© University of Pittsburgh
"We all have those urges — like if you ever you just feel like you need to eat a salad or you really need to eat meat," said Kevin Kohl, an assistant professor in the Department of Biology in the Kenneth P. Dietrich School of Arts and Sciences. "Our work shows that animals with different compositions of gut microbes choose different kinds of diets."
Despite decades of speculation by scientists about whether microbes could influence our preferred diets, the idea has never been directly tested in animals bigger than a fruit fly. To explore the question, Kohl and his postdoc Brian Trevelline (A&S '08), now at Cornell University, gave 30 mice that lacked gut microbes a cocktail of microorganisms from three species of wild rodents with very different natural diets.
The duo found that mice in each group chose food rich in different nutrients, showing that their microbiome changed their preferred diet. The researchers published their work today in the journal Proceedings of the National Academy of Sciences
While the idea of the microbiome affecting your behavior may sound far-fetched, it's no surprise for scientists. Your gut and your brain are in constant conversation, with certain kinds of molecules acting as go-betweens. These byproducts of digestion signal that you've eaten enough food or maybe that you need certain kinds of nutrients. But microbes in the gut can produce some of those same molecules, potentially hijacking that line of communication and changing the meaning of the message to benefit themselves.
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