According to recent studies, it seems there is more to this “gut feeling” than a simple sensation. In fact, scientists are discovering that this connection goes both ways – that gut bacteria and brain health are inextricably linked.
This link between your gut bacteria and brain health is called the ‘gut-brain axis’ and it exists as a pathway, connecting the two organs both physically and biochemically.
How does the gut-brain axis work?
The vagus nerve, one of the biggest in the nervous system, plays an important role in connecting your gut and brain – sending signals both ways. Some studies have shown that when these signals are inhibited (such as through stress), it can cause gastrointestinal problems.
Gut microbes are another aspect that connects the gut and the brain. These microbes produce types of short-chain fatty acids (SCFA) when digesting fibre. Several studies have shown that SFCA can affect brain function in varying ways.
A 2016 study, published in PubMed found that consuming a certain type of SCFA reduced the activity in the brain related to reward from high-energy food, and therefore reducing food intake through reward-based eating behaviour.
What happens when your gut bacteria changes?
Since there are billions of types of different gut bacteria, no two guts are the same. Many scientists have looked at what happens to the brain when your gut bacteria changes.
Looking at different types of probiotics, 2016 study found that certain types were shown to improve symptoms of stress, anxiety and depression.
Another study in 2015 discovered that taking a certain prebiotic significantly reduced the amount of cortisol, the stress hormone found in the body.
What are the best foods for your gut-brain axis?
When it comes to gut bacteria and brain health, there are several foods with known benefits:
- Fermented: Kefir, yoghurt and kimchi all contain healthy lactic acid bacteria which has shown to boost brain activity.
- Omega-3 fats: Oily fish are a great source of omega-3 which are found in the brain.
- Fibre-rich: nuts, seeds, fruits and vegetables all contain healthy prebiotic fibres that are beneficial for gut bacteria and brain health.
