Florida Researchers Find Consuming Fructose Can Suppress Leptin Hormone, Lead To Obesity

Gainesville, FL (AHN) - A first-ever study found that eating too much fructose can induce leptin resistance and make it easier to become fat.

The new study done with rats showed that consuming too much fructose can create leptin resistance and easily lead to becoming overweight when combined with a high-fat, high-calorie diet.

Previous studies had shown that being leptin resistant can lead to rapid weight gain on a high-fat, high-caloric diet, but this was the first study to show that leptin resistance can develop as a result of high fructose consumption.

This study was also the first to find that leptin resistance can develop with little indication that it is happening. Leptin is a hormone that acts as a regulator in the body.

Leptin plays a role in helping the body balance food intake with energy expenditure. Leptin resistance occurs when the body no longer responds to the leptin it produces. Leptin Resistance is associated with weight gain and obesity in the face of a high-fat, high-calorie diet.

Table sugar and high-fructose corn syrup are about 50 percent fructose and have been added to a growing number of foods.

University of Florida researchers tested their hypothesis that a high-fructose diet could lead to leptin resistance, which in turn could lead to exacerbated weight gain by feeding two groups of rats the same diet except one group consumed a lot of fructose while the other group consumed no fructose.

After six months there was no difference in food intake, body weight, and body fat or in levels of leptin, glucose, cholesterol or insulin found in the blood rats on the high-fructose and the rats on the fructose-free diets.

There was only one difference at the end of six months, that was that the rats on the high-fructose diet had higher levels of triglycerides in their blood. So researchers injected all the rats with leptin to see if they would respond by eating less. What they discovered was that the rats on the low-fructose diet did respond to the leptin by eating less, while the rats on the high-fructose were leptin resistant and and did not lower their food intake in response to being given leptin.

Researchers at the University of Florida College of Medicine in Gainesville said the first six months of the study showed that leptin resistance can develop silently.

"Usually, leptin resistance is associated with obesity, but in this case, leptin resistance developed without obesity," researcher Alexandra Shapiro said in a statement. "This was very surprising."

"The presence of high fructose alters the way leptin works, fooling the brain so that it ignores leptin," researcher Philip J. Scar pace said.

Consumers should be cautious about what they eat, checking labels to see how much sugar the items contain, Shapiro said.

Researchers say they want to perform future studies to discover whether leptin resistance can be reversed by removing or reducing the fructose content of the diet.

Along with Shapiro and Scarpace, the other researchers were Wei Mu, Carlos Roncal, Kit-Yan Cheng, Richard J. Johnson. Findings from their study appears in the American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, published by The American Physiological Society.