According to the Center for Science in the Public Interest (CSPI), the compounds in the caramel coloring in many soft drinks has been shown to cause lung, liver, and thyroid cancer in lab mice and rats. Because of these findings, the CSPI has called on the Food and Drug Administration (FDA) to ban the use of caramel coloring. The guilty ingredients are 2-methylimidazole (2-MEI) and 4-methylimidazole (4-MEI). These compounds form when sugar is mixed with ammonia and sulfites. It may not effect the flavor, but it creates the caramel, or brown color.
This year the state of California determined that 4-MEI qualified as a carcinogen. Because of this ruling, companies using that coloring compound would be required to print cancer warnings on their packages or reformulate their products. Further, the CSPI said their recent lab studies found that the 4-MEI levels in many 12-ounce sodas exceeded the 29 microgram limit set by California law.
“The body of science about 4-MEI in foods or beverages does not support the erroneous allegations that CSPI would like the public to believe,” said a Coca-Cola representative. “The 4-MEI levels in our products pose no health or safety risks.”
Regardless of the debate, Coca-Cola has decided to change its manufacturing process rather than print cancer warnings on their drinks.