While previous studies have found sugar to have detrimental effects on health, they generally used amounts much higher than most people actually eat, said the study's co-author, James Ruff of the University of Utah.
"I think the big takeaway is the level of sugar we readily eat and think is safe causes major health declines in mice," Ruff told the Salt Lake City Tribune. "We're not just talking about some minor metabolic thing. We're taking about increased rates of death and [lower rates] of reproduction."
The research was published online August 13 in the journal Nature Communications.
Researchers fed mice sugar as 25 percent of their diet -- equivalent to about 500 calories on a 2,000-calorie diet for humans -- for six months. Interestingly, it didn't make the mice fatter. "Our mice would have passed their physical," Ruff said. If they had lived, that is.
About 35 percent of the high-sugar females died, twice the 17 percent death rate for the female control mice. Those who ate more sugar initially had higher birth rates, perhaps due to the extra energy the sugar gave them. The rates declined as the study progressed, partly because more of them died. The male mice fed the extra sugar were less likely to defend their territory and reproduce, siring 25 percent fewer offspring and holding 26 percent less territory.
Ruff notes that sugar consumption in the American diet has increased 50 percent since the 1970s, accompanied by a dramatic increase in metabolic diseases such as diabetes, obesity, fatty liver and cardiovascular disease. Studies indicate that today, between 13 and 25 percent of Americans get a quarter or more of their calories from added sugars.
The researchers said mice were "an excellent mammal to model human dietary issues" because they've been living among people and consuming the same food for thousands of years. "Our results provide evidence that added sugar consumed at concentrations currently considered safe exerts dramatic adverse impacts on mammalian health," they conclude.
Interestingly, the study's results were similar to the lab's findings on inbreeding in mice. The scientists say the level of health degradation is "almost identical" from added sugar and from cousin-level inbreeding.
"Would you rather be on the American diet ... or have parents be full cousins?" said senior author Wayne Potts, a biology professor. "This data is telling us it's a toss up."
What a Utah way to look at it.