The Vagus Superhighway

The vagus nerve is the longest of the nerves that run straight out of your brain. It reaches all the way down to your gut and carries traffic in both directions.

But the traffic is lopsided. Roughly 80% of its fibers run upward, from gut to brain. Your gut talks to your brain far more than your brain talks back.

Some of that upward traffic is an alarm. When your gut gets inflamed, it signals the brain along the vagus nerve, and the brain answers by telling the body to release anti-inflammatory compounds.

This loop is a safety valve. It keeps your own immune defenses from overreacting and damaging healthy tissue in the process.