You all know about intestinal permeability, or “leaky gut.” The job of the gut lining is to be selectively permeable, allowing helpful things passage into the body and preventing harmful things from getting in. Nutrients get through, toxins and pathogens do not. Leaky gut describes the failure of this vetting process. But what about “leaky brain”?

(This Mark's Daily Apple article was written by Mark Sisson, and is narrated by Tina Leaman)