Sublime

recent advances in microscopy have revealed the gut to possess 100 million neurons and thirty neurotransmitters, effectively making it a second brain as big as a cat’s that works in tandem with the one up top.59 This so-called gut–brain axis forms the core, not just of how we eat, but of how we sense, and make sense of, the world.

Harvard Medical School was and is at the forefront of the neuroscience revolution,

Our microbiome is connected to our moods and behavior, communicating with our brain through the vagus nerve, which provides a direct line between brain and gut, as well as through the various chemicals it produces and releases into our bloodstream.

When the alarm bell of the emotional brain keeps signaling that you are in danger, no amount of insight will silence it.

Our gut—and its inhabitants—therefore serves as a sort of “training camp” for our body’s immune system.