Causes and Risk Factors of Heartburn

Heartburn can be caused in several different ways. By understanding the most common causes of heartburn, you can make changes to your lifestyle and diet that are also part of the treatment of gastroesophageal reflux disease (GERD). Some of the mechanisms that can contribute to heartburn include direct irritation of the esophagus, weakness of the lower esophageal sphincter (LES), motility disorders of the digestive tract that result in delayed gastric emptying, and hiatal hernia.

 Often, more than one of these factors contributes to bouts of heartburn.

The Digestive System

Understanding heartburn starts with knowing how a healthy digestive system functions. Your digestive tract starts with your mouth, where food is chewed and mixed with saliva, starting the process of digestion. From here, food travels to the esophagus. This muscular tube makes tiny contractions, called peristalsis, to move the food to the stomach.

The esophagus and stomach are connected by a band of muscle fibers called the lower esophageal sphincter (LES). Normally, the LES works like a valve, opening to allow food to pass into the stomach and closing to keep food and digestive juices from flowing back into the esophagus. But if the sphincter relaxes when it shouldn't, or becomes weak, stomach acid can flow backward into the esophagus causing the burning sensation known as heartburn.

Common Causes

The underlying mechanisms that can produce heartburn can also lead to the development of GERD if your heartburn is frequent.

Esophageal Irritation

Some types of food, drink, smoking, and medications can directly irritate the lining of the esophagus and cause heartburn. In the case of medications, it may make a difference to stay upright for at least 20 to 30 minutes after taking the medication and to take the pill with a full glass of water.

Lower Esophageal Sphincter (LES) Dysfunction

If the lower esophageal sphincter is weak or loses tone, the LES will not close completely after food passes into the stomach. Stomach acid can then back up into the esophagus. Certain foods and beverages, alcohol, drugs, and nervous system factors can weaken LES and impair its function.

Motility Disorders (Slow Stomach Emptying)

In normal digestion, food is moved through the digestive tract by rhythmic contractions called peristalsis. When someone has a digestive motility disorder, these contractions are abnormal. This abnormality can be due to one of two causes—a problem within the muscle itself, or a problem with the nerves or hormones that control the muscle's contractions. Over half of people with gastrointestinal reflux disorder (GERD) have abnormal nerve or muscle function in their stomachs that could result in impaired motility.

When the muscles in the stomach do not contract normally, the stomach does not empty into the small intestine as fast as it normally would. The combination of more food left in the stomach plus increased pressure in the stomach due to the delayed emptying increases the risk for stomach acid to leak back up into the esophagus.

Hiatal Hernia

A hiatal hernia occurs when the upper part of the stomach is pushed upward into the chest through an opening in the diaphragm. This may occur due to a weakening in the diaphragm or because of increased abdominal pressure (such as with obesity.) This opening is called the esophageal hiatus or diaphragmatic hiatus. It is believed that a hiatal hernia can weaken the LES and cause reflux; however, studies have failed to prove that it is a common cause of GERD.

Pressure on the Abdomen

Excessive pressure on the abdomen can put pressure on the LES, allowing stomach acid to enter the esophagus or even the mouth.

 Pregnant women and overweight people are especially prone to heartburn for this reason.

Other Medical Conditions

Other medical conditions that may contribute to GERD include asthma and diabetes.

Genetic Factors

Studies have suggested there is an inherited risk for GERD. This could be because of inherited muscular or structural problems in the esophagus or stomach. Genetic factors may also be an important aspect in a patient's susceptibility to Barrett's esophagus, a precancerous condition caused by severe GERD.

Lifestyle Risk Factors

Some people have a naturally weak LES that is unable to withstand normal pressure from the contents of the stomach. But other factors also can contribute to this weakening and lead to heartburn episodes.

Alcohol

Alcohol relaxes the LES, allowing the reflux of stomach contents into the esophagus. It also increases the production of stomach acid and makes your esophagus more sensitive to stomach acid. Drinking alcohol can also lead to making less healthy food choices and eating foods you know can trigger your heartburn.

Smoking Tobacco

The chemicals in cigarette smoke weaken the LES as they pass from the lungs into the blood. Cigarette smoking slows the production of saliva, which is one of your body's defenses against damage to the esophagus. Smokers also produce fewer acid-neutralizing chemicals in saliva, called bicarbonates. As well, smoking stimulates the production of stomach acid and changes stomach acid by promoting the movement of bile salts from the intestine into the stomach. Digestion is slowed while you are smoking and the stomach takes longer to empty.

