Dark-Colored Sodas May Have Toxic Backwash, Or Not
Mar09

Dark-Colored Sodas May Have Toxic Backwash, Or Not

The Center for Science in the Public Interest (CSPI) has made a claim that “caramel coloring” used to improve the eye appeal of colas and other dark-colored soft drinks contains the carcinogenic by-products 2-methylimidazole and 4-methylimidazole (shown) and thus might be a cause of thousands of cancers in the U.S. The nonprofit consumer advocacy organization made its announcement via a regulatory petition filed with the Food & Drug Administration on Feb. 16. Besides being used in colas, the artificial coloring, which can range from yellowish to black, is used in some baked goods, precooked meats, soy and Worcestershire sauces, chocolate-flavored products, and even whiskey and beer. It’s typically made by pyrolyzing sugar with the aid of ammonium and/or sulfite compounds, a process that forms many derivative chemicals. This browning process is similar to, but distinct from, the Maillard reaction between a sugar and an amino acid. CSPI wants FDA to revoke regulations allowing the types of caramel coloring made using ammonium compounds, which contain the imidazoles. “Carcinogenic colorings have no place in the food supply, especially considering that their only function is a cosmetic one,” CSPI Executive Director Michael F. Jacobson said when announcing the petition. CSPI is invoking the Delaney Clause, an amendment to the Food, Drugs, & Cosmetic Act of 1938, to state that FDA is obligated to ban caramel coloring--the clause stipulates that FDA “shall not approve for use in food any chemical additive found to induce cancer in man, or, after tests, found to induce cancer in animals.” The issue of the toxicity or nontoxicity and possible regulatory control of the imidazole compounds has been bouncing around for a few years. CSPI based its petition on a pair of 2007 studies (1 and 2) published by the National Toxicology Program (NTP), a unit of the National Institute of Environmental Health Sciences. The studies conclude that 2- and 4-methylimidazole, compounds known to be in cigarette smoke, caused cancer in rats and mice. But NTP has not listed the imidazole compounds as being carcinogenic. CSPI also cites a paper by researchers at the University of California, Davis, who detected 4-methylimidazole in five brands of cola. The UC Davis researchers extrapolated their data to the NTP studies and concluded that “the amounts ingested from these beverages may not be significant.” Nonetheless, CSPI’s press announcement suggests that the amount of the compound in colas is large enough to be cause for concern, although the amount in soy sauce and other products is likely small enough to not be a problem. Caramel coloring is largely unregulated in the U.S., but California state health officials have added 4-methylimidazole to the state’s list...

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