NASHVILLE, April 20 (UPI) -- Gerbils infected with H. pylori -- the ulcer-causing bacterium -- given a high-salt diet were linked to increased risk of gastric cancer, U.S. researchers say.
Timothy L. Cover and colleagues of Vanderbilt University in Nashville infected Mongolian gerbils with H. pylori. One set received a regular diet; the other, a high-salt diet. At the end of the experiment the researchers analyzed the animals' stomach tissues.
The study, published in the journal Infection and Immunity, found every animal on the high-salt diet developed cancer, compared with just 58 percent of those on the regular diet.
However, the researchers said it appeared development of gastric cancer required the presence of a particular bacterial oncoprotein, known as CagA, which is produced by H. pylori.
Gastric cancer did not develop in animals on the high salt diet that were infected with a mutant H. pylori which did not produce CagA.
The investigators also detected significantly higher levels of gastric inflammation in H. pylori-infected gerbils on a high-salt diet than in those on a regular diet, a finding relevant to many types of cancer, Cover said.
At least 50 percent of humans are infected with H. pylori, at least 90 percent of them without symptoms, Cover said.
The study is scheduled to be published in the June issue of Infection and Immunity.