Immigrants arrive with flourishing gut microbes. Then America’s diet trashe

An empire of germs dwells inside you, trillions strong. About a half-pound of bacteria plus their genes make up our microbiome. Though each microbe is small, a healthy and diverse microbiome is mighty. Its influence, studies suggest, spans the human condition — from mood swings to weight gain.

Immigrants arrive with flourishing gut microbes. Then America’s diet trashe