Under normal circumstances, your LES is only supposed to open and close “the gate” when you drink liquids, eat, or burp. But the increased abdominal pressure in your stomach, like a balloon filled up with air, allows your LES to open and close when it’s not supposed to—which is how gastric acid is able to reach your esophagus in the first place. This is what creates the burning sensation of acid reflux, because your esophagus and the rest of your upper GI tract isn’t protected from strong acidity the way your stomach lining is.
Low stomach acid as a cause of acid reflux can also explain why many people feel relief from GERD symptoms when they supplement with hydrochloric acid (stomach acid) (3). If acid reflux was caused by excess stomach acid production, supplementing with HCl would only make the condition worse. It’s also worth noting that our stomach acid production declines as we get older, which may explain why senior citizens are the most prevalent age group to suffer from acid reflux (4).
Before we go any further, let’s take a look at the biggest cause of low stomach acid—and therefore, symptoms of acid reflux—your diet.