Gut Check

What is the human microbiome? Specifically the human gut microbiome? It’s like a whole universe inside your belly—parasites, fungi, bacteria and viruses—trillions of them!

Uncovering the human microbiome represents a new frontier in science. Thanks to new technology, we’re beginning to understand what these microscopic organisms do, how they do it, and why they exist inside of us.

Last Friday, the awesome Bay Area Science Festival presented “Gut Check: The Hidden World of Microbes.” The panel included two UC San Francisco researchers—our friend, Joe DeRisi, and Michael Fischbach—and science writer extraordinaire, Carl Zimmer. If you follow Zimmer’s Discover blog, The Loom, you know that he loves anything tiny and gross—parasites, bacteria, fungus, the like—so we knew it would be a juicy discussion.

DeRisi developed the ViroChip—a technology that allows scientists to scan samples for several different viruses—over 10,000 things at a time—and bacteria, fungi, and parasites. When Fischbach looks at us, he sees the 100 trillion microorganisms living inside us. These microorganisms make up 10% of our genes, so he uses genome-sequencing technology to study all of them at once.

The following are some of the topics discussed by the panel:

Antibiotics and other Good Bacteria

Fischbach got into human microbiome research looking for drugs. Your gut (and skin and oral) bacteria are natural antibiotics and statins (cholesterol-lowering drugs). They could also possibly control obesity and diabetes. Microbes support your immune system and metabolism, and many of the bacteria in your gut create neurotransmitters, fueling research about how our gut bacteria affect our brains.

Fischbach pointed out how current antibiotics take a “carpet bomb” approach—killing all bacteria in our bodies, good and bad. With more research, he believes that specific good bacteria could target specific bad bacteria—taking a more “scalpel” approach to antibiotics.

Tending the Garden

Among the microorganisms in our body, there are those that help us digest food and create energy and those that just feed themselves. Insoluble fiber may keep us healthy, but we’re not actually absorbing any of it—the microbes keep it all to themselves! As Zimmer said, “You’re not eating it for yourself, but rather tending the garden.” The garden of gut flora.

The Virome

Did you know we have seven trillion viruses in our body when we’re healthy? Some of these viruses attack us and some attack other viruses or bacteria. And, are you ready for this? DeRisi can’t “think of any example of a beneficial virus.” So what are they all doing there? DeRisi has no clue, and every time he sequences he finds new viruses, wondering what role they might play.  Bringing up the question, is there a virome in addition to the biome of the human body?

With trillions of viruses and new ones evolving, does DeRisi lay awake at night in a panic? No. (Phew!)

So whether riding BART or keeping your child in a germ-free environment, the message of the panel was don’t worry about these tiny organisms (at least, for now). More research is needed to find out exactly what kind of tug of war is going on inside of our bodies.