What causes Barrett's esophagus?

Barrett's esophagus is caused by years of chronic heartburn (gastroesophageal reflux disease - GERD). When the esophagus (swallowing tube) is exposed to stomach acid and bile backwashing into it, these substances can cause injury to the normal squamous lining of the esophagus. Esophageal injury with inflammation is called esophagitis. In about 10% of those who have severe GERD, if acid injury to the esophagus continues over many years, the injured normal squamous lining of the esophagus does not grow back. Instead, it is replaced by a new abnormal lining called Barrett's esophagus (specialized intestinal metaplasia of the esophagus).

No one knows why Barrett's esophagus develops in response to acid injury to the esophagus. Barrett's esophagus produces mucous, like normal stomach lining, and therefore may resist acid injury better than the normal squamous lining of the esophagus. It may be the body's attempt to protect the esophagus against continued injury by chronic GERD. In fact, some people who have Barrett's esophagus report a past history of heartburn but none in recent years. This has led some researchers to believe that the development of Barrett's esophagus may relieve GERD (heartburn) symptoms in some people. No one knows why some people who have severe GERD develop Barrett's esophagus and why others do not.