The gut is a complex system that starts in the mouth and ends in the rectum, passing through the oesophagus, stomach, intestines and colon along the way. Through its course, food and nutrients are digested and absorbed into the blood stream.

Until recently, we thought this was all the gut system did – it fed the body. But over the past twenty years there has been a revolution in how we understand the breadth of its function, realising that it plays a fundamental systemic role in health.

Intuitive expressions such as having ‘a gut feeling’ are being shown to have scientific credibility. The part played by our gastrointestinal microbiome – the rich world of bacteria and fungi that populates it – in the body’s chemical signalling and communication system is becoming ever more evident.

Health and wellbeing

Today we know that the ecology of the gut influences mood and gastrointestinal function. One reason attributed to this is the ability of a healthy gut microbiota to metabolise tryptophan, an amino acid derived from food proteins, especially rich in lentils, oats, beans, nuts and seeds. The more tryptophan we have available, the more serotonin – the so-called happy hormone – we are able to synthesise. Serotonin is a key neurotransmitter at both terminals of the brain-gut axis, a bidirectional communication system between the central nervous system and the gastrointestinal tract, and 95% of the body’s supply of serotonin is found in the gut.

Good gut bacteria, such as Bifidobacteria and Acidophilus, promote symbiotic interactions with the mycelium Candida Albicans. These mycelium yeasts are opportunistic pathogens, and if they are not kept in check by good bacteria they can morph into a harmful fungus known as Candida. When compromised, the immune system tries to fight Candida with a histamine reaction but as this yeast usually hides in the gut walls at the bottom of the microvilli, the histamine can’t locate it and prevent it from spreading. The result is a yeast infection known as candidiasis, which tips the gut’s ecosystem out of balance. This reaction is analogous to a lake that becomes eutrophic over time due to excess nutrient pollution.

When we are persistently stressed, our immune system can be weakened, leaving us more susceptible to candidiasis. Examples include patients with cancer and AIDS, hormonal changes such as puberty or pregnancy, or forced hormonal changes through birth control pills or steroids. In immune-compromised patients candidiasis can be life threatening. The main environmental causes of candidiasis are poor diet (low in nutrients and high in fat, toxins – including cigarettes and alcohol – and processed carbohydrates) and the use of antibiotics, which destroy gut bacteria. In relatively mild cases, an overpopulation of candida can manifest itself as thrush or tiredness.

Fermented foods respect the ecology of our gut

In biological terms, ‘to culture’ means to maintain tissue cells, bacteria and other parts of living things so conditions are suitable for growth. A healthy microbial community, with a balanced symbiotic culture has an indeterminate list of positive actions. It will buffer the effects of a genetic predisposition to obesity, detoxify heavy metals, promote gut motility, protect against food allergies, synthesise K and B vitamins and improve heart health.

Eating fermented foods could be one way to support the culture of our gut and reduce our chance of illness. Fermented foods are made from a live culture of symbiotic yeast and bacteria. There are many common food sources, such as yoghurt, kefir, sauerkraut and apple cider vinegar, sharing these probiotic (pro life) qualities.

In one study, albeit a small one with 25 women, UCLA researchers found that eating fermented milk (yoghurt) containing live bacteria, including lactobacillus and bifidobacterium, twice daily for four weeks had a positive impact on the subjects’ gut microbes and mood.

Listening to your gut means listening to your mood

We all go through high peaks and low troughs in our life, but if we do not become more aware of the impact our food and lifestyle choices have on our health and well-being, then our moods could get worse. When we are stressed for instance we produce cortisol, a hormone that depresses our immune system, raises our blood sugar levels, inflames cells and breaks down tryptophan. If we continue to do things that make us stressed and supress the warning signs with foods that give us a short-term boost, such as sugary chocolate or a cheap takeaway, it could result in long-term illness, such as high cholesterol, cancer or clinical depression.

It will take nothing short of a personal transformation to attend to our emotions in a world where speed and convenience reign supreme. Ridding ourselves of a quick-fix addiction and consciously choosing food that repopulates rather than depletes our internal ecosystem is not an easy change. However there are four principles influenced by Ayurveda, a holistic approach to medicine, which can help to start the process.

Re-think

Take time to cook and prepare healthy meals with foods that are fermented and contain tryptophan – though remember that tryptophan needs carbohydrates to activate serotonin release. Eat slowly to ruminate on other aspects of your life that you need to slow down, and give time to allow your stomach to fill up. Be mindful not mindless.

Re-group

Move away from desk eating and meals for one and towards sharing home-cooked meals among friends, family, colleagues or neighbours. Ayurvedics suggest we eat meals together but in silence as it forces us to focus on digesting our food.

Re-new

Eat seasonal, fresh and organic food that is good for the soil and good for the gut. Local food supports the local economy and reduces our dependence on industrial food production. Industrial food systems largely produce processed food, which is harmful to your gut microbiome. If it’s hard to find affordable healthy food where you live, speak with your local councillor or supermarket about what you need and what you don’t. If available, join a box scheme, Food Assembly or food co-op.

Re-act

Finally, take long walks and engage with contemplative exercise such as yoga. These are great ways to reduce stress and clear the mind.

The gut may be hidden from view but as the research shows it is a key factor in long-term health and happiness. As such, becoming aware of and listening to this part of our internal communication system could be a powerful way to take care of yourself and may even improve your ability to take on the world.

Photograph: Oregon Department of Agriculture

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