Nurturing Our Microbes
Stewardship of the life teeming within us can pay health dividends
By Janet Raloff
Each of us is a metropolis. Bustling about in everyone’s body are tens of trillions of microbes. Some are descended from starter populations provided by mom during birth. Additional bacteria, yeasts, and other life forms hitchhike in with foods. By age 3, everyone’s gut hosts a fairly stable, yet diverse, ecosystem.
Most of the tiny stowaways hide out in the gastrointestinal tract—the gut-stealing a share of everything we eat or drink. But that’s only fair, because most of these bugs give as good as they take, explains microbiologist Jeffrey I. Gordon. They not only help us digest food, he says, but they also harvest nutrients, manufacture certain vitamins, kill germs, neutralize bacterial toxins, and modulate the immune system. Sickness, antibiotic therapy, or stress, however, can disrupt the ecological balance among gut dwellers—known as flora—diminishing their benefits.