New research from Stanford University has found a surprising link between proton-pump inhibitors (PPIs) and an increased risk of heart attacks. PPIs are the most commonly prescribed heartburn medicines (1 in 14 people take them each year) that also include over-the-counter brands like Nexium, Prevacid, and Prilosec. (Check out 9 foods that soothe heartburn naturally.) The study, published in the journal PLOS ONE, relied on health record data for almost three million people. Even after those taking clopidogrel (a blood thinner that increases risk of heart trouble in combination with a PPI) were filtered out of the study, a 20% increase in cardiovascular risk still remained. Those taking different heartburn drugs called H2 blockers (like Pepcid and Zantac) seemed to have a lower risk of heart attacks. At the same time, researchers looked at an ongoing Stanford study focused on 1,500 people with cardiac problems, which showed that those on PPIs more than doubled their risk of having a major cardiac event. And yet another study from Taiwan discovered that one additional heart attack occurred for every 4,357 people taking PPIs for two weeks. MORE: The Unbelievable Reason You’re Short On Vitamin D All this is alarming to say the least. But according to Nigam Shah, PhD, an assistant professor at Stanford and the study’s lead author, even though “the evidence indicates a cause for concern about cardiovascular risk,” the study stops short of concluding that PPIs really do lead to, or cause, heart attacks. And there’s no proof yet on whether the risk increases for people who take higher doses or who take them for an extended period of time. Nor does it make clear whether there’s a risk because PPIs hinder the production of nitric oxide, a substance in blood vessel linings that regulate blood flow, as shown by other Stanford research. (Looking to improve your digestive health naturally? Check out The Good Gut Diet for natural, effective solutions.) MORE: 6 Surprising Causes Of Inflammation—And What You Can Do About It “Many people don’t realize that when these medications were first approved years ago, there were very specific recommendations about taking them for only a short time period,” says Erica C. Jones, MD, director of Weill Cornell Medical College’s HeartHealth Program in New York. “Now, most patients take them chronically.” If you are taking a PPI, talk to your doctor before you stop; she might be able to recommend alternative treatments. And remember that adopting a healthy lifestyle is equally important in reducing acid and heartburn. “The problem is that these medications work so well in alleviating symptoms of acid reflux, most patients continue taking them long-term instead of taking the steps necessary to avoid it,” says Mildred Frantz, MD, a family medicine physician based in Eatontown, New Jersey.  Next time you reach for a second cup of coffee or crave chili fries, consider that you might be better off fighting heart burn—and avoiding a raised risk of heart trouble—the natural way.