Causes of GERD
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 1: Anatomy of reflux
Gastroesophageal reflux disease is an often painful condition that occurs when the lower esophageal sphincter fails to do its job of keeping digestive juices in the stomach. When the sphincter relaxes too much, stomach acids surge up into the esophagus, sometimes causing inflammation and a painful burning sensation behind the breastbone known as heartburn.
Factors other than a malfunctioning lower esophageal sphincter contribute to acid reflux. In some people, the stomach muscles don’t contract as they should. This might lead to delayed emptying of the stomach, increasing the risk that acid will seep up into the esophagus. In others, the problem is caused by failure of coordinated movements of the muscles in the esophagus (called peristaltic contractions) to clear the esophagus of acid that has gotten into it. A reduction in the lining of the esophagus to resist damage can cause heartburn. A shortage of saliva (which has a neutralizing effect on acid) may also play a part.
Episodes of reflux often go unnoticed. But when reflux is excessive, the gastric acid irritates the esophagus and may produce pain, experienced as heartburn. Sometimes acid regurgitates as far up as the mouth. It may come up forcefully as vomit or as a “wet burp.” Most symptoms of GERD come and go, occurring after a big meal or other trigger.
Overweight people are more likely than those with healthy weights to suffer heartburn. That’s because increased pressure on the abdomen 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 during pregnancy.
GERD may be associated with other medical conditions. For example, many people with asthma also have reflux. It’s not clear, however, whether asthma is a cause or an effect. Still, asthma sometimes improves when GERD is treated.
Some people have GERD without specific anatomical malfunctions, such as a malfunctioning lower esophageal sphincter. In such cases it is called functional heartburn. Some evidence suggests that people with functional heartburn have lower pain thresholds than their healthy counterparts.
GERD can be caused by or made worse by the following:
Certain foods. Coffee, tea, cocoa, cola drinks, and other caffeine-containing products loosen the LES and stimulate gastric acid production. Mints and chocolate, often served to cap off a meal to aid in digestion, can make things worse by relaxing the LES. Fried and fatty foods contribute to heartburn. Some people say that onions and garlic give them heartburn. Others have trouble with citrus fruits or tomato products, which irritate the esophageal lining. High-fat foods may also trigger symptoms. If you notice that a particular food leads to episodes of heartburn, stay away from it.
Eating patterns. How you eat can 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 soon after eating will 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.
Smoking. Smoking can irritate the entire gastrointestinal tract. In addition, frequent sucking on a cigarette can cause you to swallow air. This increases pressure inside the stomach, which encourages reflux. Smoking sometimes also relaxes the LES.
Overweight and obesity. Being overweight or obese increases the odds of having GERD. Gaining weight increases the risk of frequent GERD symptoms—even if the person’s body mass index (a ratio of weight to height) remains in the normal range. The additional weight may increase pressure on the stomach, pushing its contents up toward the esophagus. Even modest weight gain may induce heartburn, so trying to keep your weight stable is a good idea.
Certain medications. Some prescription drugs can add to the woes of heartburn (see Table 1). 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) can irritate the stomach lining. Other drugs—such as alendronate (Fosamax), used to prevent and treat osteoporosis—can irritate the esophagus. And some antidepressants, tranquilizers, and calcium-channel blockers can contribute to reflux by relaxing the LES.
Table 1: Medications that may cause or worsen GERD
|Drug name||Sold as||Main use|
|amlodipine||generic, Norvasc||Lower blood pressure and improve coronary artery blood flow|
|nifedipine||generic, Adalat, Procardia|
|verapamil||generic, Verelan, Covera|
|Nonsteroidal anti-inflammatory drugs (NSAIDs)*|
|aspirin||generic, Bufferin, Ecotrin, others||Relieve pain and inflammation|
|ibuprofen||generic, Advil, Motrin|
|naproxen||generic, Aleve, Anaprox, Naprosyn|
|alendronate||generic, Fosamax||Build bone density|
|medroxyprogesterone acetate||generic, Prempro, Provera||Relieve symptoms of menopause; used in oral contraceptives|
|norethindrone acetate||generic, Aygestin, Micronor|
|amitriptyline||generic, Elavil, Endep||Relieve depression; occasionally used for long-term pain|
|nortriptyline||generic, Pamelor, Aventyl|
|*Each drug class includes many different medications; not all of them are listed.|
Hiatal hernia. Hiatal hernia is a common condition in which there is an opening (known as a hiatus) in the diaphragm, the muscle that separates the chest from the abdomen and helps with breathing. Part of the stomach pokes through this hole into the chest (see Figure 2). This changes the angle at which the esophagus joins the stomach and weakens the ligaments that hold these organs in proper alignment. The changes make it harder for the LES to work properly to prevent reflux. Studies indicate that a hiatal hernia, especially a large one, promotes the retention of acid above the hiatus and the seepage of acid into the esophagus.
Figure 2: 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 3 centimeters, or about 1.2 inches) often have no symptoms, others report significant heartburn. 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 hiatal hernia and reflux occur independently, there is strong evidence that the two are related.
Eosinophilic esophagitis. Eosinophilic esophagitis is a disease characterized by the presence of eosinophils, a type of white blood cell, in the wall of the esophagus. Eosinophils, which are associated with allergic reactions, stimulate inflammation. Heartburn is one symptom of eosinophilic esophagitis. A more common symptom is dysphagia, the feeling of food or pills sticking in the esophagus. Eosinophilic esophagitis often occurs in children and young adults, many of whom also have allergies or asthma. This condition often responds to treatment with a corticosteroid spray such as fluticasone (Flovent). Strong acid blockers called proton pump inhibitors (PPIs), such as omeprazole (Prilosec) or lansoprazole (Prevacid), may also help.
Each year, the economic burden of GERD in the United States is almost $10 billion.