The Gut Brain Axis: How Gut Health Influences Mental Wellness

Updated: Mar 27


  • Your gut health (microbiome) has a significant impact on your mind.

  • Your microbiome influences your brain through the nervous and endocrine system.

  • Through smart choices we take control of our gut health and how the microbiome impacts how we think, feel, and live.

  • The microbiome can influence our food choices. Once we overturn an overpopulation of bad bacteria our negative cravings subside.

  • High fibre and fermented foods are essential for fostering a healthy gut

  • Excessive sugar, artificial and processed food will multiply bad bacteria that are harmful to our mind and body.

  • A healthy gut creates a healthy mind, a healthy body, and a high quality life.


You are what you eat.

No, literally.

Your thoughts, feelings, and behaviour are largely determined by the quality of food you consume. Science is beginning to demonstrate that the relationship between our gut health and our mental state is more direct and impactful than we realise.

A new branch of science known as psycho-biotics is demonstrating how we can use what we put in our body to optimise the chemistry of our brain and our body. As we begin to understand the relationship between the microbiome in our stomach and the rest of our biology, we unlock the power to ensure our dietary choices support the creation of an unstoppable mind and body.


The gut is our “second brain”.

Our gut and our brain are tightly linked through the nervous system. Our brain is in constant two-way communication with our digestive track. Messages travel from the gut to the brain via the vagus nerve. This nerve runs from the bottom of the brain stem and through the body, connecting your mind with vital organs and large areas of the digestive track. The vagus nerve is very important. It is largely responsible for our mind-body connection and shows us that the mind does not operate soley in the skull. The mind and our subjective experience are shaped by the state of the systems below our neck. The nervous system collects data about the state of our physiology and relays crucial information to the brain about how things are going. There are approximately 500 million neurons in your gut that are directly connected to your brain. This is significant when you consider that the brain of small mammals such as cats and dogs ranges between 250-500 neurons (1). That’s another brain down there. Your gut health directly impacts the messages these neurons are sending to our brain and body. Our gut health is controlled by what we choose to put in our mouths. Thus, we are responsible for controlling the quality of communication travelling from our digestive system through to our brain and body.

So how does this all work?

When talking about gut health, we are talking about the state of the gut microbiome. This massive colony of microbes is responsible for producing many chemicals that flow through us and influence our every aspect of our daily experience. The various strains of bacteria produce a significant proportion of our neurotransmitters, hormones, and important fatty acids.

How do these bacteria shape the state of our mind and body?

1. Neurotransmitters

Serotonin- your microbiome is responsible for the synthesis of 90% of serotonin in the body (2). The chemical has marvellous effects on our brain. Serotonin plays a role in; producing a stable and elevated mood, regulating sleep and sexual function, and sustaining cognition. Studies are also now linking serotonin function to improved memory, neuroplasticity, and learning speed (3).

GABA- your gut microbes also produce a significant amount of Gamma-Aminobutyric Acid (GABA). GABA helps to regulate feelings of stress, fear, and anxiety (4); this give our a sense of calm and clarity in daily life.

No wonder science shows such a strong connection between gut health and mental health disorders. If you're seeking optimal experience and performance you cannot ignore your supply of GABA and serotonin.

2. Hormones

The gut plays a central role in the endocrine system. The microbiome produces many key hormones and also communicates with glands in the body to regulate how much of a particular hormone should be released (5).

Estrogen- the gut has an entire class of microbes called the ‘estrobolome’ that synthesise estrogen. Estrogen balance plays an important role in optimising mood in both men and women. Estrogen impacts the serotonergic, dopaminergic and noradrenergic systems (7). These systems create a feeling of subjective wellbeing by balancing feel-good hormones and levels of stress/adrenalin in the body.

Thyroid- a low diversity of gut bacteria is associated with abnormal levels of thyroid stimulating hormone (TSH). Too little of the hormone causes weight gain and memory decline, and too much can lead to irritability and anxiety (6). This can impact anyone.

3. Fatty Acids

SCFA: your gut microbes are involved in the production of short chain fatty acids (SCFA)’s. Science links SCFA production with the prevention of cognitive decline. SCFA's play a key role in neural regeneration and neutral plasticity (8). This keeps your brain young and open to learning, aswell as reducing levels of inflammation.


