The germ Helicobacter pylori is the cause of most stomach ulcers, but new research in Alimentary Pharmacology & Therapeutics suggests that treating the bacteria is linked to weight gain.

It is estimated that 50% of the global population may be infected with H. pylori; however, only 20% of infected people experience symptoms. New evidence suggests that patients treated for the infection developed significant weight gain compared to subjects with untreated H. pylori colonization.

By reviewing data taken from forty-nine studies with data from ten European countries, Japan, the U.S. and Australia, Professor Gerald Holtmann identified a correlation between prevalence rates for H. pylori and obesity.

"The rate of obesity and overweight were inversely and significantly correlated with the prevalence of H. pylori infection," said Professor Holtmann. "The gradual decrease of the H. pylori colonisation observed in recent decades could be causally related to the obesity endemic observed in the Western world".