Washington, Sept 21 : A new study has revealed that along with expanding waistlines, diets rich in rapidly-digested carbohydrates may also cause fatty liver, a condition that can lead to liver failure and death, a new study in mice has revealed.

If confirmed in humans, the findings suggest that fatty liver disease that is rampant among Americans as a by-product of the obesity epidemic may be avertable and can be treated through dietary changes.

The researchers, led by David Ludwig, MD, PhD, director of the Optimal Weight for Life program at Children’s Hospital Boston fed mice either a high- or a low-glycemic index diet.

High-glycemic index foods, including white bread, white rice, most prepared breakfast cereals and concentrated sugar, raise blood sugar quickly. Low-glycemic index foods, like most vegetables, fruits, beans and unprocessed grains, raise blood sugar slowly.

On the high-glycemic index diet, mice ate a type of cornstarch that is digested quickly whereas on the low-glycemic index diet, mice ate a type of cornstarch that is digested slowly. The diets had equal amounts of total calories, fat, protein, and carbohydrate, and the mice were otherwise treated identically.

After six months, the mice weighed the same. However, mice on the low-glycemic index diet were lean, with normal amounts of fat in throughout their bodies. Mice on the high-glycemic index diet had twice the normal amount of fat in their bodies, blood and livers.

When sugar melts out of high-glycemic index food, Ludwig explains, it drives up production of insulin, which tells the body to make and store fat. Nowhere is this message felt more strongly than in the liver, because the pancreas, which makes insulin, dumps the hormone directly into the liver, where concentrations can be many times higher than in the rest of the body. Fat build up in the liver, or fatty liver, is usually symptomless, but it increases the risk for liver inflammation, which can progress to hepatitis and, in some cases, liver failure.

“This is a silent but dangerous epidemic,” says Ludwig. “Just as type 2 diabetes exploded into our consciousness in the 1990s, so we think fatty liver will in the coming decade.”

A previous study found that Italians who ate higher-glycemic index diets had fattier livers, but the study wasn’t tightly controlled. The new study makes clear that the type of carbohydrate can cause fatty liver in animals, independent of other elements of diet or lifestyle.

“Our experiment creates a very strong argument that a high-glycemic index diet causes, and a low-glycemic index diet prevents, fatty liver in humans,” says Ludwig.

Ludwig and colleagues now hope to confirm this in a just-launched clinical trial – and to show that a low-glycemic index diet can reverse fatty liver in overweight children. The children, aged 8 to 17, will be randomized to either the low-glycemic diet or a low-fat diet.

Low-fat diets are currently the standard treatment, Ludwig says, but many children with fatty liver don’t respond to them. “We think it is a misconception that the fat you’re eating goes into the liver,” he says.

Ludwig, author of Ending the Food Fight: Guide Your Child to a Healthy Weight in a Fast Food/Fake Food World assumes that that obesity, sedentary lifestyles and increased consumption of refined carbohydrates are “synergistically” fuelling a fatty liver epidemic in children. Ironically, low-fat diets have only made matters worse, replacing fat with sugar or starchy foods that actually increase fat deposition in the body.

“Two low-fat Twinkies, billed as a health food, contain the same amount of sugar as an oral glucose tolerance test – a test used to determine how much sugar someone can digest,” Ludwig said.

He noted that the French delicacy pate de fois gras, the fatty liver of a duck or goose, is produced by over-feeding the animals with high-glycemic index grains.

The study appears in the September issue of the journal Obesity. (With inputs from ANI)