In the United States and elsewhere, high fructose corn syrup is ubiquitous in soft drinks, sweet baked goods and many processed foods. But a new study shows that as a nation's rate of fructose intake rises, so do levels of type 2 diabetes.
The study cannot prove a cause-and-effect link, but it does conclude that diabetes prevalence is about 20 percent higher in countries where use of the sweetener is high, relative to those where it is not.
The association between high fructose corn syrup intake and diabetes risk persisted regardless of an individual's overall sugar intake or obesity status. According to the study authors, that suggests that there's something special about the sweetener that's boosting diabetes risk beyond what other sugars would.
"The 20 percent higher prevalence of type 2 diabetes in countries using a lot of high fructose corn syrup was not explained by population differences in terms of obesity [levels]," said study lead author Michael Goran, professor of preventive medicine and director of the Childhood Obesity Research Center at the University of Southern California in Los Angeles.
"So, there's some other factor, maybe several interrelated factors, over and above obesity, that contributes to diabetes," he said. "High fructose corn syrup and the way it is metabolized may very well be one of them," he added.
The findings were published online Nov. 27 in Global Public Health.
Type 2 diabetes, which is typically tied to obesity, remains one of the most common causes of death worldwide. According to Goran's team, nearly 8 percent of people worldwide could be diabetic by 2030. Much of the rise is taking place in the developing world, as diets shift to more Western fare high in carbohydrates and sugars.
But are all sugars created equally? Goran and his team say prior studies have suggested that fructose follows a different digestive path than glucose, metabolizing in the liver independently of insulin. From there, they said, it can readily turn into fat.
In their study, the researchers analyzed data on diabetes prevalence and body mass index (BMI, a measurement based on height and weight) collected in 2000, 2004 and 2007 by the Global Burden of Metabolic Risk Factors Collaborating Group. This information came from adults over the age of 20 across 199 nations.
The team also collected United Nations data on food consumption across various countries to assess to what degree various sugars and cereals were staples of local diets. In the end, Goran's team was able to get information on high fructose corn syrup intake from 43 countries.
The investigators found that BMI, daily calories and total sugar intake (including sugars of any kind) were comparable across countries, regardless of the level of high fructose corn syrup intake.
Still, countries that ranked high in use of the sweetener also had significantly higher rates of diabetes than countries with lower rates, Goran's group reported.
Americans were by far the biggest consumers of high fructose corn syrup, at 55 pounds per person per year. According to the researchers, beginning in the late 1990s, the sweetener had comprised about 40 percent of all sugars found in food products in the United States and it remains the number one sweetener in soft drinks.