Foods That Often Trigger Heartburn

People differ as to which foods trigger heartburn. These are the most common:

• Coffee, tea, and other caffeinated drinks: Caffeine can relax the (LES), allowing stomach contents to reflux into the esophagus. Caffeinated beverages may also stimulate acid production.
• Chocolate: Chocolate contains concentrations of theobromine, a compound that occurs naturally in many plants such as cocoa, tea, and coffee plants. This relaxes the esophageal sphincter muscle, letting stomach acid squirt up into the esophagus.
• Fried, greasy, or fatty foods: These foods tend to slow down digestion and keep food in your stomach longer. This can result in increased pressure in the stomach, which in turn puts more pressure on a weakened LES. All of this allows reflux of what's in your stomach.
• Peppermint is often a heartburn trigger.
• Tomatoes and tomato-based products: Any foods that contain tomatoes stimulate stomach acid production.
• Spicy foods and black pepper stimulate stomach acid production.
• Citrus fruits and juices: Oranges, lemons, limes, and other citrus fruits stimulate stomach acid production.

Eating Habits

How you eat can also trigger heartburn episodes:

• Large meals: A full stomach can put extra pressure on the LES, which will increase the chance that some of this food will reflux into the esophagus.
• Eating two to three hours prior to bedtime: Lying down with a full stomach can cause stomach contents to press harder against the LES. This increases the chances of refluxed food.

Abdominal Pressure

Being overweight or obese places pressure on the abdomen that can trigger heartburn, and weight loss are recommended. Even wearing tight-fitting clothes can cause pressure in the abdomen. This forces food up against the LES and causes it to reflux into the esophagus. Tight-fitting belts and slenderizing undergarments are two common culprits. You can also feel increased symptoms when you lie down or have a full stomach.

Some people find certain types of exercise trigger heartburn. High-impact exercises that involve jumping, as well as exercises such as crunches that place pressure on the abdomen, are the most likely to be triggers.

Medications

Nearly any medication may cause heartburn, but there are clearly some drugs that are bigger culprits than others. There is more than one way in which drugs can cause heartburn and sometimes heartburn is due to a combination of different causes. You can work with your doctor to either find ways to take your medications that will decrease your heartburn symptoms or to switch to a different drug which is less likely to cause heartburn.

Medications which have been known to cause heartburn include:

• Anti-anxiety medications, such as Valium (diazepam), may not only relax your mood but your LES as well.
• Some antibiotics, such as tetracycline, can directly irritate the esophagus.
• Anticholinergics such as Compazine (prochlorperazine) and Phenergan (promethazine) can relax the LES.
• Aspirin. For some people unable to tolerate aspirin due to heartburn, enteric-coated aspirin may be an option. Never stop aspirin before talking with your doctor.
• Bisphosphonates such as Fosamax (alendronate), Actonel (resendronate), and Boniva (ibandronate) can cause heartburn by directly irritating the esophagus. If your medication is causing heartburn, there are options for preparations that are given as an injection which is less likely to cause this symptom.
• Calcium channel blockers for high blood pressure, such as Procardia (nifedipine), and Cardizem (diltiazem) can result in a weakening of the LES and also slow gastric emptying. Thankfully, there are many different classes of blood pressure medications available, and switching to another class may be helpful if your symptoms persist.
• Asthma medications such as Proventil (albuterol) and theophylline
• Chemotherapy drugs
• Corticosteroids (steroids) such as Deltasone (prednisone) and Medrol (methylprednisolone) can cause heartburn as well as other significant digestive concerns.
• Hormone replacement therapy (HRT), which is a combination of estrogen and progesterone
• Narcotics can cause heartburn by delaying gastric emptying.
• NSAIDs (nonsteroidal anti-inflammatory drugs) such as Advil (ibuprofen) and Aleve (naproxen) can increase acidity in the stomach by inhibiting prostaglandins. Options for pain control such as Tylenol (acetominophen) or even narcotic medications may be needed when NSAIDS cause significant heartburn or digestive tract upset. In some cases, making sure to take NSAIDS on a full stomach can be helpful.

• Tricyclic antidepressants, such as Tofranil (imipramine), Sinequan (doxepin), Norpramin (desipramine), and Pamelor (nortriptyline) slow gastric emptying. Many of the newer anti-depressants are less likely to cause this symptom.
• Potassium can cause heartburn by directly irritating the esophagus.
• Iron supplements can directly irritate the stomach. Some people find relief by taking these supplements with food or by using them early in the day.
• Vitamin C

Sources:

Heartburn. Mayo Clinic. http://www.mayoclinic.org/diseases-conditions/heartburn-gerd/basics/definition/CON-20019545?p=1.

GERD Lifestyle and Home Remedies. Mayo Clinic. http://www.mayoclinic.org/diseases-conditions/gerd/basics/lifestyle-home-remedies/con-20025201.

Is It Just a Little Heartburn or Something More Serious? Understanding GERD. American College of Gastroenterology. http://s3.gi.org/patients/pdfs/UnderstandGERD.pdf.

Symptoms & Causes of GER & GERD. National Institute of Diabetes Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/digestive-diseases/acid-reflux-ger-gerd-adults/symptoms-causes.