Gut health | An introduction to the microbiome

4 fascinating facts about the remarkable goings on in your gut

The latest buzz in health now is how to manage the state of your gut and the many microbes that populate it. I think about my microbiome often (slightly odd I know). More often, in fact, than I think about wandering off to the chocolate shop around the corner to buy just one more tiny bar of handmade deliciousness. That’s a daily struggle that I often lose. The gut thing is a different sort of puzzle, seemingly equally out of my control, and one I haven’t quite got my head around yet.

The latest scientific information (which admittedly is in its infancy, as we have only recently begun to pay attention to our intestines and their occupants) has now decided that much of the state of our health is down to the trillions of microbes that live there and do much of the work breaking down our food as a part of the process of feeding themselves.

Gut statistics are in their early stages, so the information that’s out there sometimes confuses rather than educates.

Back to Basics

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1 What is gut health? What are microbes?

In essence, the gut debate seems to be about the colonisation of our world by microbes. What are they? Where do they come from and what are they doing? I am not sure we really know. There are thought to be more than a million types of bacteria in existence on Earth. Possibly many more. They have set up shop in every crack and crevice of this planet we call home.

They are minuscule, and invisible to the human eye. Microscopic, but extremely hardy, they can adapt to the toughest environments: total darkness, blazing heat or freezing cold. Damp, humidity, no water at all: none of it is a problem to these multiplying multitudes.

A few settlers have come to live inside man himself. But the term few is relative. Your gut alone is host to innumerable (that means numbers without count, and I really, really don’t think it would be possible to count them, there are so many) viruses, yeasts, bacteria, algae, moulds, funguses, archaea and protists (ever hear of the last two? Me neither!) alongside hordes of other life forms you never knew existed.

These are your microbes and there are estimated to be a flabbergasting 100 trillion of them, living alongside and inside you.

As a group, microbes are described as your microbiota and the term microbiome refers to your own personal microbe ecosystem made up of individual varieties and quantities of microbe types specific to you.

2 Where do microbes live?

The vast majority of microbes hang out in your gut, in your colon and small intestines. But they are also all over your skin: in your mouth, your nose and in your stomach, lungs and vagina. Everywhere really. The only places they don’t seem to colonise much are the blood and your lymph fluid.

3 What is a typical microbiome?

The science of the human microbiome is in its very early stages, and many of the fundamental answers remain unanswered. What’s in your gut, however, is not thought to be random muddle of microbes, but a particular set that have particular functions and purpose, even if we aren’t currently quite clear about what they do or why they do it.

There are hundreds of thousands of different microbes that can be found all over the earth, but only around 1,000 of them are found in us. The same ones pop up time and time again in humans. On average each individual will have a combination of around 160 bacteria making up his microbiome (Qin et al, 2010). And each area of the body has different inhabitants adapted for their particular environment. Skin microbes tend to be similar in all of us, but very different, for example, to the microbes found in the gut.

So it seems that each of our microbiomes are different but similar, like snowflakes or fingerprints are similar but different. You may have a slightly different make up of human adapted microbes than your neighbour, but once you have developed your own collection, they don’t change much after your early childhood years.

4 How did my microbiome develop?

Mainly from other human beings. Each of us inherits around 20,000 genes from our parents that determine our physical and mental characteristics. They give us blue eyes, or curly hair and a specific temperament. But we also inherit around 8 million microbiome genes (all the genes of the viruses, bacteria, fungi) from them too, as well as from other people, topped up by our environment and daily diet. For every human gene you have, therefore, you have around 300 non-human genes with all sorts of capabilities and functions. And those non-human genes look like they may be running many of our bodily systems.

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A fifth fascinating fact

Invisible and minuscule though they are, all those microbes add up to the equivalent of 2.5lbs of your body weight. In liquid terms, that’s around 3 pints of milk.


Star Trek or science?

This is Star Trek in real life. You may not be who you thought you were at all. You are definitely carrying other passengers in your personal starship. Your body has 3 times more bacterial cells than human cells. And as viruses alone outnumber bacteria in the human gut 5 to 1, the size and power of your microbiome is truly galactic - comparable in numbers to the stars and planets of outer space.

As science now knows far more than it used to about the planets and galaxies of outer space, so presumably over the years that come, it will find answers for us about our inner space. The discovery of the microbiome is up there with the discovery of fire. Game changing for mankind. Let’s hope we don’t have to wait too long for the answers. Your health, and mine, may well depend more than we think upon our microbial visitors and what they get up to in our gut.

Watch this space... The Microbiome - Parts II and III are coming soon.


Written by health advocate Sara Davenport, who founded one of the UK's largest breast cancer charities, The Haven, twenty years ago. With Reboot Health, Sara aims to bring the best preventative and curative health solutions ranging from nutrition, alternative therapies, fitness and conventional medicine.

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