illness, and Disease



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