What Causes GERD and Heartburn?
The food a person swallows travels from the mouth to the stomach through a hollow tube called the esophagus (the food pipe). Before entering the stomach, food must pass through a tight muscle at the lower part of the esophagus called the lower esophageal sphincter (LES). The LES is a defense mechanism that prevents food from traveling backward into the esophagus.
In the stomach, stomach acid assists in continuing the digestion of food. This acid is very strong and can damage most parts of the body. The stomach is protected from its own acid by a special mucous layer. The esophagus, however, does not have any such special protection. If the LES does not close properly, the lower part of the esophagus can be damaged by stomach acid and GERD can occur. When this happens, a person may experience heartburn.
Conditions such as hiatal hernia, pregnancy, obesity, or diabetes may predispose individuals to reflux disease. Also certain medications (beta agonists, calcium channel blockers, nitrates, anticholinergics) and foods (fatty meals, alcohol, coffee etc.) can cause transient relaxation of the LES muscle, which renders the LES inadequate to prevent reflux into the esophagus. As a result GERD develops.
Infants, particularly premature infants, commonly experience reflux disease, and adults over the age of 40 have a higher prevalence of GERD.