By Sandra Mikhail, an internationally-known accredited practising dietitian & author of The Gut Chronicles
We’ve all had butterflies in our stomach or been told to trust our gut, so it’s no surprise that the gut is often dubbed the “second brain.” This intuitive connection between our gut and emotions is more than just a metaphor. As a dietitian specialising in gut health, I’ve witnessed firsthand how the foods we eat can impact our mental well-being. Here, we’ll explore the gut-brain axis, the role of gut microbiota in mental health, and practical tips to foster both gut and mental well-being.
The Gut-Brain Axis: A Two-Way Communication Network
The gut-brain axis is a sophisticated communication network linking the gastrointestinal tract to the brain, enabling them to continuously exchange information. This connection is anchored by the vagus nerve, which acts as a communication highway between the gut and brain. Neurotransmitters, chemicals produced by gut bacteria, travel along this nerve to influence mood and behaviour. Interestingly, this is a two-way street-your brain can send signals back to your gut, impacting its function.
Here are some key facts that emphasize why the gut is often called our “second brain”:
- The brain and the gut are the only two organs with their own nervous systems, with the gut’s system known as the “enteric nervous system.
- There are more neurotransmitters in your gut than in your brain.
- Around 50% of the body’s dopamine and 90% of its serotonin are produced in the gut.
These discoveries underline the significant role of our gut microbiome beyond digestion, influencing brain development, behaviour, and potentially contributing to mental illness. Emotions like stress and anxiety can directly impact gut health, leading to symptoms such as bloating and diarrhoea, by disrupting the gut-brain axis and harming gut microbiota.
Disclaimer: Gut-produced neurotransmitters like serotonin act differently from brain-derived ones. While brain-derived serotonin primarily affects mood and emotions, gut-derived serotonin regulates digestion and influences mental health indirectly through the gut-brain axis.
The Microbial Influence
Our gut hosts trillions of microorganisms, collectively known as the gut microbiota. These microbes actively participate in bodily functions, including mood regulation and behaviour. An imbalance in gut microbiota, known as dysbiosis, has been linked to mental health disorders like anxiety and depression. Emerging studies suggest that certain gut bacteria strains can influence neurotransmitter production, impacting brain function and mental health. We also have prebiotics and they are non-digestible fibres that support beneficial gut bacteria and promote a healthy gut environment. These fibres produce short-chain fatty acids like butyrate, which are being studied for their impact on mental health.
My Top Tips for Supporting Gut Health and Mental Well-Being
Consume More Fermented Foods: Fermented foods like yogurt, kefir, and kimchi are rich in probiotics, supporting a diverse gut microbiome, which is crucial for mental health.
Diversify Your Diet: Aim to include 30 different plant ingredients weekly, such as fruits, vegetables, and whole grains, to nourish gut bacteria and promote a resilient ecosystem, linked to lower anxiety and depression levels.
Increase Butyrate-Producing Foods: Foods like barley, chickpeas and oats promote butyrate production – a short-chain fatty acid that reduces inflammation and supports gut health, which in turn influences the gut-brain axis.
Practice Diaphragmatic Breathing: Regular diaphragmatic breathing reduces stress hormones and promotes gut health by supporting the body’s relaxation response.
About the expert
Sandra Mikhail, the gut health dietitian making poo talk “salon chic”, is an internationally-known accredited practising dietitian, author of The Gut Chronicles and the founder and director of Nutrition A-Z (nutrition-az.com)
