How Gut Bacteria Tell Their Hosts What to Eat
By suppressing or increasing cravings, microbes help the brain decide what foods the body “needs” Colored scanning electron micrograph (SEM) of Lactobacillus bacteria. Credit: Steven Gschmeissner Getty Images Scientists have known for decades that what we eat can change the balance of microbes in our digestive tracts. Choosing between a BLT sandwich or a yogurt parfait for lunch can increase the populations of some types of bacteria and diminish others—and as their relative numbers change, they secrete different substances, activate different genes and absorb different nutrients. And those food choices are probably a two-way street. Gut microbes have also been shown to influence diet and behavior as well as anxiety, depression, hypertension and a variety of other conditions. But exactly how these trillions of tiny guests—collectively called the microbiome—influence our decisions on which foods to stuff into our mouths has been a mystery. Now neuroscientists have found that specific types of…