What’s the link between fermented foods and the gut-brain axis?
The effect the gut has over the brain has become one of the hottest topics in nutrition in recent years. Known to neuroscience as the gut-brain axis, we explore this wonder in this week’s article in the context of its link to fermented foods.
For me, personally, and many others, this is a issue that is very close to home. I have known many people in my life who I have loved dearly, who have struggled with mental health.
The gut is also known as our body’s “second brain”. It doesn’t “think” in the same way as our main brain. But it communicates with our brain and therefore does influence the decisions we make and the moods we feel. This is just one of the ways our gut health plays an important role in our physical and mental health.
So, what is the gut-brain axis and how can eating foods that have been fermented, such as kimchi, sauerkraut and yoghurt, affect our mental health?
The gut-brain axis — a quick tour
The brain is linked to the gut in two ways. Through the nerves in our nervous system and the fascinatingly-sounding vagus nerve. Another name for the vagus is “wandering”. And that’s exactly what it does, wander from the gut to the brain. Signals are sent in both directions: from the gut to the brain and vice versa. This may account for the familiar “butterflies in the stomach” feeling when we’re feeling nervous.
This channelling of information from our gut to our brain is governed by our microbiome — the bacteria that forms a major part of the gut system. It has developed and populated our gut since our birth and forms one of our most important symbiotic relationships. The bacteria in our gut governs so much of our health and wellbeing.
Several scientific studies now show what ancient wisdom has suggested for thousands of years: there is a link between the gut and the brain. By extension, what we eat will affect our mood.
How are fermented foods linked to mental health?
As the gut is linked to the brain, it follows that what we eat will affect mental health. A 2019 review of several studies by researchers at the Shanghai Mental Health Center at Shanghai Jiao Tong University School of Medicine found a number of links.
The review, published in the magazine General Psychiatry, found that evidence exists of a link between probiotics and mental health, specifically anxiety. Known as “probiotics” because they are pro-life, they are found in immense quantities in fermented foods such as sauerkraut, kefir, yoghurt and kimchi.
"We find that more than half of the studies included showed it was positive to treat anxiety symptoms by regulation of intestinal microbiota,” the researchers concluded. They also advised that this was an observational review of existing studies. They said that, although the design and methodology of the studies differed, the overall quality of the studies was high.
Another narrative review published in Nutritional Neuroscience journal “explores the theoretical potential of the functional components present in fermented foods to alter gut physiology and to impact the biological mechanisms thought to underpin depression and anxiety.” It analyses eight Australian studies to further the conversation on the influence of fermented foods and mental health.
So how can we support our mental health most effectively?
But how does this translate to real life?
With lifestyle and exercise, the role of nutrition is foremost in managing the balance of our gut microbiome — all of the bacteria contained in our gut — in favour of the “good bugs”.
Excellent nutrition involves eating a high fibre diet. This will “feed” the good bacteria so they proliferate. It also means eating a diet high in probiotic-rich food — and this is where fermented foods come in.
Foods such as sauerkraut, kimchi, kefir, kombucha and yoghurt have all been fermented in anaerobic conditions. That is without oxygen. This allows certain bacteria such as lactobacillus to predominate and break down the food. The great news for us is that these bacteria are also good for our mental and physical health.
The evidence for a link between consuming foods that have been fermented and excellent mental health is growing. To benefit our health, aim at increasing foods that have been fermented. However, it is important to check if they contain live bacteria. Food that has been pasteurised will kill all good bacteria. To make sure either check the label or make them yourself. Check out all our recipes and resouces in the blog, on facebook, and our Online Masterclass and Saurkraut ebook. to learn how to do this.
While studies now show a clear link between fermented foods and gut health, this should not be used as a replacement for medications. Always consult with your health professional before changing your diet and seek their help first if you are suffering from mental health problems.
Interested in finding out more about fermenting foods? Join our online fermenting masterclass to learn how you can become a great fermenter in your own home. Use the code HEALTHY at the check-out, for an EPIC discount.
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Yours in continued expansion into vibrant health, Sammi xxx