A new study shows that when mice consume as much extra sugar as the human equivalent of three cans of soda a day, females die twice as fast as normal. Males, meanwhile, are 25 percent less likely to hold territory and reproduce.
Despite numerous studies that demonstrate the harmful effects of sugar on humans, the beverage and corn refining industries say that this animal research is flawed.
The study appeared Tuesday in the journal Nature Communications.
Linking Soda to Mortality
The National Institutes of Health (NIH) and the National Science Foundation (NSF) funded the study, performed by biology professor Wayne Potts of the University of Utah and James Ruff, who recently earned his doctorate there.
Although the researchers said they know of no studies that link sugar to higher morbidity and lower reproductive rates in humans, many experiments have pointed to increased rates of high blood pressure, obesity, and diabetes among people who have a sweet tooth, and a fondness for soda in particular.
The scientists who conducted the new research say that previous studies involved giving mice sugar at levels much higher than a diet of 25 percent added sugar, or three sodas a day. This is a level of added sugar that many humans regularly consume and believe is safe.
“We have now lowered the level of added sugars that produce an adverse outcome down to what was previously considered safe,” Potts told Healthline. “No government agency would make safe levels if they knew animals studies showed that there were adverse reactions at those lower levels.”
Potts and his team monitored the animals' body weight as well as their fasting insulin, glucose, and triglyceride levels. In females only, those on the added sugar diet had reduce glucose tolerance. Perhaps surprisingly, the mice fed added sugar did not gain weight.
The mice were given the added sugar in their food, beginning at the age of four weeks, which is when mice become sexually mature, Potts said.
The Sugar Debate Rages On
In a statement to Healthline, the American Beverage Association (ABA) stressed that the University of Utah study was performed on mice, not people. “The findings of this mouse study must be viewed within context. These mice were fed a diet that included a fructose and glucose mixture—not a sugar-sweetened beverage—every single day from infancy until the end of their lives. This is not a reflection of real life for humans.”
The Corn Refiners Association also sent a statement to Healthline in an effort to debunk the study. “Mice are not humans, and it simply is not possible to know how humans would react without testing them in the same way. Mice do not eat sugar as a part of their normal diet, so the authors are measuring a contrived overload effect that might not be present had the rodents adapted to sugar intake over time.”
But Ruff told Healthline that house mice eat the same things people do, and are genetically more than 80 percent identical to humans. “The nice thing about house mice is that they live with us. In a house, they eat what's there. Sugar is not foreign to the mouse.”
Three researchers at Yale University analyzed 88 studies for a paper published in 2007 in the American Journal of Public Health. “Available data indicate a clear and consistent association between soft drink consumption and increased energy intake,” the report concluded. “Given the multiple sources of energy in a typical diet, it is noteworthy that a single source of energy can have such a substantial impact on total energy intake. This finding alone suggests that it would be prudent to recommend population decreases in soft drink consumption.”
The Yale scientists added, “The fact that soft drinks offer energy with little accompanying nutrition, displace other nutrient sources, and are linked to several key health conditions such as diabetes is further impetus to recommend a reduction in soft drink consumption.”