1 of 8

LESSON 1 · Your Gut: The Hidden Brain

Your Inner Ecosystem

Your gut contains roughly 38 trillion bacteria — more microorganisms than human cells in your body. This community of bacteria, fungi, and viruses is your microbiome, and it functions like an organ you never knew you had. It produces vitamins, trains your immune system, and communicates directly with your brain.

No two microbiomes are exactly alike. Yours was shaped by how you came into the world, the medicines you have taken, and — most of all — what you eat every single day.