What causes gastroesophageal reflux disease (GERD) or heartburn?

From the Guidelines

Gastroesophageal reflux disease (GERD) or heartburn is primarily caused by acid reflux, which occurs when stomach acid flows back up into the esophagus, and can be triggered by certain foods, beverages, and lifestyle factors, as well as underlying medical conditions. The most recent and highest quality study, 1, suggests that weight loss and bed elevation are effective lifestyle interventions for GERD, and that weight reduction in those who are overweight or obese can improve symptom control. Common triggers for heartburn include:

• Certain foods and beverages such as spicy foods, citrus, tomatoes, chocolate, coffee, alcohol, and fatty or fried items
• Lifestyle factors such as overeating, eating too quickly, lying down soon after meals, being overweight, smoking, and wearing tight clothing around the waist
• Medical conditions like hiatal hernia, pregnancy, and gastroesophageal reflux disease (GERD)
• Some medications, including certain pain relievers, blood pressure medications, and some antibiotics, may worsen symptoms
• Stress and anxiety can increase acid production and exacerbate heartburn Understanding these causes helps in managing symptoms through dietary changes, weight management, elevating the head while sleeping, and avoiding eating close to bedtime. As stated in 1, lifestyle modifications recommended for GERD fall into three categories: avoidance of foods that may precipitate reflux, avoidance of acidic foods that may precipitate heartburn, and adoption of behaviors that may reduce esophageal acid exposure. However, the study 1 provides more recent and higher quality evidence, and suggests that weight loss and bed elevation are the most effective lifestyle interventions for GERD. Therefore, the most effective way to manage GERD symptoms is through a combination of weight loss, bed elevation, and avoidance of trigger foods and beverages, as supported by the highest quality evidence 1.

From the Research

Causes of Gastroesophageal Reflux Disease (GERD)

• GERD is a multi-factorial disease, and its etiology is believed to be principally a consequence of altered motility states in the esophagus and stomach 2
• The reflux of gastric contents into the esophagus due to a decline in esophageal clearance and anti-reflux barrier mechanisms can cause GERD 3
• Acid-producing cells in the upper aerodigestive tract and acid-producing bacteria located within the upper gastrointestinal tract and oral cavity may also contribute to the onset of GERD 4
• Weakly acidic reflux and/or non-acid-related events can also play a significant role in the generation of heartburn, a typical symptom of GERD 5

Pathophysiology of GERD

• Mucosal injury in GERD is caused by a combination of gastric juice directly damaging the esophageal mucosa and the immune and inflammatory mechanism in which inflammatory cytokines released from the esophageal mucosal epithelium cause neutrophil migration, triggering inflammation 3
• Contact with and damage to the oesophageal epithelium by acidic refluxate can cause micro or macroscopic defects leading to the symptom of heartburn 6
• Dilated intercellular spaces within oesophageal stratified squamous epithelium can reflect damage to the intercellular junctions and enable levels of acidity to initiate pathological responses within oesophageal nociceptors, giving rise to the symptom of heartburn 6

Factors Contributing to GERD

• Altered motility states in the esophagus and stomach can contribute to GERD 2
• Decline in esophageal clearance and anti-reflux barrier mechanisms can cause GERD 3
• Acid-producing cells and bacteria in the upper aerodigestive tract can contribute to the onset of GERD 4
• Non-acid-related events and weakly acidic reflux can play a significant role in the generation of heartburn 5