Your esophagus stretches down from the back of your mouth to your stomach. It has a soft lining surrounded by muscle that helps push little lumps of food to your belly. A low or acidic pH in your esophagus can cause damage to the lining. A normal pH in the esophagus is between 4 and 6 -- meaning slightly acidic rising toward neutral. A pH lower than 4 often suggests a gastrointestinal problem such as acid reflux.
Your esophagus helps ease food and water into your stomach -- but it doesn't digest food using digestive acids. In healthy people, acids are confined to the stomach where protective enzymes and thicker stomach walls saves the organ from damage. Enzymes in saliva and in the esophagus do start to break down food, but they don't require an acidic environment to do so. In some cases, acid from your stomach might raise the pH of your esophagus.
Conditions such as acid reflux and GERD release stomach acid up into the esophagus. This causes a burning sensation behind your breastplate, often referred to as heartburn. The burning feeling is often the acid damaging the lining in your esophagus. Stomach acid is often as low as pH 2.0, meaning very acidic. GERD stands for gastro-esophageal reflux disease -- a more persistent version of acid reflux.
If your doctor thinks you may have GERD or a similar condition they may ask you to undergo an esophageal pH monitoring test. The test involves passing a very thin tube down your esophagus and into your stomach. You keep the tube in place for a full day. After 24 hours, a sensor records the acidity levels in your esophagus. The test shows the general pH conditions. A low pH of 4.0 or less may suggest that you have acid reflux or similar digestive issues.
You probably won't need to check your esophageal pH and acid levels unless you frequently experience pain after eating. Most people might have a little acid reflux every so often. It could be triggered by a particularly large meal or a reaction to a specific foodstuff. GERD is a more regular leaking of acid into the esophagus. If you often feel heartburn sensations, speak to your doctor to arrange a pH test.