10% Human: How Your Body's Microbes Hold the Key to Health and Happiness

disruptions to the body’s microbes were behind gastrointestinal disorders, allergies, autoimmune diseases, and even obesity. And it wasn’t just physical health that could be affected, but mental health as well, from anxiety and depression to obsessive–compulsive disorder (OCD) and autism. Many of the illnesses we accept as part of life were not, it

In 2010, a huge study was conducted by a team of hundreds of scientists who hunted through the genes of a quarter of a million people in the hope of finding some that were associated with weight. Astonishingly, they discovered just 32 genes in our 21,000-strong genome that seemed to play a role in weight gain. The average difference in weight betwe

I used a citizen-science programme, the American Gut Project, based at the laboratory of Professor Rob Knight at the University of Colorado, Boulder. Available to anyone around the world for a donation, the AGP sequences samples of microbes from the human body to learn more about the species we harbour and their impact on our health. By sending a s

Our own cells, though far larger in volume and weight, are outnumbered ten to one by the cells of the microbes that live in and on us. These 100 trillion microbes – known as the microbiota – are mostly bacteria: microscopic beings made of just a single cell each. Alongside the bacteria are other microbes – viruses, fungi and archaea.

Metabolic rates do vary from person to person, but it is actually overweight people who have the faster metabolisms, not lean people. It simply takes more energy to run a big body than a small one.

Acquiring the genes to do this is quick and easy for microbes, as their generation times, and therefore opportunities for mutations and evolution, are often less than a day.

Each of us contains communities of microbes as unique as our fingerprints.

With just shy of 21,000 genes, the human genome is hardly bigger than that of The Worm (C. elegans). It is half the size of the rice plant, and even the humble water flea outstrips it, with 31,000 genes. None of these species can talk, create, or think intelligent thoughts. You might think, as the scientists entering the Genesweep pool did, that hu

You are just 10 per cent human. For every one of the cells that make up the vessel that you call your body, there are nine impostor cells hitching a ride. You are not just flesh and blood, muscle and bone, brain and skin, but also bacteria and fungi. You are more ‘them’ than you are ‘you’. Your gut alone hosts 100 trillion of them, like a coral ree