Once food is swallowed it is transported through the oesophagus to the stomach by waves of muscular movement called peristalsis. Once it arrives in the stomach, the force of gravity takes over, keeping the food from moving back up the oesophagus.
In reflux, gastric acids from the stomach move upwards into the oesophagus, against the effects of gravity. Unlike the cells of the stomach, the cells of the oesophagus are not acid-resistant, so their exposure to these gastric juices results in the characteristic burning pain, and over the long term may lead to inflammation and damage to the oesophageal tissue.
Contributing factors may include:
- Hiatus hernia, which involves the displacement of part of the stomach up through a hole in the diaphragm
- Weakness of the sphincter (valve) between the stomach and oesophagus
- Abnormal emptying of the stomach after eating
Factors that may trigger or aggravate reflux include:
- Eating too much
- Spicy foods
- Fatty foods
- Soft drinks and other carbonated beverages
- Tomato sauce
- The use of certain medications (including some blood pressure drugs and some sedatives)
- Being overweight or obese
- Wearing tight clothing while eating
- Lying down after eating