How do we get our gut flora?
We share our bodies with several hundred microbial species...
WE ARE SUPER-ORGANISMS
Current estimates suggest that we each possess roughly 38 trillion bacterial cells on our body’s surfaces. Compared to the 30 trillion human cells, this puts the ratio of microbes to your human body cells at a little greater than 1:1 – in favour of the microbes!
Imagine yourself as a fluffy swarm of bacteria on legs. A parallel universe living inside of our bodies. Freaked out yet?
Whilst most of these inhabitants are beneficial or harmless, a tiny number of them are unwanted and pathogenic. Important for the production of some nutrients and vitamins, drugs, modification of gut surfaces and training of the immune system (amongst other things), these organisms are in constant communication with our bodies through the superficial linings of their respective organs. Yet when the delicate microbiome is knocked out of balance – or gains entry to other areas of the body, poor health kicks in. (See references below 2-8)
So, how do we get this microbiome in the first place?
BIRTH + VAGINAL SEEDING
We are essentially totally sterile in our mother’s womb. Or so we thought. Though still contentious, recent studies are suggesting that gut colonization may begin before birth, in the womb.
Then, through the act of birth, the newborn is inoculated with microbes through passage down the vaginal canal before gathering microbes from its environment; the doctor’s gloved hands, our mother’s skin, the bedding and clothing. We know that microbes are then detected in an infant first poop.
Together, these pioneer species put into place the building blocks needed for a fully-functioning microbiome.
This process does not occur in caesarean section births wherein the infant evades passage through the birth canal so microbes from this region are not encountered, and microbes that survive the sterile cleansing of the maternal skin are met instead. Caesarean-born infants (who are significantly higher risk of allergic disease) typically begin life with a microbiome more similar to that of the maternal skin microbiome (than vaginally born infants) and differences in make-up between modes of delivery have persisted up to 7 years into life. To counteract these differences in microbial profile, a process known as vaginal seeding has emerged in which vaginal fluids that contain vaginal microbes are applied to a newborn child born by C-section in a process of artificial inoculation. This is done in order to replicate the colonisation that occurs as a result of vaginal birth. Whilst it has been shown in a small study that vaginal microbes can be partially restored to C-section delivered babies via this technique, concerns have been raised that the little evidence that exists to support this trend is insufficient to outweigh its risks – such as colonisation by pathogenic species. There remains much speculation, namely whether the process is effective at priming the immune system, whether it confers lasting colonisation and in which individuals the swab would be beneficial. The process is therefore not currently recommended. Instead, other contact is encouraged postnatally, which can encourage sharing of microbiota and early breast feeding.
THE FIRST FEW YEARS
It only takes between one and three years for a gut flora of an adult’s maturity to become established and this window of colonisation crafts the microbial landscape leading into adult life. Within this time, pivotal interactions and experiences will occur. These include the initial mode of birth, breast vs. formula feeding, antibiotic use and an increasing interaction of an infant and it's environment.
BREAST IS BEST FOR GUT HEALTH
Nature’s best, our good friend, breast milk has an important role to play. Rich in short chain fatty acids, special sugars, beneficial bifidobacteria and leukocytes; helping to craft this growing microbial community into something useful.
ENVIRONMENTAL FACTORS THAT AFFECT THE GUT
Like much else, the gut microbiome may well be most malleable in early life. Pets, cleanliness (or lack of!), diet and pre/probiotics all contribute to establishing the busy ecosystem of the gut. And, like any great rainforest, it must be carefully maintained. In practice, this means supporting a diverse and well-populated gut tract; the microbial populations of our body surfaces are constantly evolving throughout life, even after the formative years of early childhood.
This spells out a need to return to the outdoors and re-connect with the microbial ecosystem that surrounds us. After developing over a few hundred of thousand years in unison with the human host, the relatively rapid shift to the sterile, ultra-clean urban environment that has taken place over a few hundred years has been dramatic in the eyes of the microflora. Whilst we have crafted our surroundings to suit our needs, we have overlooked the needs of our microbiome. As a consequence, colonization and growth has been hindered and the healthy microscopic guests that call our gut home are being displaced by their damaging and more resilient cousins.
We could attempt to limit impact of modern living on the microbiome by spending more time outdoors, practicing natural processes such as vaginal birth, breast feeding and other intimate interactions that involve close contact– even kissing! The body will likely welcome a shift away from the fastidious, ultra-clean, man-made environments of their schools, hospitals, homes and cars. Whist this doesn’t mean a return to the somewhat outdated practices of mothers pre-chewing their baby’s food, the key is to keep their diet diverse with lots of prebiotic and probiotic building foods and to allow more room for outdoor fun; tree bathing (that’s also a thing!) and chasing squirrels in the park could quite possibly be the new health trend… don’t joke, I can see it now….
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Chef and Health Consultant Gutsy Flora is on a mission to absorb and share everything she loves about Gut Health. A topic she is desperately trying to keep up with and is dedicated to the cause of translating information for the Gutsy readers. Her expertise are in fermenting and supporting people to lead a holistic lifestyle. Her favourite topics of interest are the gut-brain-axis and whole foods relating to the gut microbiome. Flora works with private clients to inspire and guide them in making truly sustainable adjustments towards a healthier balance that suite their lifestyle.