My Microbiome Made Me Do It

Yes, the 100 trillion bacteria and other microbes that reside in your body certainly outnumber you. Now comes a group of researchers who suspect that they may also outsmart you–influencing your behavior in ways that are good for them first, you second. Carl Zimmer reports in the New York Times on the possibility that our microbiome is a puppetmaster, and we are, yes, the puppets. After all, it’s well known, says Zimmer, that “some species of fungi infiltrate the brains of ants and coax them to climb plants and clamp onto the underside of leaves. The fungi then sprout out of the ants and send spores showering onto uninfected ants below.” There is also plenty of evidence that our gut bacteria make some of the same chemicals that our neurons use to communicate with one another, such as dopamine and serotonin. Yes, they’ve hijacked our communications systems. God only knows what they’ll make us do next. Read what Zimmer says here: “Adding certain species of bacteria to a normal mouse’s microbiome can reveal other ways in which they can influence behavior. Some bacteria lower stress levels in the mouse. When scientists sever the nerve relaying signals from the gut to the brain, this stress-reducing effect disappears…Some experiments suggest that bacteria also can influence the way their hosts eat. Germ-free mice develop more receptors for sweet flavors in their intestines, for example. They also prefer to drink sweeter drinks than normal mice do.” You get the picture, but only get it because your microbiome doesn’t care how much you know. It only cares that bring it some more cheese and another glass of Rioja, the good stuff this time.