Popular stomach acid pills taken to fight indigestion could more than triple the risk of serious gastrointestinal infections, stomach bugs that cause food poisoning. A study published in the British Journal of Clinical Pharmacology found that medicines called proton pump inhibitors (PPIs) that suppress the production of acid increase the risk of stomach bugs that cause food poisoning.

Compared with people who didn't take PPIs, researchers found that when individuals who used the medications were compared with individuals who didn't, those who did had 1.7-times increased risk of C. difficile and 3.7-times increased risk of Campylobacter, two bacteria that cause intestinal infections.

Among hospitalized patients, those using the medications had 1.4-times and 4.5-times increased risks, respectively.

"The reason for the apparent rise in food poisoning risk may be that when you metabolize these pills, the bacteria in your gut may be changed," wrote researcher Li Wei.

"You may have an increased susceptibility to infection because your stomach acid acts as a barrier. All these bacteria have to be balanced between good and bad bacteria in a certain way to keep people healthy.

"We are not saying people should not take these common drugs, but they must know there might be an increased risk and take extra care in terms of food hygiene," Wei concluded.

"Users of these medications should be particularly vigilant about food hygiene as the removal of stomach acid makes them more easily infected with agents such as Campylobacter, which is commonly found on poultry," said senior author Thomas MacDonald.

Examples of PPIs include Prilosec, Prevacid, and Nexium.

The drugs were thought to be relatively harmless when they were first introduced almost 30 years ago (Prilosec hit the market in 1988, Prevacid in 1991, and Nexium in 2001), but studies have linked them to a number of side effects including an increased risk of bone fracture, diarrhea, and reduced absorption of nutrients.

In addition, a 2015 study found that people who took PPIs raised their risk of heart attack by almost 20 percent.