Is Sugar Toxic?

Human-relevant levels of added sugar consumption increase female mortality and lower male fitness in mice. By James S. Ruff and colleagues. Nature Communications 2013;4:online

What is the problem and what is known about it so far?

Supermarkets are filled with products containing added sugar—sucrose (table sugar) or high-fructose corn syrup. As a result, people are consuming more added sugar now than in decades past, and several studies have linked sugar intake with a number of diseases including type 2 diabetes, cancer, and heart disease. Animal research also suggests that sugar is a health hazard, but these studies often test sugar levels far higher than what a human typically eats.

Why did the researchers do this particular study?

The researchers wanted to explore whether mice that eat levels of sugar that are on par with a typical human diet—25 percent of total calories—are worse off than mice that ate no sugar.

Who was studied?

The researchers included mice that were derived from wild rodents so they would still possess competitive nesting, mating, and other behaviors found only in wild animals.

How was the study done?

The researchers fed half the mice a diet with 25 percent of its calories coming from glucose and fructose in a ratio similar to what is found in sucrose and high-fructose corn syrup. The other mice received 25 percent of their calories from cornstarch, a complex carbohydrate. The mice were then all implanted with a tag to help researchers identify them and keep track of their movements. The mice were housed together in a cage that measured 115 feet square and contained both optimal nesting sites (sheltered) and nonoptimal nesting sites (out in the open). The researchers proceeded to monitor mouse interactions, health, and reproduction.

What did the researchers find?

Nearly twice as many sugar-fed female mice died in the study compared to cornstarch-fed ones. Plus, the cornstarch-fed females had more babies than the sugar-fed females. As for the male mice, those with a sugary diet ended up in the suboptimal nesting sites more often than the cornstarch-fed mice and so were less desirable mates, leading to fewer offspring.

What were the limitations of the study?

The study was done in mice, so it's unclear if the results would translate to humans.

What are the implications of the study?

The study suggests that sugar, at the quantities people typically consume it, may have a negative effect on your health.

  • Last Reviewed: January 15, 2014
  • Last Edited: February 14, 2014

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