The Gut-Brain Connection: What It Is and How Nutrition Affects It

The Gut-Brain Connection: What It Is and How Nutrition Affects It

If you’ve ever had a “gut feeling” about something that ended up being correct, science shows that it may have been more than just butterflies in your stomach. 

Indeed, our guts contain hundreds of millions of nerve cells that are connected to those in our brain. While the relationship between our brains and our guts has been well-documented for many decades, recent studies have discovered that these nerve cells can communicate with each other in a bidirectional way. 

This means that not only do nerve cells in our brains influence those in our gut, but the nerve cells in our gut also influence those in our brain! 

So, how do these nerve cells in our gut influence the rest of our body? Can they control how we behave just as our brains do? Let’s explore the gut-brain axis and what it means for gut health.

What Is the Gut-Brain Axis?

The gut-brain axis refers to the bidirectional communication between the enteric nervous system (ENS) in your gut and the central nervous system (CNS). This means that the nerve cells in your gut can influence your brain and the rest of your body. 

The discovery of this two-way signalling has led to a better understanding of how your gut microbiome influences your mental health. The neurons in your ENS have a significant influence on your mood, mental state, and overall happiness. Studies have also shown that your gut neurons can even cause depression. That’s why the gut-brain axis has garnered so much attention within the scientific community over the past few years. 

How Your Gut and Your Brain Are Connected

The neurons in your gut and those in your brain are connected both physically and through the use of neurotransmitters. Let’s take a look at how these two nervous systems communicate with each other to keep your body alive and healthy.

The Enteric Nervous System

The enteric nervous system (ENS) is a collection of 200 to 600 million nerve cells that line our intestines. These nerve cells are tasked with regulating digestion by managing blood flow, moving the gastrointestinal tract, and releasing acids that help break down food.

The ENS is connected to the CNS through neural pathways that connect the nerve cells in our intestines with those in our brain. This allows direct and instant communication between our “gut brains” and our real brains.  

The Vagus Nerve

The vagus nerve serves as the direct connection from your brainstem to your abdomen. It is an integral part of the parasympathetic nervous system (PNS), which helps regulate digestion, mood, and other bodily functions. It is in charge of reporting the state of internal organs to the brain. 

The vagus nerve is the physical connection between the gut and the brain. Think of it as an internal highway where information is sent from the GI tract to the brain via ​​afferent fibres. Studies on the vagus nerve have been instrumental in proving that the gut can send information to the brain. 


Neurotransmitters are chemicals produced by our bodies to regulate mood and other physiological and cognitive functions. One of the most popular neurotransmitters is serotonin, which has been affectionately referred to as “the happy hormone.” 

While most people understand the importance of this happy chemical in our lives, few know that over 90% of all serotonin is actually produced in the gut. That means that if you have an unhealthy gut, your serotonin production may be affected. This could impact your overall mental health and could even cause depression. 

Another essential neurotransmitter produced in the gut is gamma-aminobutyric acid (GABA). If serotonin is the happy hormone, then GABA is the relaxed hormone. These neurotransmitters are very closely linked to anxiety and depression and help us stave off feelings of anxiety and fear.

Your Gut and Mental Health

As we now know, the gut is very much related to the brain. But how exactly does this relationship work? Can having a bad diet actually cause mental health issues like anxiety and depression? Let’s take a closer look at the science.

Can Gut Health Influence Your Anxiety?

Yes. Your gut health can influence mental health problems like anxiety and even depression. As we now know, the ENS contains hundreds of millions of nerve cells that line our intestines. These cells carry out essential functions, like releasing the “happy hormone” serotonin. If you have poor gut health (known as “dysbiosis”), your ENS won’t be able to carry out its functions optimally. 

Science shows that a healthy gut helps keep your ENS in homeostasis. This allows the neurons in your gut to perform the job they’re supposed to so that you can stay happy and healthy. 

Can Improving Gut Health Help Treat Anxiety?

Science says yes. We know that there is a causal relationship between our gut health and our mental health, thanks to a study involving vagotomized mice. In this study, the vagus nerve (the superhighway between the gut and brain) was removed from a group of rats in order to study if the same cognitive benefits can be appreciated after improving their gut health. 

The study concluded that non-vagotomized rats experienced significant improvements in symptoms of anxiety and depression after consuming a diet rich in prebiotic and probiotic foods. However, the same results were not observed in vagotomized rats, thus confirming the importance of the vagus nerve in sending information from our guts to our brains. 

So, if you are experiencing symptoms of anxiety and depression, focusing on improving your gut health may help you relieve some of them.  

Foods to Eat for a Healthy Gut-Brain Axis

If you are looking to improve your mental health, focusing on your diet can be a great place to start. When your gut microbiome is in dysbiosis, you can experience a whole host of problems, including digestive issues, autoimmune diseases, and even cancer

Luckily, improving your gut health can be as easy as changing up your diet. Here are some great foods that you should regularly consume for a healthier gut and a happier brain:

  • Fermented foods. These foods are naturally probiotic and can help introduce new species of healthy bacteria to our gut. Up your intake of kefir, miso, sauerkraut, kombucha, tempeh, kimchi, and other fermented foods.
  • Prebiotic foods. The bacteria in our guts need plant fibre to thrive. Increasing the number of fresh fruits and vegetables in your diet can lead to a more balanced microbiome.
  • A variety of vegetables. Plant diversity is the number one indicator of a healthy gut. Instead of eating the same veggies all the time, focus on eating a wider variety to keep your gut bacteria happy. 
  • Nuts and whole grains. These yummy foods are packed with plant fibre, which will help feed the bacteria in our gut. They also help improve digestion, which is another sign of a healthy gut!

Next time you go to the supermarket, keep these foods in mind for a healthier gut!

Order Your Gut Health Test Kit Today To Get Started

Our gut microbiome is so much more influential than most of us realize. Not only does it help with digestion and nutrient absorption, but it can also help us stay happy and mentally healthy. Luckily, improving our gut health is easy by making healthier changes to our diet.  

And if you want to have an even easier time improving your gut health, you should order a Gut Health Test Kit today to get a custom report on the status of your gut microbiome. At OSbiome, our gut tests come with 15 proprietary health scores and a custom game plan for improving gut health. If you want step-by-step instructions for a healthier gut, order your kit today!