【英语时差8,16】有益细菌（在线收听）

Some of the microbes in our gut are there for a valid reason. Well, there’s a bacterium called thetaiotamicron in the intestines that lives off the food we eat. In return, it helps us digest certain foods by breaking them down into sugars and vitamins. This particular microbe may also regulate certain intestinal genes and help create new blood vessels. Finally, it helps produce a chemical that kills disease-causing bacteria. Consider this. Scientists created mutant mice without any germs in their intestines. These mice ended up getting sick a lot and needed to eat much more than normal mice with intestinal bacteria in order to gain weight. In fact, we probably couldn’t do without them.