Causes Of Reflux - Gastroesophageal Reflux Disease: Digestive Disorders

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Causes of reflux

GERD is a digestive disorder affecting the lower or reflux esophageal sphincter (LES), the muscle connecting the esophagus and stomach. The LES is a high-pressure zone that acts as a barrier to protect the esophagus against the backflow of gastric acid from the stomach.

Normally, the LES works something like a dam, opening to allow food to pass into the stomach and closing to keep food and acidic stomach juices from flowing back into the esophagus. Gastroesophageal reflux occurs when the LES relaxes when it shouldn't or becomes weak, allowing contents of the stomach to flow up into the esophagus (see Figure 4). Scientists aren't sure exactly why this happens. The LES is a complex segment of smooth muscle under the control of nerves and various hormones. As a result, dietary substances, drugs, and nervous system factors can impair its function.

Figure 4: Reflux Also known as gastroesophageal reflux disease (GERD), this often painful condition occurs when the lower esophageal sphincter fails to do its job of keeping digestive juices in the stomach. When the sphincter relaxes too much, irritating stomach acids surge up into the esophagus, sometimes causing inflammation and a painful burning sensation behind the breastbone known as heartburn.

Factors other than malfunctions of the LES contribute to reflux. In one study, about half of reflux patients exhibited abnormal nerve or muscle function in the stomach, which impaired motility — that is, the ability of the stomach muscles to contract in a normal fashion. This might delay the emptying of the stomach, increasing the risk that acid will reflux back into the esophagus. A failure of peristaltic contractions to clear the esophagus of acid that has refluxed, a lessening of the esophageal lining's ability to resist damage, or a shortage of saliva (which has a neutralizing effect on acid) may play a part as well.

Episodes of reflux often go unnoticed, but when reflux is excessive, the gastric acid irritates the gullet and may produce pain, experienced as heartburn. Sometimes acid regurgitates as far as the mouth and may come up forcefully as vomit or as a "wet burp." Most symptoms of GERD are transient and only occur, for example, after a big meal or when a person bends over or lies down.

Overweight people and pregnant women may suffer more heartburn episodes because increased abdominal pressure contributes to reflux. Pregnant women are also more prone to heartburn because the LES relaxes in response to the high levels of the hormone progesterone that occur with pregnancy. Generally, though, GERD is uncommon in people under age 40.

Other medical conditions can also contribute to GERD. About half of asthma patients also have reflux. It's not clear, however, whether asthma is a cause or effect (see "Asthma and reflux"). Still, asthma may improve when GERD is treated. Other illnesses that may contribute to reflux include diabetes, peptic ulcers, and some types of cancer.

Foods that cause reflux. Diet can contribute to LES dysfunction. For example, alcohol can irritate the esophageal lining and loosen the LES, as can coffee and other caffeine-containing products. Coffee, tea, cocoa, and cola drinks are all powerful stimulants of gastric acid production. Mints and chocolate, often served to cap off a meal to aid in digestion, can actually make things worse. Both relax the LES and can induce heartburn, as can fried and fatty foods. Some people say that onions and garlic give them heartburn. Others have trouble with citrus fruits or tomato products. If you notice that a particular food leads to episodes of heartburn, by all means stay away from it.

Lifestyle causes. How you eat can also be as important as what you eat. Skipping breakfast or lunch and then consuming a huge meal at day's end can increase gastric pressure and the possibility of reflux. Lying down right after eating will only make the problem worse. It is best to wait three hours after eating before going to bed. And stay away from late-night snacks, too. Even a modest weight gain may induce heartburn, so a low-fat diet is a good idea for more than just one reason.

Smoking. Smoking can irritate the entire GI tract. Frequent sucking on a cigarette causes air to be swallowed, increasing stomach pressure and encouraging reflux. Smoking sometimes also relaxes the LES muscle.

Medications that cause heartburn. Some prescription drugs can exacerbate heartburn. Oral contraceptives or postmenopausal hormone preparations containing progesterone are known culprits. Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn) may also pose problems. A group of prescription NSAIDs known as COX-2 inhibitors are widely used to relieve pain because they are designed to be easier on the stomach than standard NSAIDs. But these drugs have come under scrutiny. Two COX-2 inhibitors were voluntarily removed from the market because of an increased risk for heart attack and stroke; medical and government review of these and similar drugs continues. Corticosteroids, used to treat a variety of medical conditions, are also known to cause heartburn. Other drugs — such as alendronate (Fosamax), used to prevent and treat osteoporosis — can irritate the esophagus. And some antidepressants, tranquilizers, and calcium-channel blockers, as well as the asthma medication theophylline, can contribute to reflux by relaxing the LES (see Table 1).

The hiatal hernia connection. Hiatal hernia is a common condition in which there is an opening, or hiatus, in the diaphragm, the muscle that separates the chest from the abdomen and helps with breathing. This hiatus permits part of the stomach to protrude into the chest (see Figure 5). The resulting protrusion changes the angle at which the esophagus joins the stomach, weakening the ligaments that hold these organs in proper alignment and impairing the LES's ability to prevent reflux. Studies indicate that a hiatal hernia, particularly if large, promotes retention of acid above the hiatus and reflux of acid into the esophagus, causing irritation and pain.

Figure 5: Hiatal hernia One possible cause of heartburn is a common condition called hiatal hernia, in which a portion of the stomach protrudes through the opening in a weak diaphragm, the band of muscle that separates the chest from the abdomen.

While people with small hiatal hernias (less than three centimeters, or about 1.2 inches) often have no symptoms, others report significant heartburn discomfort. Almost all people with large hiatal hernias have reflux. And hiatal hernias are almost always present in people with GERD who have moderate or severe esophagitis (inflammation of the esophagus). While the hiatal hernias and reflux occur independently, there is strong evidence that the two are related.

Last updated:	August 21, 2007