Mind altering microbes: How the microbiome affects brain and behavior

Bacteria, more commonly referred to as "germs" or "bugs", are far more influential in our overall health than we realize.

We tend to focus on the negative nature of infectious germs, but there are many others that actually bolster our health. Dr. Hsiao presents the positive implications gleaned from her research which suggest that our survival is far more in debted to microbes than we know.

“You could also ask who’s in charge. Lots of people think, well, we’re humans; we’re the most intelligent and accomplished species; we’re in charge. Bacteria may have a different outlook; more bacteria live and work in one linear centimeter of your lower colon than all the humans who have ever lived. That’s what’s going on in your digestive tract right now. Are we in charge, or are we simply hosts for bacteria? It all depends on your outlook.”

― Neil deGrasse Tyson, Space Chronicles: Facing the Ultimate Frontier

Source: http://ed.ted.com/on/akg9D3p6