Fructose more toxic than table sugar in mice

http://www.eurekalert.org/pub_releases/2015-01/uou-fmt122914.php

Public Release: 4-Jan-2015
University of Utah

When University of Utah biologists fed mice sugar in doses proportional to what many people eat, the fructose-glucose mixture found in high-fructose corn syrup was more toxic than sucrose or table sugar, reducing both the reproduction and lifespan of female rodents.

"This is the most robust study showing there is a difference between high-fructose corn syrup and table sugar at human-relevant doses," says biology professor Wayne Potts, senior author of a new study scheduled for publication in the March 2015 issue of The Journal of Nutrition.

The study found no differences in survival, reproduction or territoriality of male mice on the high-fructose and sucrose diets. The researchers say that may be because both sugars are equally toxic to male mice.

Both high-fructose corn syrup found in many processed foods and table sugar found in baked goods contain roughly equal amounts of fructose and glucose. But in corn syrup, they are separate molecules, called monosaccharides. In contrast, sucrose or table sugar is a disaccharide compound formed when fructose and glucose bond chemically.

Potts says the debate over the relative dangers of fructose and sucrose is important "because when the diabetes-obesity-metabolic syndrome epidemics started in the mid-1970s, they corresponded with both a general increase in consumption of added sugar and the switchover from sucrose being the main added sugar in the American diet to high-fructose corn syrup making up half our sugar intake."

James Ruff, the study's first author and a postdoctoral fellow in biology, says, "Our previous work and plenty of other studies have shown that added sugar in general is bad for your health. So first, reduce added sugar across the board. Then worry about the type of sugar, and decrease consumption of products with high-fructose corn syrup."

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The 2013 study found that when mice were fed either a diet with 25 percent calories in the form of added fructose and glucose monosaccharides or 25 percent calories from starch, females died at twice the normal rate and males were a quarter less likely to hold territory and reproduce.
The new study compared two groups of mice that were fed a healthy diet with 25 percent calories from processed sugars. One group ate a mix of fructose-glucose monosaccharides like those in high-fructose corn syrup. The other group ate sucrose.

Female mice on the fructose-glucose diet had death rates 1.87 times higher than females on the sucrose diet. They also produced 26.4 percent fewer offspring.

The new study found no differences in males on the two diets in terms of survival, reproduction or ability to compete for territory. But Potts said the 2013 study showed male mice were a quarter less likely to hold territory and reproduce on the fructose-glucose mix compared with starch. That, combined with the new findings, "suggests sucrose is as bad for males as high-fructose corn syrup," he says.

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An estimated 13 percent to 25 percent of Americans eat a diet that includes 25 percent or more of calories in the form of added sugars - the percentage of added sugars consumed by mice in the new study. "Added sugars" are sugars added during food processing or preparation and not already naturally in food, like in a piece of fruit.

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