Sugar overload of any type does not bode well for your waistline or your health, but a new study suggests that certain sugars trigger more health problems than others. Consuming large quantities of fructose, a sugar found in high fructose corn syrup used to sweeten soft drinks and processed foods, may induce metabolic changes that lead to increased risk of type 2 diabetes and heart disease, according to a study published today in The Journal of Clinical Investigation.  

 "The bottom line is that we've shown important biological and metabolic differences between the two major sugars [fructose and glucose] in the diet," says study co-author Peter Havel, a nutrition researcher at the University of California, Davis. But, he adds, more research is needed to justify any recommendations promoting or discouraging the consumption of certain sweeteners. 

Fructose (which imparts sweetness to fruits) and glucose (which makes up carbohydrates found in bread and pasta) are the most important simple sugars in our diet, Havel says. The growing consumption of fructose from high fructose corn syrup (which contains about 55 percent fructose and 45 percent glucose) found in soda, juices, and sweet snacks has led some to suspect it is a key culprit in the obesity epidemic.

To find out whether the sugars have different effects on human physiology, Havel and his colleagues studied the consumption of fructose- and glucose-sweetened beverages among 32 overweight men and women ages 40 to 72. Every day for 10 weeks, 17 study participants drank three bottles of fructose-sweetened drinks and 15 of them drank bevs sweetened with glucose. By the end of the study, the fructose and glucose-chugging groups had gained about the same amount of weight – an average of about 3.3 pounds (1.5 kilograms) -- but those in the fructose group accumulated about twice as much visceral fat, the kind that builds up around organs (rather than under the skin) and increases one's risk for developing type 2 diabetes and heart disease.

In addition, low-density lipoprotein (LDL or "bad" cholesterol) levels shot up by about 14 percent and insulin sensitivity dropped by about 17 percent in the fructose guzzlers; there were no such changes in the glucose group. 

"Over the long term, [these changes seen in the fructose group] would be expected to increase the risk for diabetes and cardiovascular disease," Havel says, but he cautions that the beverages used in the study are not representative of the drinks people typically consume. Havel says he recently launched a five-year study to try to determine the health effects of fructose and glucose on normal-weight people ages 18 to 40.

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