Health and fitness

What exactly is the gut-brain connection (and how does it impact mental wellbeing)?

By the team of mental health professionals at Koa Health

Have you ever heard your gut referred to as your second brain? The trillions of tiny microorganisms that live in our stomachs directly affect our mood, stress levels, anxiety and even how we think.

Interestingly enough, these microorganisms weigh roughly the same as the brains they’re so connected to. Keep reading to find out more about the relationship between the two (often referred to as the gut-brain connection).

How grey matter and your gut relate

Since before science could demonstrate the link between our digestive systems and brains, people have talked about feelings by making reference to their stomachs. Two common examples include a ‘gut instinct’, aka, a hunch or intuition, and ‘butterflies in their stomachs’ an expression we use to talk about feeling nervous or excited.

These expressions have taken on new significance and with the help of science and research, we’ve begun to understand the strong ties between these two regions of the body.

For starters, beyond digestion, the health of our gut directly affects our brain and as a result of this, our overall mental wellbeing. By the same token, the thoughts and feelings our brains produce directly affect our stomachs.

This is a two-way relationship known as the "gut-brain axis".

While we’re aware of how our brain can affect our stomachs—for instance, when it gurgles in anticipation of the delicious food on the table—our emotions also clearly affect our gut. You might notice when you’re sad, anxious or upset, you feel knots or pain in your stomach and can even have digestive problems that have you feeling nauseated (or running for the bathroom).

But you may be more surprised to learn that upsets in your digestive system can affect your emotions and mental wellbeing, as well.

Trillions of microorganisms such as bacteria, fungi…etc (aka what scientists call the gut microbiome) live in your gut. And these small-but-mighty beings can make a big difference in how you feel.

A team of scientists in Belgium has demonstrated about 50 different ways that these tiny organisms produce chemicals affecting our brains and moods. One such example is serotonin. 90% of this mood-regulating hormone, sometimes called the ‘happy’ chemical, is actually formed in your gut.

Your gut and brain talk to one another via the vagus nerve—the longest nerve in the body connecting your brain and your gut—bringing our brains, and our stomachs together more than you’d think.

This nerve tells the brain what’s going on in the gut, which in turn tells the gut what it should be doing in terms of satiety (feeling full) and digestion.

The "flight or fight" response that’s triggered by stress affects communication along the vagus nerve leading to changes in the gut. This can affect the microbiome balance and the absorption of chemicals into the bloodstream—these chemicals can affect the brain and, in particular, mood.


Can a healthier gut microbiome improve mental wellbeing?

Research is beginning to show that a good balance of bacteria and a calm gut actually contribute positively to mental health. A diverse microbiome may also aid in mental health as it strengthens the gut lining and protects the body from toxins.

Read on for two ways to support (and potentially improve) your gut microbiome (supported by science).

1. Probiotics

You’ve probably heard of probiotics, but did you know that they can contribute to our wellbeing and may make it easier for our bodies to handle stress?

While they already exist in our gut microbiome, we can also add them in by eating fermented foods like yoghurt, kefir, kimchi or kombucha—if picking up pasteurized versions at the store, make sure they say they contain "live probiotics" or "live cultures" before buying.

2. Prebiotics

Prebiotics are found in high-fiber foods like fruit, vegetables, nuts, and legumes. These foods have plant fibres our bodies can’t break down and digest that become food for the microorganisms in our gut, keeping them healthy and balanced.


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