Proton pump inhibitors (PPIs), the drugs used to suppress the production of gastric acid, do not increase the risk of dementia, according to a study published in Gastroenterology, the official journal of the American Gastroenterological Association (AGA).

PPIs are widely prescribed and highly effective in treating upper gastrointestinal disorders, such as gastroesophageal reflux disease (GERD), but several recent studies have reported links between the medicines and dementia. However, the new Harvard study of 13,864 participants who completed tests on cognitive function, found no link.

"One of the most common questions gastroenterologists receive from their patients is whether PPIs are safe to use, based on the troubling headlines linking PPIs to everything from hip fracture, to dementia, to death," said study author Andrew T. Chan, M.D., an expert of the American Gastroenterological Association from Massachusetts General Hospital and Harvard Medical School, Boston.

 "Our new research should provide some reassurance to individuals who require these highly effective medications for long-term treatment."

One study, however, found that PPIs  could more than triple the risk of serious gastrointestinal infections by stomach bugs that cause food poisoning. A study published in the British Journal of Clinical Pharmacology found that PPIs suppress the production of acid that helps kill infectious bacteria, and also PPIs may change gut bacteria.

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