Scientists have shed light on why some people crave salty food, even when they know it can seriously damage their health.

The study helps researchers understand how the brain controls our appetite for salt, and how it impacts on blood pressure levels.

The findings suggest it could soon be possible to offer heart disease patients a medicine that helps them manage their salt intake and curb the adverse effects of high blood pressure.

Scientists modified mice to remove a gene (11β-hydroxysteroid dehydrogenase type 2 (11βHSD2)) in a small number of cells in the mouse brain. This gene is known to be linked with high blood pressure in humans but the way this is controlled is unclear.

Removing the gene caused the mice to develop a strong appetite for salt - when offered a choice of normal drinking water or saltwater, they consumed three times more saltwater than unmodified mice.

The trial also showed that the modified mice went on to experience high blood pressure for as long as they drank saltwater. When the saltwater was removed their blood pressure returned to normal.

Dexamethasone suppressed endogenous glucocorticoid and abolished the salt-induced blood pressure differential between genotypes. Salt-sensitivity in Hsd11b2.BKO mice was not caused by impaired renal sodium excretion or volume expansion; pressor responses to phenylephrine were enhanced and baroreflexes impaired in these animals.

The findings suggest that the 11βHSD2 gene plays an important role in controlling both the appetite for salt, and its effect in raising blood pressure, scientists say.

The team will now research whether an affordable drug - already used to treat heart disease in some countries - can help to bring salt intake under control in patients with heart failure.

The results have been published in the journal Circulation.

http://circ.ahajournals.org/content/early/2016/03/07/CIRCULATIONAHA.115.019341