All sugars are not equal, according to scientists. A new study found that the mortality rate in mice increased when they were fed high-fructose corn syrup versus sucrose or table sugar.
Professor Wayne Potts and his team at the University of Utah and Children’s Hospital Oakland Research Institute in California will be publishing the study in The Journal of Nutrition. In the study, they fed mice sugars comparable to the amount that many Americans eat, at about twenty-five percent of total calories. An estimated thirteen to twenty-five percent of Americans eat this type of diet. In other areas of the world, only about eight percent of added sugar is high-fructose corn syrup, but in the U.S. this rises to about forty-two percent of added sugars. The rest of American sugar consumption is made up of forty-four percent sucrose and about fourteen percent combinations fructose and glucose, such as honey, molasses, and fruit concentrate.
The study involved feeding both male and female mice diets of either fructose-glucose, like what is found in high-fructose corn syrup, or sucrose. After forty weeks, the researchers put the mice together with a diet of fructose-glucose monosaccharides so that they would be in the same environment, then monitored their mortality.
Both groups of male mice showed no differences in reproduction, survival, and territorial behavior in the study. However, the story was not the same for the female mice. The female mice who had been on the fructose-glucose diet produced more than twenty-five percent less offspring and had death rates one point eight seven times higher than the sucrose dieters. It seems that eating a diet high in fructose-glucose, similar to the diet of many Americans, was bad for mouse health.
The researchers speculated that the females were more affected by the diet than the males because of the high amounts of energy required for nursing offspring while producing the next litter. Since the effects of the previous diet persisted even as the diet changed, the researchers also speculate that the sugars affect gut microbes. Some bacteria may favor one sugar over another, since they have different molecular arrangements. Both types of sugar contain both fructose and glucose, but in sucrose these two types of sugar are chemically bonded while in corn syrup these molecules are separate, called monosaccharides. All cells can use glucose, but only liver cells can break down fructose.
Although the study involved mice, it could have implications for humans. If the high fructose diet is bad for the mice, chances are it is bad for people too. Researchers had already noted that diabetes and obesity had increased in the mid nineteen-seventies, which was correlated with both higher sugar intake and the type of sugar eaten by Americans. While diets had previously contained mainly sucrose, that switched to about half and half with high-fructose corn syrup.
Although more research is needed, this study could prompt changes in the American food industry. While cutting back on sugar is still important for health, paying attention to the type of sugar consumed could help dieters get their health back on track. The World Health Organization had previously advised cutting back the recommended maximum daily sugar intake to help tackle obesity. It seems that future recommendations are needed to at least change the type of sugar that is added to the American diet.