Occasional acid reflux is not dangerous. Most people experience it from time to time, and it resolves on its own without causing any lasting harm. Chronic acid reflux, however, is a different story. When stomach acid repeatedly washes back into the esophagus over months or years, it can cause real tissue damage, trigger complications beyond the digestive tract, and in rare cases set the stage for esophageal cancer.
What Happens Inside Your Esophagus Over Time
Your esophagus is lined with soft tissue that was never designed to handle stomach acid. A ring of muscle at the bottom of your esophagus, called the lower esophageal sphincter, normally keeps acid where it belongs. When that muscle relaxes too often or doesn’t close tightly enough, acid creeps upward. An occasional episode causes temporary irritation. Repeated exposure causes a cascade of increasingly serious damage.
The first stage is erosive esophagitis, where the acid literally eats into the lining and creates visible breaks in the tissue. Doctors grade this damage on a scale from A (small, isolated breaks less than 5 mm long) to D (breaks covering 75% or more of the esophageal circumference). If erosions deepen, they become ulcers. Among patients with esophageal ulcers, about 34% develop bleeding and roughly 12.5% develop strictures, which are bands of scar tissue that narrow the esophagus and make swallowing progressively difficult.
Strictures develop in about 10% of patients with untreated erosive esophagitis. They’re more common in older adults and form when chronic inflammation triggers the body to lay down collagen and scar tissue as a repair response. This narrowing can make it hard to swallow solid food, and sometimes even liquids.
Barrett’s Esophagus and Cancer Risk
The most serious long-term consequence of chronic acid reflux is a condition called Barrett’s esophagus. When the esophageal lining endures years of acid damage, the body sometimes replaces its normal cells with a different type of cell, one that looks more like intestinal tissue. This process, called intestinal metaplasia, is the body’s attempt to protect itself. But these replacement cells can become abnormal over time and eventually turn cancerous.
The good news: the actual cancer risk is low. Among people with Barrett’s esophagus, the annual rate of developing esophageal adenocarcinoma ranges from about 0.12% to 0.6%, depending on the study. Two large population-based studies found the absolute annual risk was only 0.12% to 0.14%. That’s roughly 1 in 700 to 1 in 800 per year. Still, the risk is real, and esophageal adenocarcinoma is an aggressive cancer with poor survival rates when caught late. That’s why people diagnosed with Barrett’s esophagus undergo regular endoscopic surveillance to catch precancerous changes early.
Damage Beyond the Esophagus
Acid reflux doesn’t always stay in the esophagus. When acid travels high enough to reach the throat, voice box, or airways, it causes a set of problems collectively known as laryngopharyngeal reflux (LPR). This can happen through two routes: acid directly contacting and irritating tissues in the throat and lungs, or acid in the lower esophagus triggering nerve reflexes that cause airway tightening.
The respiratory effects can be significant. Chronic cough, worsening asthma, and laryngitis are all established consequences of reflux reaching the upper airway. Nocturnal reflux is particularly problematic because lying flat makes aspiration more likely. Research has linked nighttime reflux to coughing episodes, airway spasms, and even obstructive sleep apnea. When acid reaches the trachea and bronchial tubes through aspiration, it can provoke severe respiratory symptoms.
Your teeth are also at risk. Stomach acid has a pH of about 1 to 2, which is far more acidic than the pH of 5.5 at which tooth enamel starts dissolving. In people with frequent reflux, the regurgitated acid makes direct contact with teeth and gradually strips away enamel. Studies have found dental erosion in roughly 45% to 65% of people with significant reflux symptoms, compared to about 37% in people without reflux. Unlike cavities, this erosion happens without bacteria. It’s pure chemical dissolution.
When Chest Pain Might Not Be Reflux
One of the genuinely dangerous aspects of acid reflux is how closely it mimics a heart attack. Heartburn, angina, and heart attack can feel so similar that even experienced doctors sometimes can’t distinguish them based on symptoms alone. This similarity cuts both ways: people having a heart attack sometimes dismiss it as heartburn, and people with severe reflux sometimes rush to the emergency room fearing the worst.
Heart attack symptoms to watch for include pressure, tightness, or squeezing pain in the chest that may spread to your neck, jaw, or back. Cold sweats, sudden dizziness, fatigue, and shortness of breath are also red flags. Women are more likely than men to experience jaw pain, back pain, nausea, and shortness of breath rather than classic chest crushing. If you have persistent chest pain and aren’t certain it’s heartburn, treat it as a potential cardiac event. The cost of being wrong about reflux is embarrassment; the cost of being wrong about a heart attack is far higher.
Long-Term Medication Trade-offs
Proton pump inhibitors (PPIs), the most commonly prescribed medications for chronic reflux, are highly effective at suppressing acid production. Short-term use is generally well-tolerated. But because chronic reflux often requires years of treatment, the cumulative effects of long-term PPI use have drawn increasing scrutiny.
A large meta-analysis of over 6.8 million participants found that PPI use was associated with a 72% increased risk of chronic kidney disease compared to non-use. The proposed mechanism involves direct toxic effects on kidney cells and changes in gut bacteria. Bone fracture risk also rises with prolonged use: a review of 24 studies covering more than 2 million people found a 20% overall increase in hip fracture risk, climbing to 24% with long-term use. This is likely tied to impaired calcium absorption in a less acidic stomach.
Cognitive effects have also surfaced in the research. One study of nearly 74,000 elderly individuals found regular PPI users had a 44% higher risk of developing dementia. Another found that cumulative use exceeding 4.4 years was associated with a 33% increased risk, though shorter durations showed no significant effect. Long-term PPI use has also been linked to vitamin B12 deficiency, with an 83% increased risk in one study, since stomach acid plays a key role in absorbing this nutrient.
These findings don’t mean PPIs are unsafe for everyone. They do mean that people using them for years should have ongoing conversations with their doctors about whether the benefits still outweigh the risks, and whether lifestyle changes or alternative approaches might reduce the need for continuous medication.
Warning Signs That Need Attention
Most acid reflux is a nuisance, not an emergency. But certain symptoms signal that damage may be progressing and warrant prompt evaluation. Difficulty swallowing, especially if it’s getting worse over time, can indicate a stricture or, less commonly, a tumor. Unintentional weight loss alongside reflux symptoms raises similar concerns. Vomiting blood or finding blood in your stool suggests ulceration or bleeding in the esophagus. Persistent symptoms that don’t respond to over-the-counter antacids, or reflux that has been present for many years without medical evaluation, also justify a closer look with an endoscopy to check for Barrett’s esophagus or other structural changes.