YOU may have heard that your microbiome – the microbes that reside in your gut and elsewhere around your body – outnumber human cells by a whopping 10 to 1. Or that, combined, this incredible mass adds up to as much as 2 kilograms of your body weight. These notions have become widespread over the past few years as scientific and public interest in the microbiome has grown, with much of that interest concerning whether it could be the key to unlocking better health.
But as alluring as they are, these “facts” – not even close. Your ratio of microbes to cells is more like 1 to 1, and the microbiome weighs a much more modest 500 grams. Have we all got carried away with microbiome-mania?
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In this special issue, starting on “How the microbiome changes our idea of what it means to be human”, we put aside the hyperbolic – albeit catchy – factoids and take a clear-eyed look at what we really do, and don’t, know about the multitude of microbes living inside us, with a special focus on the gut.
What is true is that there is much we still don’t know – for instance, how to test whether your microbiome is in good health. And when it comes to the products and treatments that promise to give your gut microbes a boost, some claims should be taken with a generous pinch of salt.
Even so, as we delve into the research on the communities of bacteria, fungi and viruses that live in us, what we discover is truly amazing. It is increasingly clear that the microbiome has a hand in everything from our mood to our risk of arthritis. There are even hints that gut bacteria may be involved in some of our hardest-to-treat conditions, like Alzheimer’s.
Incredibly, our microbiomes are also shaped by those around us, which means the microbiome health of those we live with could be directly influencing our own. In fact, such is its reach in our lives, it is no exaggeration to say that what we are discovering about the microbiome challenges our very understanding of what it means to be human.
So there is no need to stomach the myths. The truth is far more interesting.
