About 70 per cent of chronic liver disease patients take medication to prevent the symptoms of heartburn and acid reflux.
But, suppressing stomach acid stops gut bacteria from killing unwanted micro-organisms in the body.
Those micro-organisms could be promoting liver injury, and three types of chronic liver disease, researchers have warned.
The acid reflux drugs – known as Proton Pump Inhibitors (PPIs) – block the enzymes that make stomach acid. Common PPIs include the brands Prilosec, Nexium and Prevacid.
Senior author of the research, Bernd Schnabl, from the University of California, said: “Our stomachs produce gastric acid to kill ingested microbes, and taking a medication to suppress gastric acid secretion can change the composition of the gut microbiome.
“Since we found previously that the gut microbiome – the communities of bacteria and other microbes living there – can influence liver disease risk, we wondered what effect gastric acid suppression might have on the progression of chronic liver disease.
“We found that the absence of gastric acid promotes growth of bacteria in the intestines and translocation to the liver, where they exacerbate inflammation and worsen chronic liver disease.”
The researchers used mice trials to find how the drugs impact liver disease.
Mice were given PPIs, and then their poo was analysed to find which bacteria were still in their stomach.
They found the mice had more bacteria that promotes liver disease.
The changes also meant the mice had more inflamed livers, and three types of liver disease was progressing in them.
The scientists also tested the link between the drugs and liver disease in humans that abuse alcohol.
4,830 patients that had a history of chronic alcohol abuse were analysed, including more than 1,000 patients actively taking heartburn medication.
Similarly to mice, they found more of the liver disease-causing bacteria in the humans’ stool.
Liver disease development in patients that chronically abused alcohol was more than eight per cent higher in those that used PPIs.
The finding could lead to a new therapy who focuses on reducing the amount of bad bacteria in the stomach, the researchers said.