May 13, 2013

Salt revs stomach bug’s cancer impact

A high-salt diet worsens the carcinogenic effects of Helicobacter pylori, a bacterium that colonizes the stomachs of half of the world’s population.


Infection with the stomach-dwelling bacterium Helicobacter pylori – particularly strains expressing the oncoprotein CagA – is a strong risk factor for gastric cancer. Timothy Cover, M.D., professor of Medicine, and colleagues previously showed that high salt, which is also associated with gastric cancer risk, increased H. pylori expression of CagA in vitro.

Now, in studies led by postdoctoral fellow Jennifer Gaddy, Ph.D., the researchers have analyzed the effect of a high-salt diet on H. pylori-induced gastric cancer in a gerbil model. They report in Infection and Immunity that gerbils infected with CagA-positive strains of H. pylori and fed a high-salt diet had more severe gastric inflammation and a higher rate of cancer compared to gerbils fed a regular diet. Gerbils infected with CagA-negative strains did not develop cancer, regardless of diet. Infected animals on the high-salt diet had increased CagA expression, consistent with in vitro results.

The findings indicate that a high-salt diet potentiates H. pylori’s carcinogenic effects and suggest that lowering dietary salt may reduce the risk of H. pylori-associated gastric cancer in high-risk populations.

This research was supported by grants from the National Institute of Health (AI068009, CA116087, AI102568, DK058587, CA077955) and by the Departmnent of Veterans Affairs.