As humans, we place significant value on the communities we belong to. But do we give enough thought to the vast microbial communities we host inside our bodies? The microbiome is a bustling community of trillions of microorganisms of different species, predominantly bacteria but also archaea, fungi, viruses and parasites.
Did you know that the number of bacterial genes within your body vastly outnumbers your own? The trillions of bacteria that live in our bodies contain more novel genes than there are stars in the observable universe. Posing the question – are we more bacteria than human?
The largest and most important community of microbes live in the gut, but we have several microbiomes, most notably the oral, skin and (for women) vaginal microbiomes. Our interactions with our gut microbiome have a powerful impact on many areas of health – digestion, immunity, mood and cognition to name but a few. As we learn more and more about the microbiome, awareness of the need to nurture this community within is growing too.
What does a healthy gut microbiome look like? Our individual microbiomes are unique and distinct. From one person to the next, we only share roughly 20 per cent of the bacterial species in our gut. Meaning there is no ideal ‘blueprint’ to aim for. Simply put, we need a diverse range of beneficial strains to be present; these strains convey positive effects on our health and work to keep potentially trouble-making strains in check.
When it comes to nurturing our microbiome, we know that eating a diverse range of plant foods is important to nourish our gut bacteria. This is because they contain prebiotic fibre – a food source for the bacteria we want to encourage in our guts. Gut microbiota ferment prebiotic fibre, producing beneficial by-products – like short-chain fatty acids – which support the health of our gut lining and can help keep inflammation in check.
As well as feeding your microbiome, introducing fermented foods – which contain live bacteria – is a great way to support gut health. Foods like sauerkraut, kimchi and kefir contain a distinct population of microorganisms, which have a positive impact on our gut microbiome, either by colonising the gut or temporarily taking up space and allowing resident beneficial bacteria to thrive.
Microbial communities are also responsive to our interactions with other humans. Fascinatingly, studies have found that long-term intimate relationships impact our gut microbiome, with couples having more similar microbiomes than strangers. It’s also been shown that people with larger social networks tend to have a more diverse microbiome.
And it appears that our gut bacteria can influence our behaviour in turn. Recent investigations indicate that these microbes impact cognitive function and behaviour patterns, such as social interaction and stress management. Anxiety and stress have also been linked to reduced diversity, suggesting that interventions to improve gut health offer promising potential in the field of mood disorders.
Katerina Johnson, a researcher at Oxford University, has found that abundances of specific bacterial species are significantly predicted by personality traits. She reflects that: “Our diets are typically deficient in fibre, we inhabit over sanitised environments and are dependent on antibiotic treatments. All these factors can influence the gut microbiome and so may be affecting our behaviour and psychological well-being in currently unknown ways.”
We’ve long been aware of the powerful connection with our guts – with popular terms like ‘gut feeling’ and ‘gut instinct’. It’s fascinating that science is now exploring the mechanisms behind this. Hopefully this growing awareness will lead to us living in greater harmony with our microbial communities and reaping the health benefits this brings.
This piece was initially published in the spring-summer edition of Wicked Leeks magazine. You can read the full magazine online for free.