Serotonin, often known as the happiness hormone, is produced in the brain and helps stabilize your mood and feelings of well-being. However, did you know that 95% of our body’s serotonin is found within the gut? (I know, who thought of this motivation for looking closer at your gut health?)
While stress and anxiety may lead to digestive symptoms like indigestion, stomach cramps, diarrhea, loss of appetite, emotional eating, or nausea, many studies have shown that improving gut health can also support better mental health.
Your colon is home to trillions of bacterial cells which make up a unique ecosystem called the gut microbiome. As well as allowing nutrients to enter the body and keeping opportunistic pathogens locked out, their activities also influence your brain.
When the body is exposed to stress, it goes through a series of changes so that all energy and major resources are directed to the muscles and brain. Stress also causes the body to release cortisol, and all these factors can affect the gut microbiome. Equally, if your gut microbiome is imbalanced (dysbiosis), then your overall mood can be affected. That’s because the activity of your gut bacteria affects stress and anxiety — a balanced microbiome can improve your stress resilience, but an imbalanced one can affect your mental health. Here’s how probiotics, depression, gut bacteria and mental health are linked.
Your gut and brain are connected by the vagus nerve
This is a major component of the autonomic nervous system which enables you to breathe, digest food, and swallow automatically. This nerve is able to send messages to your brain for your colon, and vice versa. The connection between the two organs means that the gut-brain axis is becoming a vital player in mental health, illnesses that affect the brain, and even irritable bowel syndrome (IBS). It explains why stress can take a toll on your digestion, but also why digestive problems can make you unhappy.
To support your health, your gut microbiome needs to be diverse, and diversity helps keep it balanced. However, if it is not balanced opportunistic microbes can take advantage and proliferate, resulting in inflammation. That’s because your body doesn’t want opportunistic bacteria, so your immune system is alerted, resulting in inflammation. Interestingly, inflammation can contribute to depression, and depression can cause inflammation. But a diverse microbiome can prevent inflammation.
So, controlling inflammation can help to improve both mood and anxiety levels. Diet is one way to increase the abundance of diverse microbes and reduce inflammation. Beneficial gut bacteria thrive on a natural, plant-based diet because fiber is an important source of energy for them.
Butyrate effect
Butyrate is a short-chain fatty acid produced by good gut bacteria when you eat plants (fruit, veg, seeds, nuts, whole grains, legumes). It doesn’t just keep your gut happy, your brain benefits too. Butyrate is the main source of fuel for the cells of your gut lining, so it helps keep this barrier strong and intact. It also helps prevent inflammation, which can be bad for your mood. A new study even shows that butyrate might help you grow new brain cells.
The great news is you can actively contribute to the butyrate production in your gut through your diet. One way is by eating prebiotics: foods which directly provide sustenance to your gut bacteria, like fruit, vegetables, whole grains, and pulses. These contain fibre which is transformed into SCFAs like butyrate.
What about probiotics vs prebiotics? Which ones are helpful?
Probiotic bacteria provide many health benefits, including for the brain. They naturally reside in the gut but are also found in supplements and fermented foods, like yoghurt and kefir. Bifidobacterium, Lactobacillus, and Lactococcus species are all examples of probiotics because they support your whole-body and improve mental health too.
So, you’ve upped your probiotic intake, but to reap all their health benefits, you need to keep them nourished. Just like you, your gut bacteria need food to keep them sustained, energised, and thriving. That’s where prebiotics come in.
Prebiotics are substances found in plant-based foods which maintain beneficial gut bacteria. Prebiotic fibres and resistant starches all nourish gut bacteria which in turn transform them into good things like SCFAs and vitamins.
| Prebiotic fibres | Resistant starches | Polyphenols |
| Garlic | Legumes | Onion |
| Onions | Seeds | Apples |
| Berries | Grains | Tea |
| Jerusalem artichokes | Green bananas | Cocoa |
| Mushrooms | Cooked and cooled potatoes | Red wine |
| Rye | Plantain | Red fruit |
| Barley | Corn | Soybeans |
Research has also shown that consuming prebiotics is also associated with a reduction in anxiety-related behaviour. So it’s important to never underestimate the role of your diet in improving mental wellbeing.
So, you know that your gut microbes are pretty cool and transform food into short-chain fatty acids? Well, these SCFAs communicate with cells which produce serotonin, a neurotransmitter (and a hormone) that regulates your mood, as well as levels of anxiety and happiness. Basically, your gut microbes can help your body produce more serotonin.
Equally, another neurotransmitter, Gamma-Aminobutyric Acid (GABA), regulates and improves mood because it helps to calm the nervous system and switch off stress reactions. Amazingly, some probiotic gut bacteria can even produce GABA themselves for your body.
Summary
Fundamentally, your diet can help your bacteria protect your mental wellbeing because eating the right foods feeds happy bacteria. And when you have lots of different healthy bacteria, your microbiome is more diverse and produces substances which increase mood-lifting chemicals, like serotonin and GABA.
If you’d like to learn more about the foods that help you keep your energy at high vibration rate please read another article on healthy eating here: Top Foods for Raising Your Vibration Today
