Eating too much salt may contribute to development of a severe type of fatty liver disease even in people who are not overweight, a study has revealed.

Researchers said this suggests fatty liver disease may develop through different biological pathways in obese people and those who are a healthy weight.

They found that a diet that is high in salt produced relatively little fat accumulation in the liver but significant inflammation and scarring.

Scientists say the findings could help explain why treatments designed for obesity-associated fatty liver disease may not work as well in slim patients, and point toward more tailored approaches.

They added that some lean patients can have comparatively little liver fat yet still face a high risk of serious complications.

To investigate, scientists from Duke-NUS Medical School in Singapore and University College London developed the first diet-induced mouse model of lean fatty liver disease, feeding mice a fatty liver disease-inducing diet with added high salt.

They found that excess dietary salt triggered liver inflammation and scarring in non-obese mice, suggesting it could play a role in fatty liver disease in people who are not overweight.

Dr Zhou Jin, from Duke-NUS Medical School, said: ‘Our findings suggest that lean fatty liver disease is not simply the same disease occurring in a thinner person.

‘While obesity-associated fatty liver disease is closely linked to excess fat accumulation, our model shows that high dietary salt can alter liver metabolism and activate inflammatory pathways even without obesity.’

In the UK, fatty liver disease affects about a third of adults and is linked to obesity, high cholesterol and type 2 diabetes. Most people with the condition do not have symptoms.

The condition can progress to inflammation, scarring and, in severe cases, liver failure.

Too much salt raises blood pressure, increasing risk of heart attacks and strokes. The NHS advises adults to eat no more than a level teaspoon of salt a day.