Viewpoint: How do our bacteria help us?

The bacteria that live in and on us might be responsible for whether we are healthy or unhealthy, and even whether we are fat or thin, writes Ed Yong.

I was born just under 30 years ago. That moment, just before I emerged into the world, was the last time in my life that I would be completely sterile.

Inside the womb, it was just me and mum - a universe of two. But outside, there was a world of bacteria and other microbes, and as soon I entered that world, they became part of me. They colonised my skin. They set up shop in my guts. And these passengers are an essential part of my life.

These hitchhikers, and the genes they carry, are known as the microbiome. We all have them, and they are legion.    Full Read