Sugar science: Fructose more ‘toxic’ than sucrose, suggests mouse study
The study, published in The Journal of Nutrition, investigated the effects of comparable amounts of sucrose- or fructose/glucose-containing diets on key organism-level health measures including longevity, reproductive success, and social dominance.
The US team behind the research found that consumption of human-relevant levels of a fructose-glucose akin to high-fructose corn syrup is more harmful than an isocaloric amount of sucrose for a number of health measures in female mice.
"This is the most robust study showing there is a difference between high-fructose corn syrup and table sugar at human-relevant doses," commented Professor Wayne Potts from the University of Utah – the study’s senior author.
The team reported that consumption of fructose-glucose mixture was associated with a reduction of both the reproduction and lifespan of female rodents compared to those consuming sucrose.
No differences in survival, reproduction or territoriality of male mice on the high-fructose and sucrose diets, they said.
The research was funded by the National Institutes of Health and National Science Foundation.
The new study is the latest in a series that used a new, sensitive toxicity test developed by Potts and colleagues. It allows house mice to compete in the semi-natural environment of room-size ‘mouse barns.’
The mice in the new study were unrelated, house-type mice, rather than inbred lab mice, because the former compete with each other naturally. For 40 weeks, the mice were fed either a diet with 25% of total calories as added fructose and glucose monosaccharides or as sucrose.
Then 160 mice were released into six mouse barns to compete for food, territory and mates for 32 weeks. Each of the 377-square-foot mouse barns held eight to 10 male mice and 14 to 20 females, said the team.
After eating different sugar diets before entering the mouse barns, all the mice ate the fructose-glucose monosaccharide diet while competing in the barns, where they roamed together and couldn't be kept on different diets, said the team.
Female mice that had initially been fed on the fructose-glucose diet had death rates 1.87 times higher than females on the sucrose diet. They also produced 26.4% fewer offspring, said Potts and colleagues.
However, the team found no differences in males on the two diets in terms of survival, reproduction or ability to compete for territory.
Regardless of sex, the researchers also found no difference between mice on the two diets when it came to food intake, weight gain or glucose tolerance.
The team noted that sucrose is broken into fructose and glucose monosaccharides before the body absorbs it. They therefore suggested that whatever caused the different mortality and reproduction in females on the two kinds of sugar diets "has to happen at the point of absorption or before - not once it is in the bloodstream, liver or brain.”
"We speculate that the different sugars could favour different microbes in the guts of mice,” suggested James Ruff, the study's first author.
“Other research has shown differences in bacterial communities in the gut to be associated with metabolic diseases in rodents and in humans,” he commented. “It's possible one form of sugar causes more bacteria to get across your gut than another."
Source: The Journal of Nutrition
Published online ahead of print, doi: 10.3945/jn.114.202531
“Compared to Sucrose, Previous Consumption of Fructose and Glucose Monosaccharides Reduces Survival and Fitness of Female Mice”
Authors: James S Ruff , et al
Points to Consider
Posted by Ellen Stokes, MS, RD, LD,