Scientists Warn Diets High in Fructose May Harm Liver in Some

Tuesday, September 18, 2012 5:43

Increased consumption of this sugar linked to altered metabolism, energy balance stores.

Obese people with type 2 diabetes who consume increased amounts of fructose—a simple sugar—may have high levels of uric acid and a reduction in liver energy stores, researchers say.
High uric acid, or hyperuricemia, is linked to lower levels of liver adenosine triphosphate (ATP), a compound involved in transferring energy between cells, scientists from Duke University Medical Center explained in a news release.

The researchers, who published their new report in the September issue of the journal Hepatology, noted that energy depletion in the liver could result in liver damage for those with the metabolic condition known as non-alcoholic fatty liver disease and in those at risk for the condition. They stressed that the public should be aware of these risks associated with a diet high in fructose.

“There is an alarming trend of increased rates of obesity, type 2 diabetes and [non-alcoholic fatty liver disease] in the U.S.,” lead author Dr. Manal Abdelmalek said in the journal news release. “Given the concurrent rise in fructose consumption and metabolic diseases, we need to fully understand the impact of a high-fructose diet on liver function and liver disease.”

Fructose is a simple sugar found in fruits and vegetables. It also is combined with glucose to manufacture high-fructose corn syrup, a sweetener in many packaged foods such as cereal and soda.
The researchers examined nearly 250 obese and diabetic adults participating in the Look AHEAD Study. The participants were asked to estimate the amount of fructose they consumed.

Liver ATP and uric acid levels also were measured in more than 100 patients who participated in a second study. Researchers measured the difference in liver ATP content between patients with low fructose consumption (less than 15 grams per day) and those with high fructose consumption (greater than 15 grams per day).

The study revealed that participants with high dietary fructose consumption had lower liver ATP levels when the study began and a more significant change in ATP after the fructose test. The researchers also noted that those with high uric acid levels had lower ATP stores following high fructose intake.
Based on their findings, the researchers suggested uric acid, which is produced by the breakdown of natural food substances known as purines, may serve as a marker for increased fructose consumption and low levels of liver ATP.

“High fructose consumption and elevated levels of uric acid are associated with more severe depletion of liver ATP,” Abdelmalek said in the news release. “Our findings suggest that increased dietary fructose intake may impair liver ‘energy balance.’ Further research to define the clinical implications of these findings on metabolism and NAFLD is necessary.”

Although the study found an association between a diet high in fructose and liver risks in certain people, it did not prove a cause-and-effect relationship.