Did you know that the communication system between your gut and brain is called the gut-brain axis? Yes, these two organs are connected both physically and biochemically in a number of different ways.
The vagus nerve is one of the biggest nerves connecting your gut and brain. It sends signals in both directions. One study in humans found that people with irritable bowel syndrome (IBS) or Crohn’s disease had reduced vagal tone, indicating a reduced function of the vagus nerve.
Your gut and brain are also connected through chemicals called neurotransmitters, which are produced in the brain to control feelings and emotions. Interestingly, many of these neurotransmitters are also produced by your gut cells and the trillions of microbes living there. For example, a large proportion of serotonin (the hormone regulating our mood) is produced in the gut.
Your gut microbes also produce a neurotransmitter called gamma-aminobutyric acid (GABA), which helps control feelings of fear and anxiety.
Moreover, gut microbes affect inflammation. This is because our gut-brain axis is also connected through the immune system, controlling what is passed into the body and what is excreted.
If your immune system is switched on for too long, it can lead to inflammation, which is associated with a number of brain disorders like depression and Alzheimer’s disease.
Another important aspect to consider is that gut bacteria also affect brain health, so changing the composition of gut bacteria may improve your brain health.
Let’s make some clarity.
You may have heard of prebiotics and probiotics, but there is some confusion around the meaning of those.
Probiotics are live bacteria that impart health benefits if eaten. However, not all probiotics are the same. Some probiotics have been shown to improve symptoms of stress, anxiety and depression.
They can, for example, ease the symptoms of irritable bowel syndrome and mild-to-moderate anxiety or depression.
Prebiotics, which are typically fibres that are fermented by your gut bacteria, may also affect brain health, reducing the amount of cortisol, the stress hormone present in our body.