Researchers find corn syrup worse than sugar for weight
In two studies, the researchers looked at the effects on rats when they ate high fructose corn syrup. The first study showed that rats fed a diet of water sweetened with high fructose corn syrup for eight weeks, in addition to rat chow, gained more weight than those who drank water mixed with table sugar.
The second study, which examined the long term effects of high fructose corn syrup consumption, followed rats over a period of six months. The rats drinking the corn syrup solution had higher abdominal body fat than the sucrose solution group.
Nicole Avena, a visiting research associate from the University of Florida who worked on the study, said that the researchers’ primary motivation was to compare sucrose to high fructose corn syrup to determine if they produce different effects on body weight.
Miriam Bocarsly ’06 GS, who also worked on the project, said in an e-mail that the studies’ results do not “immediately translate to humans.”
“It’s important to point out that this is a very specific set of studies, done in rats,” she explained, adding that “I’m not a medical doctor or clinician, I am a scientist, and we have some interesting findings.”
Avena noted that it is not possible to proportionally approximate how much high fructose corn syrup humans would have to consume in order to gain as much weight as the rats because the animals metabolize calories differently from humans. She added that the metabolic processes differ in individual humans as well.
Avena said that an adapted version of their studies could be conducted on human subjects to see if the same results would occur, though she added that such studies would be conducted elsewhere, since Hoebel’s laboratory does not conduct clinical trials.
If further research determines that high fructose corn syrup leads to weight gain in humans than other sugars do, it would provide important evidence to inform efforts to lower obesity.
High-fructose corn syrup is presently used more commonly than sucrose as a sweetener in the American diet, Avena said. Americans consume 60 pounds of the sweetener per person annually. Corn syrup is inexpensive sweetener, in part because of billions of dollars of government subsidies to corn producers.
Avena said that she hopes the Food and Drug Administration or other government agencies consider their findings and those of other studies in future planning, though she said that the research team does not plan to lobby for policy change based on its findings.
“Our information is out there for people to consider and interpret,” she said. “We are research scientists, basically, just interested in understanding why people over-eat and gain weight. There are other people out there who make policy decisions, and we hope that this study and others like it might have some influence.”
Some past studies have shown that fructose causes an increase in body weight, Avena said. Fewer studies, however, have looked at the effects of high fructose corn syrup. Avena noted that there there are some differences between the two sweeteners. As one example, high-fructose corn syrup contains slightly more fructose: It contains 55 percent fructose, whereas sucrose is broken down in the body to 50 percent fructose and 50 percent glucose.
Avena said that data from studies on fructose, in addition to clinical research, could help to conclusively link high fructose corn syrup to obesity, but more research is needed before definitive claims can be made.
Another line of research conducted in the Hoebel laboratory has been the study of sugar addiction.
“We have published quite a few studies showing that rats will become addicted to sucrose,” Avena said. “They’ll show signs of withdrawal, craving and brain changes that are akin to what you’d see in an animal that’s addicted to a drug of abuse.”
She added, however, that there is no current evidence for addiction to high fructose corn syrup.
For the research team, this study is only the beginning.
Elyse Powell ’11, an undergraduate on the research team, said that they plan to both replicate and follow up on the experiment.
“The ultimate goal would be to understand what makes high fructose corn syrup different from sucrose, and how these sweeteners can affect the body, brain and behavior,” Avena said.
Hoebel could not be reached for comment.