'Internal distillery causes liver disease'

Fatty liver disease is associated with obesity

Scientists believe a common liver disease may be caused by the production of alcohol within the body.

Fatty liver disorder is thought to affect around one in four people in developed countries. It particularly affects obese people.

Obesity changes the way the intestines propel their contents from one end to the other

Dr Anna Mae Diehl, Johns Hopkins University

The condition is currently untreatable, and one in ten sufferers go on to develop cirrhosis of the liver, which in turn increases the risk that cancer will develop in the organ.

The damage caused to the liver is identical to that associated with heavy alcohol abuse.

Dr Anna Mae Diehl, of Johns Hopkins University in Baltimore, Maryland, believes this is no coincidence.

She told New Scientist that alcohol could also be the cause of the symptoms of fatty liver disease.

However, in this case the problem was not alcholism, but the production of alcohol by an internal distillery within the body itself.

Scientists know that liver cells produce fats when they metabolise alcohol.

Dr Diehl thinks undigested food might stay in the intestines of obese people for longer.

This could allow normally harmless gut bacteria to ferment the food and produce alcohol, which would then cause fat to form in the liver.

Intriguing hypothesis

Dr James Neuberger, an expert on obesity-related fatty liver disorder at the Queen Elizabeth Hospital in Birmingham, told New Scientist: "It's an intriguing hypothesis.

"Many people with sluggish bowels don't develop the disorder - but it could be an explanation."

Dr Diehl's team tested the theory on mice genetically engineered to be obese.

The mice were fed on a diet that did not contain alcohol, and breath samples were taken as they aged.

Obesity-related fatty liver disorder usually develops in older animals and people.

The scientists found that older obese mice produced roughly five times as much ethanol as older lean mice, and all the obese mice developed fatty livers.

Dr Diehl said: "We think that obesity changes the way the intestines propel their contents from one end to the other.

"This means there are static periods when ethanol (alcohol) is overproduced."

The research is published in the journal Gastroenterology.