Food marketers have long had a special knack for euphemism.  (If you didn’t believe me I’d offer you a Rocky Mountain oyster.)  But even as someone who has watched the food industry closely for 40 years, sometimes even I can get taken by surprise.

One such case is an innocent-sounding ingredient that appears on Coca-Cola, Pepsi, and other soft drinks: “caramel coloring.”  Now, I’ve long urged Americans to drink less soda.  It’s a nutritionally worthless beverage that provides nothing of benefit to the diet, but whose sugar, in the form of high-fructose corn syrup, promotes weight gain, obesity, diabetes, and other health problems.  Another typical soda ingredient, phosphoric acid, rots teeth.  Caffeine is a mildly addictive stimulant drug. 

One ingredient in a can of Coke or Pepsi I’ve been least concerned about is “caramel coloring.”  After all, wouldn’t that just mean the drink was colored with the kind of caramel you could make at home, by melting and browning sugar in a pan?

The truth is more complicated.  It turns out that federal regulations describe four types of caramel coloring.  And at least three of these are quite different from the confection with the similar name.  All of these do start out with some form of sugar.  One is called plain caramel.  A second can be reacted with sulfite compounds.  A third can be reacted with ammonium compounds.  And a fourth caramel coloring—the kind used in Coke and Pepsi—is reacted with both ammonium and sulfite compounds.  Both the regulations and some manufacturers’ Web sites call this form of caramel coloring Caramel IV, or less appetizingly, ammonia-sulfite process caramel.

When ammonia is used to make these caramel colorings, a number of chemical byproducts are formed.  Two of these, 2-methylimidazole and 4-methylimidazole have been shown in government studies to promote lung, liver, and thyroid tumors in laboratory rats and mice.

In a study published last month in the Journal of Agricultural and Food Chemistry, scientists at the University of California at Davis found significant levels of 4 methylimidazole in two unspecified brands of cola.  For that reason, the Center for Science in the Public Interest is today asking the Food and Drug Administration to bar the use of ammonia- and ammonia-sulfite process caramel colorings.

Considering that the purpose of this contaminated caramel coloring is purely cosmetic, we hope the FDA quickly acts to protect Americans from an unnecessary cancer risk. 

California public health officials have recently placed 4-methylimidazole on the state’s list of known carcinogens.  Because the amount of the carcinogen in the soda far exceeds what the state considers to be safe, that listing sets the stage for warning labels on Coke, Pepsi, and many other soft drinks unless the companies shift to safer colorings.  (Other foods are made with caramel colorings, but the consumption of those foods might be too small to trigger warning labels.)

Because 2- and 4-methylimidazole do not appear to be highly potent carcinogens, the 10 teaspoons of high-fructose corn in a can of cola probably poses a much greater health risk.  But if you were waiting for one more reason to give up your soda habit, you now certainly have one.