Acid reflux happens when stomach acid flows backward into the esophagus, the tube connecting your mouth to your stomach. It affects roughly 800 million people worldwide, making it one of the most common digestive conditions on the planet. Most people experience it occasionally after a heavy meal, but when it happens regularly, it becomes a chronic condition known as gastroesophageal reflux disease, or GERD, which about 7% of Americans deal with daily.
How Acid Reflux Works
At the bottom of your esophagus sits a ring of muscle that acts like a one-way valve. It opens to let food pass into your stomach, then closes to keep digestive acid where it belongs. Acid reflux occurs when this valve relaxes at the wrong time, a phenomenon called transient lower esophageal sphincter relaxation. This is the primary mechanism behind reflux in most people, and it happens in healthy individuals too. It’s triggered by the stomach stretching, typically after eating, and is meant to release excess gas. The problem arises when acid hitches a ride with that gas.
A common assumption is that people with reflux simply have a weak valve. That’s not usually the case. In the majority of people with mild to moderate reflux, valve pressure is completely normal. The issue is how often the valve relaxes inappropriately and how well the esophagus clears acid once it arrives. A hiatal hernia, where part of the stomach pushes up through the diaphragm, can change the valve’s position and prevent it from closing completely. This makes reflux more frequent and harder to control.
Common and Surprising Symptoms
The two hallmark symptoms are heartburn (a burning sensation behind the breastbone) and regurgitation (the taste of acid or undigested food in the back of the throat). Up to 40% of the U.S. population experiences these monthly. But acid reflux can also show up in ways you might not expect.
Reflux-related chest pain can feel squeezing or burning, sit behind the breastbone, and radiate to the back, neck, jaw, or arms. It mimics heart-related chest pain closely enough that many people end up in the emergency room before discovering the cause is digestive. Other less obvious symptoms include a chronic cough, hoarseness, frequent throat clearing, a sore or burning throat, and difficulty swallowing. Some people develop a persistent feeling of a lump in the throat, called globus sensation, which tends to be more noticeable between meals and disappears at night. Reflux accounts for 25% to 50% of globus cases. In some people, acid reaching the airways can worsen or even trigger asthma symptoms.
What Increases Your Risk
Carrying extra weight around the abdomen is one of the strongest risk factors. Abdominal fat physically increases pressure inside the abdominal cavity, which pushes stomach contents upward toward the esophagus. Studies using pressure measurements in the stomach have confirmed that people with obesity have significantly higher intra-abdominal pressures than those without. That sustained pressure also promotes the development of hiatal hernias, which further weaken the barrier against reflux.
Pregnancy raises risk through a similar mechanism: the growing uterus increases abdominal pressure while hormonal changes relax smooth muscle, including the esophageal valve. Other factors include smoking, eating large meals close to bedtime, and a family history of reflux disease.
Foods and Drinks That Trigger Reflux
Certain foods directly reduce the pressure of the esophageal valve, making it easier for acid to escape. High-fat meals, chocolate, alcohol, and carbonated beverages all lower valve pressure and increase the time acid spends in contact with the esophagus. Mint and caffeinated drinks have a similar relaxing effect on the valve. Spicy foods, citrus fruits, tomatoes, onions, and garlic don’t necessarily weaken the valve but can irritate an already-inflamed esophagus, making symptoms worse.
Swapping to low-fat or lean protein sources like skinless poultry, fish, or tofu can help minimize symptoms, since fat is one of the most reliable triggers. Eating smaller meals also reduces the stomach stretching that prompts the valve to relax.
What Happens if Reflux Goes Untreated
Occasional heartburn isn’t dangerous. Chronic, uncontrolled reflux is a different story. Repeated acid exposure inflames the esophageal lining, a condition called esophagitis. Over time, the body may respond to this persistent damage by replacing the normal tissue of the esophagus with a different type of tissue that more closely resembles the intestinal lining. This change is called Barrett’s esophagus.
Barrett’s esophagus matters because it’s a precancerous condition. The replacement tissue can develop increasingly abnormal cells, progressing through stages of low-grade and then high-grade changes before potentially becoming esophageal cancer. This progression happens in steps and usually takes years, which is why people with long-standing, severe reflux are monitored with periodic endoscopy. Not everyone with Barrett’s develops cancer, but the condition does elevate the risk substantially.
How Acid Reflux Is Diagnosed
Most people with typical heartburn and regurgitation are initially treated based on symptoms alone, often with a trial of acid-reducing medication. If symptoms don’t improve, or if there’s any uncertainty about the diagnosis, testing becomes important.
The gold standard is ambulatory pH monitoring, a 24-hour test that measures acid levels in the esophagus. A small sensor is placed about 5 centimeters above the esophageal valve, either on a thin wire passed through the nose or as a tiny wireless capsule attached to the esophageal wall. The test identifies reflux episodes by detecting when esophageal pH drops below 4, the threshold indicating stomach acid is present.
Endoscopy, where a thin camera is passed into the esophagus and stomach, is reserved for people with alarm symptoms: difficulty swallowing, painful swallowing, gastrointestinal bleeding, unexplained weight loss, loss of appetite, or persistent vomiting. These can signal complications like strictures, Barrett’s esophagus, or other conditions that need direct visualization.
Medication Options
Two main categories of medication reduce stomach acid, and they work differently. The milder option blocks one of the chemical signals that tells your stomach to produce acid, resulting in a moderate and relatively short-lived reduction in acid output. The stronger option permanently disables the acid-producing pumps in stomach cells, creating a more powerful and longer-lasting suppression. New pumps are constantly being made, so the effect isn’t truly permanent, but it’s substantially stronger than the first category.
For occasional reflux, over-the-counter antacids that neutralize existing acid provide the fastest relief. The milder acid-reducers work well for infrequent symptoms. For persistent or daily reflux, the stronger pump-disabling medications are typically more effective. Your doctor can help determine which approach fits your pattern of symptoms.
Lifestyle Changes That Help
Sleep position makes a meaningful difference for nighttime reflux. Sleeping on your left side reduces both the amount of acid that enters the esophagus and the time it takes to clear acid away, compared to sleeping on your right side or on your back. The 2022 guidelines from the American College of Gastroenterologists specifically recommend left-side sleeping as a management strategy. Combining this with elevating the head of your bed (using a wedge pillow or bed risers, not just extra pillows) can further reduce overnight acid exposure.
Other practical changes include not lying down for two to three hours after eating, eating smaller and more frequent meals rather than large ones, and avoiding your personal trigger foods. Losing weight, if you carry excess abdominal fat, addresses one of the root mechanical causes of reflux rather than just managing symptoms. Even modest weight loss can reduce the abdominal pressure that pushes acid upward.