Red wine or even the juice from red grapes could induce fat burning when consumed in moderation, according to a new study at Oregon State University in the US.

The findings suggest this could be the basis of a useful dietary supplement for those who are overweight and could help individuals to manage metabolic disorders including fatty liver.

In the study, published in the Journal of Nutritional Biochemistry, the research team exposed laboratory-grown human liver and fat cells to extracts of four chemicals that occur naturally in dark-red Muscadine grapes.

Of the chemicals, the most potent was ellagic acid, which sharply stunted the growth of existing fat cells and prevented new ones from forming.

It also revved up the metabolism of liver cells, kicking fatty acids into action.

"We didn't find, and we didn't expect to, that these compounds would improve body weight," says lead author Neil Shay, a biochemist and molecular biologist at OSU, explaining that red wine shouldn't be looked upon as a miracle weight loss drug.

However, its fat-burning capabilities could improve liver function in overweight people, he says.

"If we could develop a dietary strategy for reducing the harmful accumulation of fat in the liver, using common foods like grapes," Shay said, "that would be good news."

Shay and his team fed a diet consisting of 60 percent fat to a test group of mice, while feeding the control group a normal diet containing 10 percent fat.

They supplemented the diets of some of the mice with mouse-sized portions of grape extracts, the rough equivalent of one and a half cups of grapes a day in human servings.

Over the course of 10 weeks, mice on the high-fat diet suffered the same consequences as humans would, including diabetic symptoms and fatty livers.

Yet mice that had been consuming the high-fat diet supplemented by grape extracts accumulated less fat in their livers and maintained lower blood sugar levels than those that did not receive the supplements.

In fact, ellagic acid lowered their blood sugar almost enough to match that of the mice who were fed the healthy diet.

Tissue analysis of the mice that ate the grape-supplemented high-fat diet indicated high activity levels of two proteins that metabolize fat and sugar called PPAR-alpha and PPAR-gamma.

Drugs for lowering blood sugar and triglycerides bring on the same effect, says Shay, who says his goal is not to replace medications but to help people make wise dietary choices.