Jet lag could trigger diabetes, according to new research.

Losing a single night's sleep affects the liver's ability to produce the glucose controlling hormone insulin, warn scientists.

This increases the risk of developing diseases linked to metabolism - such as type 2 diabetes and fatty liver disease.

In experiments blood sugar levels soared in mice kept awake for six hours when they should have been asleep - as happens with humans during long haul flights.

Harmful fats called triglycerides rose by more than two thirds in their livers - after just one session of going without kip. Glucose also increased dramatically.

Elevated liver triglycerides are associated with insulin resistance - the inability of the body to process the chemical properly.

In addition, lack of sleep changed the expression of enzymes that regulate metabolism in the liver.

The Japanese team said: "Losing just six hours of sleep could increase diabetes risk. Sleep deprivation alters liver metabolism and fat content."

Sleep deprivation has been linked to eating more, doing less exercise and being more prone diabetes.

But Dr Fumika Shigiyama, of Toho University, Japan, explained: "It was not clear whether glucose intolerance was due to the changes in food intake or energy expenditure or to the sleep deprivation itself."

So her team split male lab rodents into two groups with one kept awake for six hours each night with "gentle handling". The others acted as a control, sleeping as desired.

Unlimited supplies of high fat food and sugary water were on offer to both sets before the study began - mimicking the lifestyle related diet choices of people. There was also a limited opportunity for physical activity.

Immediately after the trial period the researchers measured fat and glucose levels in the livers of the mice.

The researchers said: "Blood glucose levels were significantly higher in the sleep deprivation group than controls after one six hour session of wakefulness."

Dr Shigiyama said the findings published in the American Journal of Physiology--Endocrinology and Metabolism have important implications for humans.

She said: "Intervention studies designed to prevent sleep deprivation-induced fatty liver disease and insulin resistance should be performed in the future."

Brits are among the most sleep deprived people in the world. Almost four in ten adults say they do not get enough.

There are more than 4 million diabetes patients in the UK, with about nine in ten having the type 2 form linked to obesity and inactivity.

Added the researchers: "Sleep deprivation is associated with increased risk for type 2 diabetes. However, the underlying mechanisms remain elusive.

"The aim of this study was to investigate the mechanisms of sleep deprivation-induced glucose intolerance in mice with a special focus on the liver.

"A single six hour sleep deprivation by the gentle handling method under fasting condition induced glucose intolerance.

"Glucose production was significantly increased, as was liver triglyceride content, by 67.9%, in the sleep deprivation group, compared with freely sleeping control mice."

They believe the phenomenon was due to sleep deprivation increasing oxidation of blood fats in the liver.

Recent research by the University of Bristol suggested a lack of sleep was putting some people at a greater risk of obesity and type 2 diabetes.

It analysed the sleeping habits of more than 500 participants and found those losing sleep on weekdays were more likely to develop the conditions.

The team said the action of throwing the body clock out of sync can disrupt the natural rhythm of hormones in the body that can put the body into a pre-diabetic state and lead to a host of health problems.