May 032011
 

Saturday I wrote a post about how I wasn’t aware of what was going on in my body, and how unsettling that felt. So unsettling, in fact, that I wasn’t able to write the post I had been planning for several days, and had to gaze intensely at my navel for a whole weekend instead.

That was probably a good thing, because it gave me some new insight into this post. Navel gazing isn’t all bad. Turns out there’s some pretty interesting stuff in there. As you’ll see if you read on.

Last fall I translated an article by Daniel Saraga for Reflex Magazine about the gazillions of bacteria we have living on and in our bodies. The title (in English) was “Me, Myself and I – and a million other germs.” It should actually have been “Me, Myself and I  – and 100 trillion other germs.”

That’s right. A human body has about 10 trillion cells in it. And that very same human body (yours, for example), is also home to 100 trillion bacteria. Your mouth, your nose, your armpits, your navel, your skin and especially your gut are teeming with thousands of different species of bacteria. If you could separate out all those bacteria from the rest of you, they’d weigh 2 kilos. (Before you start swigging Lysol, be warned that without them, you’d be dead. They secrete enzymes that are critical for digesting food.)

The science geeks among you have probably already read about this in the news.  For the rest of you, Ed Yong has written a really great overview in his blog, Not Exactly Rocket Science.

We’re not so much organisms as we are ecosystems. Each of our bodies is like a whole planet to the bacteria that have colonized us. We have deserts (skin), tropical rain forests (mouths, noses, butt cracks), deep oceans (intestines). Each of these zones harbors particular species of bacteria. And my armpit bacteria are different from your armpit bacteria, but mine and yours both stay remarkably stable throughout our lives. Babies get their very first bacterial colonies at birth, on their way out of the vaginal canal. Eureka! A new host! (If they’re born by C-section, the bacteria that set up shop in their tiny guts are totally different.)

Recent research (a.k.a fun and games analyzing s%#t samples) reveals that human gut communities fall into three basic types, that hold across all continents and all nations. The New York Times report on the discovery compared it with the identification of human blood types: “Blood type, meet bug type.” (What a great sentence! Carl Zimmer, you are my hero.)

It’s totally unlike the human genome, which is highly geographical. Genetically, people in Japan are more like other people in Japan than they are like people in Finland. But gut bacteria don’t follow those rules; a Japanese can, and does, have the same basic gut community as a Finn. The author of the study indicated that people with a certain disease all had the same bug type. (But he wouldn’t reveal what the disease was.)

This is shocking news. Could it be that we’ve been taken for a huge ride here? We thought we were the top guns on this planet! We thought it was all about us! We thought our bodies were vehicles for our splendiferous brains!

No, silly. We are being maintained. We exist simply as biomes for colonies of established bacteria. Our brains probably just evolved as the best way for our bacteria to ensure that they will continue to have thriving hosts, generation after generation.

Think about it. Thanks to our outsized cortexes we are better fed than ever before. We live longer. We have figured out how to fight off nasty invading bacteria and viruses that threaten our interior colonies. It saves them the job! We thought disease was about us, about our genes. It could very well involve a batch of rogue bacteria. Guerilla germs, hiding out in the hills of our small intestine.

Ed Yong explains how our gut bacteria could even be manipulating us to their own ends, sending out signals that make us hungrier and encourage us to eat more and store up fat. What’s to say that all our behavior doesn’t have at its ultimate source some bizarre bacterial need? Or some complicated internal competition? A sort of bacterial Olympics, taking place in our nostrils?

I’m afraid the crowdsourcing thing wasn’t our idea after all. Yes, it seems we are being crowdsourced by three bacterial fiefdoms, and have been for millenia. They’ve farmed out all their needs to humans the world over, and we had absolutely no idea. And it will likely continue no matter what we end up doing to the planet. I’m sure they’re rooting hard for the space program, so they can make sure we move to Mars and they don’t lose these precious ecosystems they have worked so hard to develop. They’re probably holding summit meetings as we speak, on bathroom floors at NASA.

Come to think of it, I wonder if Al Gore and W. have different bug types? Gore’s gut is going “We’ve gotta stay on this planet, guys, it’s been great so far!” and W.’s is saying “No, dudes, let’s scrap it and try another. Innovate or die!” Who’s progressive in that scenario?

And the worst thing is that there’s not a damn thing we can do about it. Without our bacterial bosses, we’re just defenseless shells.

It’s enough to make my blood pressure spike.

  4 Responses to “Crowdsourcing, Part III”

  1. I just read your blog and am heading off to contemplate my makeup – and I ain't talkin' blush, scara and stick! Seriously funny food for thought – thanks.

  2. So you're saying if some people are destined to be fat, it's not genetical but "bug-ical"? But would you say that it's still "stays" in the family. since, a mother basically shares her bacteria with her child at birth?

    Very interesting post in any case!

  3. Natalie –
    The evidence is looking good that weight (particularly obesity) is indeed linked to your gut fauna. The link for Ed Yong's blog describes an experiment that was done using sterilized mice – the ones that got the "fat" gut fauna got obese, even if they ate exactly the same and exercised the same as the mice that got the "regular" gut fauna (who didn't gain weight). Now how can we manipulate this to solve the obesity epidemic? Figure that out & you're a millionaire.

  4. Natalie -
    I realized that answer didn't answer your question, which was a good one. I don't really think that the "Bugs" you have are genetic — what I've read indicates there is a disconnect between genetic inheritance and these three main bug groups. But then it does say the mom transmits some bacteria at birth. (but only in vaginal births). I'm not sure they really know this yet.

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