Fructose diets more harmful than sugary ones

style="float: right; margin-bottom: 10px; font-weight: 600;"Sat 24th Jan, 2015


It's hard to escape sugar. It's not just about resisting junk food.

Added sugars, like high fructose corn syrup, get snuck into a lot of our foods.

"We know that across the board added sugar causes problems," says James Ruff, postdoctoral fellow in biology at the University of Utah.

But Ruff and his team wanted to investigate which added sugar is worse: high fructose corn syrup or table sugar.

For their study, published in The Journal of Nutrition, they fed one group of mice a high fructose corn syrup-based diet. The other half got sucrose, or table sugar.

Sugar made up 25% of each group's calories. That's slightly higher than the average American's sugar intake, but not unusual in the States.

Ruff's background in evolutionary biology guided him and his team toward a unique approach. Rather than monitoring mice in cages, they built a huge exposure for the mice to simulate life in the wild. "We had really good success in seeing behaviors that's harder to see in caged environments," Ruff says.

Raised on their respective diets, the mice had to compete for food, water, and territory. From the evolutionary biologist perspective, the mice with the better diet would have more pups, live longer, and claim more territory.

The diet difference really took a toll on the female mice. The "fructose" females had nearly twice the mortality rate as the "sucrose" females. They also had fewer pups.

Ruff is quick to caution that the study doesn't mean sucrose is "healthier" than fructose. It just suggests that it's less bad--in female mice, specifically.

"To translate to humans, we need to figure out why the females were more harmed by the fructose/glucose diet and then see if we can get similar measures in people," Ruff says.

Fructose has gained a bad reputation in other labs, however.

High fructose corn syrup might mean greater health risks, says Richard Johnson, professor in the department of medicine at the University of Colorado.

Johnson's studies suggest drinks with high fructose corn syrup cause higher blood pressure. Fatty liver health problems have also tended to crop up more in mice with fructose/glucose diets than in mice with sucrose diets.

"Fructose in particular is pretty bad, because it's handled by the liver," says Michael Goran, professor of preventive medicine at the University of Southern California.

Fructose from soda and other high-sugar products can swamp the liver, increasing risk of fatty liver, high cholesterol, and heart disease.

Fructose's sins don't make sucrose a saint. The real point is to decrease sugar consumption overall. Eating whole foods and diluting juice can help.

"First, let's worry about lowering sugar intake," says Ruff. "Then we can worry about what type of sugar."

(Photo Credit: Coralie Ferreira; No modifications have been made to this image available via Creative Commons license.)



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