What Causes Reflux?
When you eat, food passes from the throat to the stomach through the esophagus. Once food is in the stomach, a ring of muscle fibers prevents food from moving backward into the esophagus. These muscle fibers are called the lower esophageal sphincter, or LES.
If this sphincter muscle doesn't close well, food, liquid, and stomach acid can leak back into the esophagus. This is called reflux or gastroesophageal reflux. This reflux may cause symptoms, or can even damage the esophagus. Obesity, cigarettes, and possibly alcohol also increase the chance of GERD.
Gastroesophageal reflux disease, commonly referred to as GERD or acid reflux, is a condition in which the liquid content of the stomach backs up or refluxes into the esophagus. The liquid that enters the esophagus (regurgitation) can damage the lining of the esophagus although visible signs of inflammation occur in a minority of patients. The regurgitated liquid usually contains acid that is produced by the stomach.