Several months ago, New York University microbiologist Martin Blaser published a paper detailing the fantastically rich bacterial ecosystems that live on our skin -- hundreds of species varying between people and over time, having ostensibly evolved over thousands of years to ... do ... something.
Scientists aren't quite sure about what our bacterial robes do, just as they're only beginning to understand the bacterial ecosystems of our stomachs -- or, for that matter, all the bacterial ecosystems in our bodies. In purely numerical terms, bacteria account for about 90% of the cells in the human body.
I had a chat with Dr. Blaser this morning and asked him what the antibacterial regimes of a modern lifestyle might do to our unappreciated microbial partners (and, indeed, to us). His answer:
I don’t know the answer, but my suspicions are the same as yours. In the "Who Are We" paper, I make a series of six postulates. One of them is the microbes that live in the human body are quite ancient. They've been with us for a long time, been selected because they help us, and as a result of 20th century practices are changing, all over the body. Just as the world is very aware of the concept of global warming, which is a macro ecological change, I postulate there are micro ecological changes parallel to that.
I hate to be so pessimistic, but there’s a perfect storm coming our way. One of the main roles of our normal [personal bacteria] is that they protect us against invaders. If they’re changing, we’re lacking a certain level of protection. The body is loaded with microorganisms; we sampled skin, but it’s true anywhere there's a surface. It's estimated that the number of microbial cells in the human body exceeds the human cells by at least 10. That’s in all of us every day. At a biological level, we’re 90% them and 10% us -- and the subpopulations seem to be changing.
