Acid reflux is the backward flow of stomach acid into the esophagus, the tube connecting your mouth to your stomach. It affects roughly 825 million people worldwide, and about 45 million in the United States alone. Most people experience it occasionally after a heavy meal, but when it becomes frequent or causes lasting damage, it crosses into a chronic condition called gastroesophageal reflux disease, or GERD.
How Acid Reflux Happens
At the bottom of your esophagus sits a ring of muscle called the lower esophageal sphincter. It opens to let food drop into your stomach, then closes to keep stomach acid where it belongs. Acid reflux occurs when this muscle relaxes at the wrong time or doesn’t close tightly enough, allowing acidic stomach contents to wash back upward. The esophagus has a near-neutral environment (around pH 7.0), so even brief exposure to stomach acid, which is far more acidic, irritates the lining and produces that familiar burning sensation.
Several things can weaken or relax this sphincter. High-fat, fried, and spicy foods are the most common dietary triggers because they cause the sphincter to relax and slow digestion, letting food sit in the stomach longer. Other well-known triggers include tomato-based sauces, citrus fruits, chocolate, peppermint, and carbonated drinks. Eating large meals, lying down soon after eating, smoking, and carrying excess weight around the midsection all increase pressure on the stomach and push acid upward.
Acid Reflux During Pregnancy
Pregnancy is one of the most common triggers, and for two distinct reasons. First, rising levels of the hormone progesterone relax the lower esophageal sphincter, making it easier for acid to escape. Progesterone also slows digestion overall, so food lingers in the stomach longer and increases the chance of reflux. Second, as the uterus expands through the second and third trimesters, it physically crowds the stomach and forces acid upward into the esophagus. These two factors together make heartburn one of the most frequently reported pregnancy symptoms.
Symptoms Beyond Heartburn
The classic symptom is a burning feeling behind the breastbone that worsens after eating or when lying down. But acid reflux can show up in less obvious ways, especially when acid travels higher than the esophagus.
If acid reaches the throat, it can cause a persistent sore throat, a sensation of a lump in the throat, or difficulty swallowing. Some people develop a condition called laryngopharyngeal reflux, where acid sneaks into the throat during sleep, causing hoarseness, vocal cord swelling, and even small growths on the vocal cords.
Acid reflux can also mimic respiratory problems. When tiny acid particles enter the airways, they trigger the muscles there to contract, producing chronic coughing, wheezing, and shortness of breath that looks a lot like asthma. People sometimes chase a respiratory diagnosis for months before discovering that reflux is the underlying cause.
When Reflux Becomes GERD
Everyone has occasional acid reflux. It becomes GERD when it causes bothersome symptoms on a regular basis or leads to long-term complications. There’s no single “two episodes per week” cutoff that applies to everyone. Clinically, doctors look at how much time your esophagus spends exposed to acid: less than 4% of the time is considered normal, while 6% or more is diagnostic for GERD.
If an upper endoscopy shows visible damage to the esophageal lining (graded on a scale from A through D), moderate to severe grades confirm the diagnosis even without further testing. But many people with GERD have no visible damage at all, so the absence of erosion doesn’t rule it out.
Long-Term Complications
Chronic, untreated acid exposure can cause the cells lining the lower esophagus to change over time, a condition called Barrett’s esophagus. About 3% of people with GERD develop it. Barrett’s esophagus itself is not cancer, but it raises the risk. Without any precancerous changes, the annual risk of progressing to esophageal cancer is between 0.1% and 0.33%, which is quite low. That risk climbs to about 0.5% per year with early precancerous changes and up to 7% per year with advanced precancerous changes.
Other complications of ongoing reflux include esophageal strictures (narrowing from scar tissue that makes swallowing difficult), esophageal ulcers, and chronic inflammation. Dental erosion is another underrecognized consequence: repeated acid exposure slowly dissolves tooth enamel, particularly on the back surfaces of the upper teeth.
Lifestyle Changes That Help
For mild or occasional reflux, lifestyle adjustments are often enough. Avoiding known trigger foods, especially fried foods, fatty meats, cheese, tomato sauces, chocolate, and peppermint, reduces episodes significantly. Eating smaller meals and waiting at least two to three hours before lying down gives the stomach time to empty.
Sleep position matters more than most people realize. Sleeping on your left side reduces acid exposure because of the way the stomach and esophagus are positioned: gravity keeps acid pooled away from the opening to the esophagus. Sleeping on the right side does the opposite and tends to worsen nighttime symptoms. Elevating the head of your bed by six to eight inches (using a wedge pillow or bed risers, not just extra pillows) also helps prevent acid from traveling upward overnight.
Losing weight, if you carry extra weight around the abdomen, reduces the mechanical pressure pushing acid into the esophagus. Quitting smoking helps too, since nicotine relaxes the lower esophageal sphincter.
Medication Options
When lifestyle changes aren’t enough, two main categories of acid-reducing medications are available over the counter and by prescription.
- H2 blockers work by blocking a specific signal that tells your stomach cells to produce acid. They kick in within about an hour and provide relief lasting four to ten hours. They’re a good option for predictable, occasional symptoms, like taking one before a meal you know will cause trouble.
- Proton pump inhibitors (PPIs) are more powerful acid suppressors. They take longer to reach full effect, sometimes one to four days, but they last much longer and are better suited for daily management of frequent reflux or confirmed GERD.
Antacids (the chewable tablets and liquids) neutralize acid that’s already in the stomach and provide the fastest relief, but their effects are short-lived. They’re useful for breakthrough symptoms but aren’t designed for regular control.
For people who don’t respond to medication or who want to stop long-term drug use, surgical procedures can tighten the lower esophageal sphincter. These are typically reserved for severe or complicated cases.