Millions of Americans with occasional heartburn turn to medications such as omeprazole (Prilosec), esomeprazole (Nexium) and lansoprazole (Prevacid) to help reduce stomach acid, but new research may have folks thinking twice about the possible side effects—and considering safer natural alternatives.

Last month’s Health Report featured an interview with Douglas Corley, a board-certified gastroenterologist and research scientist with Kaiser Permanente in California. Dr. Corley discussed the results of a recent study he and his colleagues conducted, which showed that people taking a class of acid-suppressing medications known as PPIs (proton pump inhibitors) for heartburn and reflux may be at a higher risk for vitamin B12 deficiency.

Kaiser Permanente provides health care coverage to more than 3 million Americans annually, and after reviewing its member records Corley and his team found that those using PPIs were about 65% percent more likely to develop vitamin B12 deficiency, as opposed to a 25% risk increase for those taking another class of heartburn drugs called H2 blockers (e.g. Zantac).

According to Dr. Corley, “Vitamin B12 deficiency can cause nerve damage, so it can cause numbness or tingling in the hands or the feet. In severe cases it can cause dementia and nerve damage to the brain. And it can also cause anemia.” While he emphasized this was just a single study and more research is needed, Dr. Corley advised people to be cautious about taking certain medications and to consider getting checked for vitamin B12 deficiency if taking PPIs.