Could your gut health be impacting your mood?

Each month, Flourish Events aims to empower women by connecting them with experts and health professionals in the industry and bringing them credible advice and tips for living a healthy, happy & sustainable lifestyle. In our fourth blog post, Kristy Coleman, Registered Nutritional Therapist & gut health specialist uses evidence-based research to explore gut-brain connection and how your gut health may be impacting your mood.

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Even though the gut and gut microbiome have been researched for decades, we are only now starting to see more promising evidence on the gut brain connection and its ability to influence mood. In 2018 alone over 10,280 research papers 1 were published on the microbiome! Gut health is now a staple feature in the health and wellbeing sector, which has seen a rise in fermented foods, drinks, supplements and test kits claiming to support gut health. But what does gut health have to do with mental health?

What is the gut?

It is first important to understand what is meant by the term ‘gut’. Your gut runs from your mouth to anus and is supported by your stomach, liver, gallbladder and pancreas. A few facts about the gut:

  • aids the digestion of food and the absorption of nutrients

  • houses approximately 70% of your immune system

  • includes cells lining your gut, which are responsible for producing approximately 90% of your body’s serotonin, which is a neurotransmitter (a chemical signal for the brain)

  • home to trillions of microbes called your microbiome.

  • communicates back and forth to your brain through the vagus nerve

What is the gut microbiome?

Now we know what the gut is, it useful to know what your gut microbiome is. The microbiome is a term used to describe the trillions of microbes (including bacteria, yeast, fungi and parasites) living within your gut, with over 10,000 species identified. Your own microbiome is more unique than your DNA. Even identical twins will have different microbiomes. Your microbiome plays an important role in overall health, including mental health and wellbeing and may even protect you from some diseases and disorders.

Think of your microbiome as an English country garden, you want a variety of different plants (beneficial microbes) and not too many weeds (less beneficial microbes) for optimal microbiome health. We need our microbiome to be diverse and balanced to work well. If our microbiome becomes imbalanced, for example, due decreased diversity of beneficial microbes, this can affect our overall health and wellbeing, in particular, our mental health.


The brain and gut are connected in more ways than one and what is going on in your gut, can influence your mental health.

1. Physical connection

Ever feel sick to your stomach when you are nervous or feeling anxious, fearful or stressed? This is the gut/brain connection in action. Your brain and gut are physically bidirectionally connected and communicate through the vagus nerve, which runs from your brain all the way through to your gut – this nerve controls mood, immune response, digestion and even your heart rate.

2. Microbiome

Your gut microbiome has the ability to alter your mood and has been linked to anxiety and depressive behaviours and can alter how you manage stressful situations. Your microbiome may modify the activity of the vagus nerve by altering how the cells in your gut work.

Your microbiome can influence the activity of your neurotransmitters, such as serotonin, dopamine and GABA, which send chemical messages to your brain to control how you feel. If you don’t produce enough or too much of a neurotransmitter, this can affect your mental health. For example, low serotonin levels have been linked with depression. Your microbiome has the power to produce small amounts of serotonin themselves and also has the ability to influence your nervous system and change how neurotransmitters are produced and utilised and also alter how available tryptophan is (a building block for serotonin). In addition, your microbiome can impair your immune system, which also influences neurotransmitter activity.

Research released earlier this year has shown that people with depression are less to have certain gut bacteria. This is not to say bacteria causes depression, but lack of certain strains can contribute to its onset.

Take Home

The gut/brain connection is incredibly complex and despite researching it for decades, science still has a long way to go until we have a clearer picture about the gut and microbiome and their collective role in mental health and how best to support it. A lot of research is on animals, which isn’t always reflective of what happens in humans so it will be interesting to see what happens as the research around this topic expands.

The good thing is your microbiome is capable of being altered through dietary and lifestyle factors. The more diverse and colourful (with a focus on plant-based foods) your diet is, the happier and more diverse your microbiome will be.