In a letter to the U.S. Food and Drug Administration, the consumer watchdog group Center for Science in the Public Interest called on officials to ban the use of caramel coloring in popular soft drinks, citing a possible cancer risk.

This isn’t the first time that CSPI has targeted the food additive that gives colas, including Coke and Pepsi, their familiar brown color. The organization first petitioned the FDA on the matter in 2011, noting that 2-methylimidazole and 4-methylimidazole, which form when sugar is mixed with ammonia and sulfites to create caramel coloring, had been shown to cause lung, liver and thyroid cancer in mice and rats.

In a letter written Monday to FDA Commissioner Dr. Margaret Hamburg, CSPI executive director Michael F. Jacobson described recent lab analyses that showed 4-methylimidazole, or 4-MI, levels in 12-ounce servings of soda that exceeded the 29 microgram limit recommended by the state of California by nearly five times. The average 4-MI content for samples of regular and diet Coke, Pepsi and Dr. Pepper and Whole Foods 365 cola was 138 micrograms. (Some samples of Dr. Pepper and the Whole Foods cola sample had far lower amounts of 4-MI, however.)

The CSPI letter said that the average level of 4-MI indicated a lifetime risk of cancer of five out of 100,000 people in the population -- and perhaps more when people who do not drink sodas are left out of the calculation.


“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. The reality it quite different,” said Jacobson, in a statement released by the organization Monday.

Food industry groups pooh-poohed the complaint. On Monday, the American Beverage Association called the CSPI news release a “scare tactic,” saying in a statement that “findings of regulatory agencies worldwide, including the U.S. Food and Drug Administration, European Food Safety Authority and Health Canada, consider caramel coloring safe for use in foods and beverages.”

In 2011 an article on Time magazine’s Healthland blog quoted one scientist who said that a human being would have to drink more than 1,000 sodas a day to achieve exposure to 2-MI and 4-MI that had been shown to cause cancer in the lab animals.

Jacobson’s letter to the FDA questioned whether any amount of caramel coloring was appropriate. “The caramel coloring added to soft drinks serves a totally cosmetic function,” it said. “We suspect that most consumers would prefer a clear beverage without an unnecessary carcinogen over a dark-brown beverage with a carcinogen.”


But the far bigger worry for soda drinkers remains high-fructose corn syrup and other sugars used in soft drinks. “Soda drinkers are much more likely than non-soda drinkers to develop weight gain, obesity, diabetes and other health problems,” CSPI’s statement explained.

In 2007, The Los Angeles Times reported on the potential cancer risk from sweeteners like aspartame. The truly health-conscious will probably want to avoid sodas altogether -- whether they’re made with caramel coloring, artificial sweeteners or loads of sugar or not.

[Updated at 11:25 a.m., March 6: Ben Sheidler, a spokesman forCoca-Cola, wrote to Booster Shots on Tuesday with a response to the CSPI report: “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,” he wrote. “The 4-MEI levels in our products pose no health or safety risks. Outside of California, no regulatory agency concerned with protecting the public’s health has stated that 4-MEI is a human carcinogen. The caramel color in all of our ingredients has been, is and always will be safe.”]