As food passes from the mouth through the esophagus and into the stomach, the lower esophageal sphincter (LES) prevents the backflow of gastric content. The LES, which is a bundle of muscles at the base of the esophagus, is not under voluntary control and opens only in response to swallowed food. This ensures the unidirectional movement of food and isolates the stomach’s acidic environment from the sensitive lining of the esophagus.
When a small amount of partially digested food and stomach acid escapes back into the esophagus, a burning sensation, or heartburn, results. Occasional heartburn, especially following a large meal, is normal in healthy individuals. However, frequent episodes of heartburn potentially indicate gastroesophageal reflux disease (GERD), which, if left untreated, can damage the esophagus and organs of the oral cavity, and lead to respiratory problems and esophageal cancer.
Causes and Risk Factors
GERD results when the LES is weakened and not functioning properly, thus allowing the backflow, or reflux, of gastric juices into the esophagus. Body abnormalities and other factors including diet, obesity, and pregnancy can also contribute to GERD.
Diet and medications. Bloating of the stomach caused by overeating can exert outward pressure on the LES and cause acid reflux. Additionally, carbonated beverages, citrus fruits, tomato-based sauces, and fatty foods are among foods that may worsen the symptoms of GERD. Medications like calcium-channel blockers, anti-inflammatories, and narcotic pain relievers can also increase disease severity.
Obesity. An increase in body weight has been linked to increased risk of GERD - especially in the white population. Although the exact mechanisms are not fully understood, changes in gastroesophageal anatomy and physiology affecting LES function offer one possible explanation.
Pregnancy. 30-50% of pregnant women experience GERD symptoms, due to the maternal hormone progesterone. In addition to relaxing the uterine muscles, progesterone dampens muscle function in the LES.
Hiatus hernia. This abnormal condition occurs when part of the stomach pushes through an opening in the diaphragm and into the lower chest cavity. GERD is common in individuals with hiatus (also called hiatal) hernia.
Reoccurring heartburn is the most common symptom of GERD. The frequent exposure of other organs to stomach acids produces additional symptoms, including:
Gastroenterologists, doctors who specialize in digestive disorders, generally treat GERD symptoms prior to extensive diagnostic testing. For advanced or difficult-to-treat cases, various tests are performed to assess the upper gastrointestinal (GI) tract.
Upper GI series (barium swallow). This out-patient procedure uses X-ray imaging to examine the upper GI tract for ulcers, reflux, and physical abnormalities like a hiatus hernia. To aid visualization, the patient swallows a thick chalky liquid contrast agent containing barium.
Upper endoscopy. Endoscopy is a more invasive but accurate test for detecting GERD-related injuries and complications, such as ulcers, tumors, and inflammation. Once the throat is numbed, a small camera connected to a thin flexible tube is fed down the esophagus to look for injured tissue and collect samples if needed.
Esophageal monitoring. pH monitoring and manometry assess the environment and function of the esophagus. pH monitoring (often paired with upper endoscopy) measures acid levels and the extent of reflux in the lower esophagus, while manometry measures the strength of muscle contractions, including that of the LES.
Treatments options for GERD vary based on symptoms and include lifestyle changes, medications, and surgery.
Lifestyle changes. Mild cases of GERD can often be treated with simple modifications in daily habits. Avoiding smoking and foods that trigger acid reflux; eating sensible portions; maintaining a healthy weight; wearing loose-fitting clothing; and elevating the head during sleep are all ways to manage symptoms.
Medication. Both over-the-counter (OTC) and prescription drugs are available to treat GERD symptoms. OTC antacids provide temporary relief by neutralizing stomach pH. Prescription proton-pump inhibitors and H2-receptor blockers actually reduce acid production in the stomach, and are the most effective treatment option. Prokinetic agents and antibiotics (both by prescription) act by promoting stomach emptying. Coating agents (by prescription) form a protective film over the esophagus and stomach.
Surgery. Surgery is performed when GERD symptoms cannot be alleviated with medication, or lead to more serious health complications. The procedure commonly performed for GERD patients is a fundoplication, where the upper portion of the stomach is wrapped around the esophagus and sewn in place. This increases pressure on the LES and controls acid reflux. Endoscopic procedures that tighten up the LES are also performed, but are less effective.
Lifestyle changes that help treat GERD symptoms are also effective preventative measures. These include:
Avoiding foods and drinks that trigger acid reflux
Eating sensible portions
Maintaining a healthy weight
Wearing loose-fitting clothing
Elevating the head during sleep
“Gastroesophageal Reflux (GER) and Gastroesophageal Reflux Disease (GERD) in Adults”. National Digestive Diseases Information Clearinghouse (NDDIC). NIH. Sep 2013. Retrieved Mar 22, 2014. http://digestive.niddk.nih.gov/ddiseases/pubs/gerd/#cause.
“GERD: Heartburn and more”. The Harvard Medical School Family Health Guide. Harvard Medical School. Apr 2008. Retrieved Mar 22, 2014. http://www.health.harvard.edu/fhg/updates/GERD-heartburn-and-more.shtml.
“GERD”. MedlinePlus. NIH. Feb 2014. Retrieved Mar 22, 2014. http://www.nlm.nih.gov/medlineplus/gerd.html#cat1.
Lagergren, J. “Influence of Obesity on the Risk for Esophageal Disorders: Obesity and GERD”. Medscape Multispecialty. Medscape. Jun 2011. Retrieved Mar 22, 2014. http://www.medscape.org/viewarticle/743475_5.
Richter, JE. Review article: the management of heartburn in pregnancy. Aliment Pharmacol Ther. 2005. 22:749-57.
Tina is a Life Science Writer for a number of online publications, including Innerbody.com. Her expertise is in conveying complex scientific topics to diverse audiences. Tina earned her PhD in Biochemistry from the University of California, San Francisco and her BS degree in Cell Biology from U.C. Davis. In her spare time, she enjoys drawing science-related cartoons.