Benefits of Eating Dirt

We evolve to gain microbial experience that calibrates our immune system, says expert Mark Davis in a short video from Stanford Medicine. This is why babies constantly put things in their mouths – they are calibrating their immune systems.  Similarly, we need to hear language in order to speak it well. And, interestingly, the environment (including where we live and what we eat) plays a larger role in shaping our immune system than our genes, based on studies with identical twins.