A well-known television ad campaign sponsored by the Corn Refiners Association tells us that high-fructose corn syrup is “is made from corn, has no artificial ingredients, has the same calories as sugar and is okay to eat in moderation,” so we all feel better about digesting it, right?
Think again. High-fructose corn syrup may be public enemy number one when it comes to our diet. Even if you have a tendency not to pack in the calories, this sweetener may be the reason you are packing around extra weight.
In the 40 years since the introduction of high-fructose corn syrup as a cost-effective sweetener in the American diet, rates of obesity in the U.S. have skyrocketed, according to the Centers for Disease Control and Prevention. In 1970, around 15 percent of the U.S. population met the definition for obesity; today, roughly 1/3 of the American adults are considered obese, the CDC reported.
High-fructose corn syrup is found in a wide range of foods and beverages, including fruit juice, soda, cereal, bread, yogurt, ketchup and mayonnaise. On average, Americans consume 60 pounds of the sweetener per person every year.
“Some people have claimed that high-fructose corn syrup is no different than other sweeteners when it comes to weight gain and obesity, but our results make it clear that this just isn't true, at least under the conditions of our tests," said psychology professor Bart Hoebel, who specializes in the neuroscience of appetite, weight and sugar addiction at Princeton University.
Hoebel and his team discovered when rats are drinking high-fructose corn syrup at levels well below those in soda pop, they're becoming obese— every single one, across the board. “Even when rats are fed a high-fat diet, you don't see this; they don't all gain extra weight.”
And these rats aren’t just getting fat. They are exhibiting the characteristics of obesity, including substantial increases in abdominal fat and circulating triglycerides, says Princeton graduate student Miriam Bocarsly. In humans these characteristics are known factors for high blood pressure, coronary artery disease, cancer and diabetes.
When male rats in the Princeton study were given water sweetened with high-fructose corn syrup in addition to a standard diet of rat chow, the animals gained much more weight than male rats that received water sweetened with table sugar, or sucrose, along with the standard diet. The concentration of sugar in the sucrose solution was the same as is found in some commercial soft drinks, while the high-fructose corn syrup solution was half as concentrated as most sodas.
In addition to causing significant weight gain in lab animals, long-term consumption of high-fructose corn syrup also led to abnormal increases in body fat, especially in the abdomen, and a rise in circulating blood fats called triglycerides. The researchers say the work sheds light on the factors contributing to obesity trends in the United States.
The rats became obese by drinking high-fructose corn syrup, but not by drinking sucrose. The critical differences in appetite, metabolism and gene expression that underlie this phenomenon are yet to be discovered, but may relate to the fact that excess fructose is being metabolized to produce fat, while glucose is largely being processed for energy or stored as a carbohydrate, called glycogen, in the liver and muscles.
The research was supported by the U.S. Public Health Service.
Lynette Summerill, is an award-winning journalist who lives in Scottsdale, Arizona. In addition to writing about cancer-related issues, she writes a blog, Nonsmoking Nation, which follows global tobacco news and events.