Nine ways that your gut affects mental health

A balanced microbiome can improve your stress resilience, so it’s beneficial to know how probiotics depression, gut bacteria and mental health are linked. – Photos:

Our colon contains trillions of bacterial cells which make up a unique ecosystem known as the gut microbiome. Other than letting in nutrients into the body and locking out harmful pathogens, the activities of your gut bacteria influences your brain a lot more than you might realise.

Take being under stress as an example. The body undergoes a variety of changes when it is exposed to stress. A great deal of energy and major resources get redirected to the muscles and brain. One of the body’s main responses to stress is to release cortisol, and that plays a big role in affecting the balance of the gut microbiome.

Regardless of the reason why your gut microbiome is in a state of imbalance or dysbiosis, your overall mental health can be affected. A balanced microbiome can improve your stress resilience, so it’s beneficial to know how probiotics depression, gut bacteria and mental health are linked.

1. Better diversity in your microbiome composition is good for mental health

There is a link between gut bacteria and depression. Everyone has a unique gut microbiome and it’s becoming clear that the more diversity in healthy bacteria, the better it will be for your body and mental health.

Because the composition of the gut microbiome can reveal a lot about what is going on in other parts of your insides, it’s a good idea to get a personal microbiome health status with a test that you can get from a doctor. The test will show how diverse your microbiome is, how well it produces butyrate, and even what foods you should eat to support a healthy and happy microbial ecosystem.

2. Low butyrate is bad for the brain

Butyrate is a short-chain fatty acid that is essential to the body and is produced by good gut bacteria. You can get it by eating vegetables, fruit, nuts, seeds, whole grains, legumes). Butyrate is the main source of fuel for your gut lining cells, and helps keep the lining strong.

Butyrate doesn’t just keep your gut happy, your brain benefits too. New research is indicating that butyrate might help you grow new brain cells.It also helps prevent inflammation and improves mood. If your gut is in a state of dysbiosis, your gut will reduce its production of important nutrients and butyrate levels will be affected.

One way to help butyrate production in your body is by eating prebiotics. These can be found in food like fruit, vegetables, and whole grains. These foods are high in fibre and can be transformed into short-chain fatty acids like butyrate.

3. The vagus nerve communicates with the brain and aids digestion

Your gut and brain are connected by the vagus nerve, a major component of the autonomic nervous system. It enables you to automatically digest food, breathe, and swallow automatically.

Vagus nerve aids digestion in the following ways:

  • Motility — helps food to move through the digestive tract
  • Digestion — stimulates the release of digestive enzymes
  • Appetite — communicates satiety to the brain

The connection between the gut and brain, known as the gut-brain axis, plays a vital role in mental healthand even irritable bowel syndrome (IBS). This may explain why digestive problems make you anxious and unhappy.

4. Gut bacteria needs to talk to your brain

Gut bacteria breaks down food and transforms it into metabolites like short-chain fatty acids. The vagus nerve detects the information and sends messages to the brain, allowing the regulation of digestive processes.

But when the vagus nerve is impaired by stress, it fights inflammation less effectively. This is naturally bad for the balance of your gut bacteria, hence why your vagus nerve is so important.

5. A healthy gut encourages more happy hormones

Gut microbes can transform food into short-chain fatty acids, which then communicate with cells to produce serotonin, a neurotransmitter and hormone that regulates your mood, including anxiety and happiness.

A healthy gut also encourages the production of another neurotransmitter, Gamma-Aminobutyric Acid (GABA), which regulates and improves mood. Some probiotic gut bacteria can even produce GABA themselves, helping to calm the nervous system and switch off stress reactions.

Eating the right foods with lots of variety helps to feed happy bacteria. When your gut has plenty of healthy bacteria, your microbiome is more diverse and produces substances which increase mood-lifting chemicals, like serotonin and GABA.

A healthy gut encourages more happy hormones while an imbalanced gut can contribute to depression.A healthy gut encourages more happy hormones while an imbalanced gut can contribute to depression.

6. Gut bacteria influences depression and inflammation

Diversity in your gut microbiome helps keep it balanced. But if you are in a state of dysbiosis, opportunistic (and even harmful) microbes will seize the chance to proliferate. Your body responds by alerting the immune system, which prevents the opportunistic bacteria from taking over by triggering inflammation.

problem is that inflammation can contribute to depression. So, controlling inflammation can help to improve both mood and anxiety levels. Adding variety to your diet is one way to increase the abundance of diverse microbes and reduce the risk of dysbiosis.

7. Probiotics and depression

To increase diversity in your gut bacteria, try adding probiotic food or supplements to your diet. While they reside in the gut naturally, they are also found in supplements and fermented foods, like kimchi, yoghurt, and kefir.

Bifidobacterium, Lactobacillus, and Lactococcus species are examples of common probiotics that support your gut health, as well as brain health.In the field of psychobiotics, the effects of probiotics and mental health are researched and studied. New early findings indicate that certain lactobacillus species improves stress resilience and anxiety. Some studies even show that probiotics can help reduce the symptoms of depression.

Probiotics food concept such as kimchi, beet sauerkraut, sauerkraut, kefir and pickled cucumbers can improve gut health.Probiotics food concept such as kimchi, beet sauerkraut, sauerkraut, kefir and pickled cucumbers can improve gut health.

8. Eat prebiotics to nourish probiotic bacteria

Probiotics aren’t the only type of food or supplement you can take to increase the healthy bacteria in your gut. To optimise their benefits, you’ll want to provide nourishment for your gut bacteria to keep them energised and thriving.

To do that, you’ll need to take prebiotics.These are substances found in plant-based foods which help to support healthy gut bacteria, transforming them into short chain fatty acids and vitamins.

Here’s a partial list of prebiotic foods you can easily add to your diet:

Prebiotic fibres

  • Mushrooms
  • Onions
  • Berries
  • Garlic
  • Barley
  • Rye
  • Corn

Resistant starches

  • Grains
  • Plantains
  • Legumes
  • Cooked and cooled potatoes
  • Green bananas
  • Seeds


  • Soybeans
  • Apples
  • Red wine
  • Cocoa
  • Tea
  • Onions

Consuming prebiotic foods is also linked to a reduction in anxiety-related behaviour. In other words, diet is critical to improving mental wellbeing. If you know the composition of your gut bacteria, you’ll be able to get personalised food recommendations to improve diversity. The easiest way to know is by getting a gut microbiome test.

9. Be happier by balancing your gut bacteria

The connection between the gut and the brain is an important example of how changes in one part of the body can influence another. As our knowledge about the gut microbiome expands, it’s become clearer that the link between the two affects mental health. Hence, an imbalanced gut microbiome creates a state of dysbiosis, which is the main culprit for many diseases including mental health issues.

Current research has been promising, indicating that changes in the gut microbiome and inflammation in the gut can affect the brain and cause symptoms that look like Parkinson's disease, autism, anxiety and depression and taking probiotics and prebiotics can have positive effects on these symptoms and stress resilience.

Datuk Dr Nor Ashikin Mokhtar is a consultant obstetrician and gynaecologist, and a functional medicine practitioner. For further information, email The information provided is for educational and communication purposes only, and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.

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