An estimated 20% of Americans suffer from GERD, a chronic form of acid reflux that goes beyond occasional heartburn. Here's ...

Heartburn, which usually presents as a burning sensation in the chest, is one of the main symptoms of indigestion and is caused by acid ... a healthy diet that can guard against reflux.

But if the lower esophageal sphincter opens too often or does not close tight enough, stomach acid can reflux, or seep back into the esophagus, causing the burning sensation we know as heartburn.