What Causes Acid Reflux?

Causes

Anyone who a large amount of acidic foods can have mild and temporary heartburn. This is especially true when lifting, bending over, or taking a nap after eating a large meal high in fatty, acidic foods. Persistent GERD, however, may be due to various conditions, including abnormal biologic or structural factors.

Malfunction of the Lower Esophageal Sphincter (LES) Muscles

The band of muscle tissue called the LES is responsible for closing and opening the lower end of the esophagus and is essential for maintaining a pressure barrier against contents from the stomach. It is a complex area of smooth muscles and various hormones. If it weakens and loses tone, the LES cannot close up completely after food empties into the stomach. In such cases, acid from the stomach backs up into the esophagus. Dietary substances, drugs, and nervous system factors can weaken it and impair its function.

Impaired Stomach Function

A study showed that over half of GERD patients showed abnormal nerve or muscle function in the stomach. These abnormalities cause impaired motility, which is the inability of muscles to act spontaneously. The stomach muscles do not contract normally, which causes delays in stomach emptying, increasing the risk for acid back up.

Abnormalities in the Esophagus

Some studies suggest that most people with atypical GERD symptoms may (such as hoarseness, chronic cough, or the feeling of having a lump in the throat) have specific abnormalities in the esophagus. (In one study, such abnormalities appeared in 73% of patients who had atypical symptoms.)

Motility Abnormalities. Problems in spontaneous muscle action (peristalsis) in the esophagus commonly occur in GERD, although it is not clear if such occurrences are a cause or result of long-term effects of GERD.

Adult-Ringed Esophagus. This condition is characterized by an esophagus with multiple rings and persistent trouble with swallowing (including getting food stuck in the esophagus). It occurs mostly in men.

Hiatal Hernia

The hiatus is a small hole in the diaphragm through which the esophagus passes into the stomach. It normally fits very snugly, but it may weaken and enlarge. When this happens, part of the stomach muscles may protrude into it producing a condition called hiatal hernia. It is very common, occurring in over half of people over 60 years old, and is rarely serious. Until recent years, it was believed that most cases of persistent heartburn were caused by a hiatal hernia. Hiatal hernia may impair LES muscle function. Studies have failed to confirm evidence, however, that it is a common cause of GERD, although its presence may increase GERD symptoms in patients with both conditions.