Where would we be without our gut bugs? These bacteria help us do everything from digesting food to recovering from disease, but scientists are still learning exactly what gut bugs do, and even how to study them.
In the latest report from this inner frontier of science,Lawrence David, formerly a graduate student at the Massachusetts Institute of Technology, and his adviser, Eric Alm, tracked their own bodily functions—which largely meant studying their poop and pee—to see what might alter the colonies of bacteria that live in their guts. (Related: "Why Has This Really Common Virus Only Just Been Discovered?")
They used cutting-edge DNA analysis and also perhaps the oldest health metric ever used by humans, studying their own feces. The results of their 2009-2010 adventure are published Thursday in the journal Genome Biology.
National Geographic talked to David, now an assistant professor at Duke University in Durham, North Carolina, about the experience and what he learned.
For the most part, were gut bugs pretty stable across time?
The most abundant species you would see for days, weeks, months. We couldn’t find very many lifestyle variables that would cause a new species to show up or disappear.
You write in the study that the biggest change you saw was from an accidental food poisoning.
In about a week, about half the [bacterial] species that had been very abundant became much, much, much less abundant. Many of them dropped to at or below our detection limit.
You also saw some quick changes in gut bugs from eating fiber. Were you intentionally eating fiber to see what would happen?
The subjects were instructed not to alter their diets. The power of our study was that we weren’t telling people, “You have to eat fiber bars for this one week and then we’re going to analyze it.” We said, “Just live your life the way you normally would and we’ll see what we can learn.”
Wait a minute. You refer to the people in your study as “the subjects,” but weren’t they really you and your adviser, Eric Alm?
As scientists, we were trying to be as impartial as possible in how we analyze our data and interpret it. In many ways it was a pilot study. We were trying to figure out what kind of host actions could be tracked and what was feasible to look at in people over time. In a pilot study, we didn’t want people doing things that we ourselves wouldn’t really be comfortable doing.
Are there metrics that will be too difficult to ask future subjects?
Now I know that tracking things like urination [is too onerous]. Compliance would probably be abysmal.
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