Fructose, found in fruit, honey, sugar and in many processed foods, could be a major player in rising obesity rates, say University of Florida (UF) researchers. They suggest that fructose may "trick" your body into thinking that you are hungrier than you should be. The scientists' studies in animals have revealed fructose's role in a biochemical chain reaction that triggers weight gain and other features of metabolic syndrome - the main precursor to type 2 diabetes. Interestingly, the researchers prevented rats from gaining weight by interrupting the way their bodies processed this simple sugar, even when the animals continued to consume it. Their findings, reported in Nature Clinical Practice Nephrology, add to growing evidence implicating fructose in the obesity epidemic.
Researcher Richard J. Johnson, said that although genetic predisposition was a factor in obesity, there was some other major environmental force driving this process. "Our data suggest certain foods and, in particular, fructose, may actually speed the process for a person to become obese," he said. Johnson cited the fact that Americans are consuming more fructose than ever; in soft drinks, jellies, pastries, ketchup, sugar, and corn syrup - a sugar substitute introduced in the early 1970s. Since then, fructose intake has soared more than 30 percent, and the number of people with metabolic syndrome has more than doubled worldwide, to more than 55 million in the United States alone.
"If you feed fructose to animals they rapidly become obese, with all [the] features of the metabolic syndrome, so there is this strong causal link," Johnson explained, "And a high-fructose intake has been shown to induce certain features of the metabolic syndrome pretty rapidly in people."
The UF research identified a rise in uric acid in the bloodstream that occurs after fructose is consumed. This temporary spike blocks the action of insulin, which typically regulates how body cells use and store sugar and other food nutrients for energy. If uric acid levels are frequently elevated, over time features of metabolic syndrome may develop, including high blood pressure, obesity and elevated blood cholesterol levels. "When we blocked or lowered uric acid, we were able to largely prevent or reverse features of the metabolic syndrome," Johnson said. "We were able to significantly reduce weight gain, we were able to significantly reduce the rise in the triglycerides in the blood, the insulin resistance was less and the blood pressure fell."
"We cannot definitively state that fructose is driving the obesity epidemic," Johnson continued. "But we can say that there is evidence supporting the possibility that it could have a contributory role - if not a major role. I think in the next few years we'll have a better feel for whether or not these pathways that can be shown in animals may be relevant to the human condition."
The UF findings suggest certain sugar carbohydrates are better than others, because some do not activate the uric acid pathway. "It may well be we don't need to cut out carbohydrates but just certain types of carbohydrates," Johnson concluded. "So this may be an alternative to the Atkins type of approach, which cuts out carbohydrates indiscriminately."
Source: University of Florida
