I, Superorganism

Every human body carries a secret cargo: a huge population of microorganisms living in the mouth, on the skin, in the gut. They help digest our food. They make essential vitamins.

They break down toxins and metabolise drugs. They exert an invisible influence on our hormones, our immune systems, perhaps even our brains. This is the human microbiome - a living, shifting system of previously unimagined importance and complexity.