You may have heard the gut referred to as the “second brain”. But do we really have a second brain? Yes, we do!
What is commonly called the “second brain” is technically called the enteric nervous system (ENS). The ENS is a complex network of neurons and supporting cells that are found in the walls of the gut.
This complex network of neurons, neurotransmitters, and other signalling molecules is similar to those found in the brain. Not only that, the brain and gut are in constant communication through a bidirectional communication network that involves the immune system, the endocrine system, and the nervous system.
“When we talk about the gut-brain axis, what we’re talking about is a very intimate connection between the composition of our microbiota and our brain activity,” explains Gianfranco Grompone, Chief Scientific Officer at BioGaia.
How your gut bacteria affect your mental health
The gut microbiota is a community of microorganisms that live in your gut, consisting of bacteria, viruses, fungi, and other organisms. These microorganisms play a crucial role in your health. The bacteria in your gut not only aid with digestion and absorption of nutrients but also help you maintain a healthy immune system by providing protection against harmful pathogens.
New research shows that the gut microbiota can also affect our mental health. We all know that chronic stress and anxiety impact mental health, and, often, the tummy is the first place we feel stress in the body. As we share in a previous post, stress triggers the release of cortisol, a hormone that can disrupt the gut microbiota and cause inflammation in the gut.
A healthy gut microbiota is important for producing neurotransmitters such as serotonin and dopamine. Approximately 90% of serotonin and 50% of all dopamine in your body are produced in your gut, so it's not difficult to see how your gut health can impact your brain and, therefore, your mental health.
For example, serotonin regulates a number of bodily functions, including mood, appetite, and sleep. In the brain, serotonin is known to play a key role in regulating mood.
In the gut, serotonin plays a role in regulating gut motility, secretion, and sensation. It also helps coordinate muscle contractions and relaxations and regulates the secretion of digestive enzymes and fluids.
It’s all connected
Research has shown that changes in the gut microbiome can affect the production of serotonin and dopamine in the gut, which in turn can impact mood. Furthermore, studies have shown that our gut microbiota can influence our stress responses in several ways.
Neurotransmitters produced by the gut microbiota, such as serotonin, can calm the brain and reduce anxiety and stress. The gut microbiota can also produce short-chain fatty acids, which can modulate the immune system and have anti-inflammatory effects.
Strategies to promote the growth of beneficial microorganisms in the gut, such as consuming a diet rich in fibre and fermented foods among other things, may help support mental health. However, much more research is needed to fully understand the fascinating and complex relationship between the gut microbiota and mental health.
You can learn more about probiotics in our Learning Lab.