GERD is usually caused by acid reflux happening too often, which means stomach contents keep backing up into the esophagus because the lower esophageal sphincter weakens or relaxes when it shouldn’t.

Common causes and triggers

  • A weak or overly relaxed lower esophageal sphincter.
  • A hiatal hernia, which can make reflux more likely.
  • Obesity or extra pressure on the stomach.
  • Pregnancy.
  • Smoking.
  • Certain medicines, including some NSAIDs, calcium channel blockers, sedatives, and some asthma or antidepressant medicines.
  • Large meals, late-night eating, fatty or fried foods, alcohol, coffee, chocolate, mint, and other foods that can worsen symptoms.

What is happening

Normally, the valve between the esophagus and stomach closes after food passes through. When that valve is weak, loosened, or working at the wrong time, acid can flow upward and irritate the esophagus, leading to heartburn and other GERD symptoms.

When to get checked

If reflux happens often, wakes you up, causes trouble swallowing, or comes with chest pain, it’s worth getting medical advice because repeated reflux can injure the esophagus.

TL;DR: GERD is mainly caused by a weak or poorly functioning valve between the stomach and esophagus, often made worse by hiatal hernia, weight, pregnancy, smoking, certain medicines, and trigger foods.