The nonprofit organization Center for Science in the Public Interest (CSPI) announced in March 2012 that a new chemical analysis of the caramel coloring used in colas, including Coke and Pepsi products, has been shown to cause cancer in animals. This carcinogenic substance is called 4-methylimidazole (4-MI), and is a byproduct of the ammonia used during the manufacturing process.

“When most people see ‘caramel coloring’ on food labels, they likely interpret that quite literally and assume the ingredient is similar to what you might get by gently melting sugar in a saucepan,” says Michael F. Jackson, executive director of CSPI. “Colorings made with the ammonia or ammonia-sulfite process contain carcinogens and don’t belong in the food supply. In any event, they shouldn’t be obscured by such an innocuous-sounding name as ‘caramel coloring.’”

In California, a food or beverage that contains more than 29 mcg of 4-MI must come with a warning notice. Products from Washington, D.C.-area stores that CSPI tested contained anywhere from 113 to 153 mcg, depending on the soda. CSPI reports that Pepsi products contained 145 to 153 mcg per 12 ounces. One sample of Coke contained 142 mcg per 12 ounces, while another had 146 mcg. 

According to a CSPI press release, “Based on California’s risk model, CSPI estimates that the 4-MI in the Coke and Pepsi products tested is causing about 15,000 cancers in the U.S. population.” Pepsi told CSPI that it uses a different coloring, which contains less 4-MI, in its soda sold in California.

Because the recently released tests were done on animals, there is some question as to how much a person needs to consume to put himself at risk of developing cancer. Regardless, CSPI believes this is such a threat to human health that in February 2011 it filed a petition with the U.S. Food and Drug Administration urging it to prohibit the use of 4-MI.

In addition to 4-MI, CSPI reports that the high-fructose corn syrup used to sweeten soft drinks is even more troubling because it has been linked to obesity, diabetes and other health problems. Wellness Times previously reported about a recent study demonstrating that adolescents who consume high-fructose corn syrup are putting themselves at risk of heart disease.