If the microbes in our stomach are producing the key ingredients for our mood, cognition, and health, should we not ensure we cultivate the right mix of bacteria?

The recipe for optimal neurochemistry comes down to influencing the demographic of our microbiome. This isn’t as difficult as it sounds. If we take control of our diet, we can essentially starve the bad bacteria, feed the good bacteria, and directly influence the Gut-Brain axis.

The two main elements we need to focus on are pre-biotics and pro-biotics. Pro-biotics are useful strains of bacteria, and pre-biotics are the food these useful bacteria need to thrive. It is the interaction between pre-biotics and pro-biotics that produce the feel-good magic.

The best diet for a helahty microbiome can easily be summarised in a gut right food pyramid.

If you work from the bottom up you will foster a flourishing and diverse community of gut bacteria.

At ALIVE our favourite interventions to building a friendly gut are to:

- Focus on hydration

- Give apple cider vinegar a try

- Eat natural yoghurt and a high fibre cereal in the morning

- Target healthy fats, such a avocado and fresh olive oil

- Consume fibre rich vegetables, look for dark colours (Pre-Biotics)

- Include polyphenols in your diet, such as dark chocolate (the higher cocoa content, the better), blueberries, green tea, and RED WINE!

- Try eating a variety of foods for a healthy mix of bacteria

To keep a healthy balance in your micobiome also avoid the following foods. This will starve harmful bacteria and minimise the toxic response the gut can have to some food:

- Those with excessive additives and preservatives

- Diet drinks with artificial flavours (e.g aspartame and sucralose)

- High sugar foods (harmful bacteria love and crave sweets)

- Avoid excessive alcohol consumption

Also note these dietary interventions are supported by other aspects of living a healthy lifestyle; getting enough sleep and reducing stress really helps our microbiome find balance naturally.


At ALIVE we love to explore the positive compounding effects that good habbits have.

This concept is no different. The food choices we make in the present have a huge impact on our future eating habits as well. Food cravings are an interesting and complex phenomenon. We may not be aware of it but we are not the only party involved in deciding what we eat. The bacteria in our gut have their own cravings too! Bad bacteria crave artificial, processed, and sugary food. Our good bacteria desire healthy, high fibre, pre-botic goodness. The competition for resources between various strains of bacteria in our microbiome is intense. Unfortunately, bad bacteria have winning strategies to convince us to help them get what they need.

Overgrown bad bacteria:

- Cause the body to produce a greater number of sweet receptors in the stomach and enhance craving

- Produce toxins that travel to the brain and create a feeling of low mood, energy, or ill health. These feelings can only be stopped when the bacteria receive their hit of unhealthy substances. This makes our cravings cyclical.

-Stop the production of GABA; this is associated with the desire for unhealthy food

-Halt the production of good fatty acids that are essential for creating the feeling of satisfaction after food and reducing unnecessary eating

The good news for us is that if we fight these cravings we can starve bad bacteria out and completely reset our microbiome in just 4 days (9).

Our healthy and balanced microbiome will now send signals to the brain that influence our food choices in a positive way.

When we understand that everything we put into our body in the present is going to make it easier or harder for us to make appropriate food choices in the future, we can break the cycle of dependence on unhealthy food. We begin to see that these bad cravings aren’t even our own!


A big part of ALIVE is to explore the relationship between the spheres of MIND, WELL and WISE. We want to know how these feilds interplay and work together.

Gut health is a prime demonstration of these links.


The relationship between our psychology and physiology is perfectly demonstrated through the gut-brain axis. Microbiome issues are strongly associated with depression, anxiety, and other serious mental disorders. The effect of a thriving gut clearly supports a positive internal state.


The effect on our philosophy is more subtle but cannot be understated. When we decide to follow a specific philosophy, we conclude that a particular way of behaving is important to us and to those we interact with. However, we all know that deciding to do something versus actually doing it is a different story. A large proportion of our intentions can be left unfulfilled due to a lack of energy and motivation. However, we are not always at fault. Poor gut health can deprive us of the chemical fuel we need to make our philosophies a reality. When the gut is on our side our brain chemistry is optimised and our reserves of mental discipline are much higher. Our resilience increases and we find it easy to commit to the goals we set for ourselves.