What Causes Heartburn
Many people want to know what causes heartburn and the best way to understand how it occurs is to get an idea of the anatomy of the digestive system, at least from the mouth to the stomach. This will also help to explain why heartburn is called gastroesophageal reflux disease (GERD).
When food enters your mouth, it travels to the stomach through a tube called the esophagus. The esophagus is lined with muscle and at the very bottom, where it meets the stomach, the muscle thickens to create a valve.
This valve is called the lower esophageal sphincter (LES) and its job is to stay closed except when food needs to enter the stomach. When it seals tight, it prevents acid from backing up from the stomach into the esophagus.
When it weakens, for whatever reason, this acid backs up and causes the symptoms of heartburn.
The term gatroesophageal reflux means that contents from the stomach flow backward into the esophagus and cause damage. Even though the problem is due to the sphincter, the condition is often treated by reducing the amount of acid that flows backwards out of the stomach.
Thus, we don’t always treat what causes heartburn directly, but rather treat other components of the digestive system in order to bring about relief.
So what causes heartburn is relatively straightforward. It is simply a failure of the LES to keep stomach acid in the stomach where it belongs. The question then becomes, what causes the LES to fail to keep acid in the stomach? The answer to that is twofold:
- The LES itself may be weakened
- The pressure on the LES (up from the stomach) many be increased
There are several things that can contribute to either of these factors and thus many ways to answer the question, “what causes heartburn?” Here are the most common answers to that question.
The LES can be weakened by medications, drugs, changes in the body, genetic conditions, and even certain foods. Medications that commonly affect that LES are blood pressure medications like beta-blockers and calcium channel blockers, asthma medications like albuterol, certain birth control pills, the older class of antidepressants called tricyclics, and drugs taken for insomnia or anxiety.
What causes heartburn by weakening the LES is not limited to medications. Many foods also reduce the effectiveness of the LES. Such foods include tomatoes, onions, peppermint, caffeine, chocolate, and alcohol.
Though not a food, nicotine and other chemicals in cigarettes are also known to weaken the LES.
Scleroderma is a condition that affects muscles and makes them become fibrotic (scarred). In so doing, scleroderma weakens the LES. Other diseases that can weaken the LES include hiatal hernia and certain neurologic diseases.
Changes in the body as a result of pregnancy and obesity can also cause heartburn by putting more pressure on the abdomen and thus the stomach. Even though the LES is “normal,” it is unable to cope with this increase pressure.
In these cases, losing weight or giving birth can both reduce the strain on the LES and therefore lead to a resolution of symptoms.
In basic terms, heartburn is a result of acid entering the esophagus. The acid causes the symptoms of heartburn, but it is the failure of the LES to keep the acid in the stomach that is the ultimate cause of heartburn. We treat the condition, in most cases, by reducing the amount of acid in the stomach.