Soft Drinks May Contain Cancer-Causing Ingredient
WASHINGTON, February 20, 2015—Caramel color, a popular ingredient in many dark sodas and soft drinks, may pose a cancer risk to consumers, according to a market-based study published online Wednesday in the journal PLoS One.
“Soft drink consumers are being exposed to an avoidable and unnecessary cancer risk from an ingredient that is being added to these beverages simply for aesthetic purposes,” said Keeve Nachman, director of the Food Production and Public Health Program at the Center for a Livable Future (CLF) and senior author of the study. “This unnecessary exposure poses a threat to public health and raises questions about the continued use of caramel coloring in soda.”
Caramel color, contained in many types of cola, iced teas and root beers, is produced with ammonium compounds, which can result in the formation of 4-methylimidazole (4-MEI), a possible human carcinogen.
A 2007 study on lab mice and rats performed by the U.S. National Toxicology Program (NTP) resulted in “clear evidence of carcinogenic activity” in the lungs of mice of both sexes, as well as “equivocal evidence of carcinogenic activity in female rats” which saw increased risk of leukemia.
As a result of the 2007 study, 4-MEI was classified as Group 2B, “possibly carcinogenic to humans,” by the International Agency for Research on Cancer. California listed 4-MEI as a carcinogen in 2011 under the Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65), which requires manufacturers to include a warning label if the product exceeds a no significant risk level (NSRL). The NSLR for 4-MEI is set at 29 ?g per day. In response, soft drink manufacturers stated that they would lower 4-MEI levels in their products.
Researchers worked in two phases. First, they tested 110 samples of 12 brands of soft drinks purchased in California, where Proposition 65 applies, and New York, where there is no similar law requiring manufacturers to warn consumers of the levels of 4-MEI in their products.
Malta Goya (915.8 to 963.3?g/L) and Pepsi had the highest levels of 4-MEI and Coca-cola had the lowest (9.5 to 11.7?g/L). It also found that, with the exception of Malta Goya which was high everywhere, most of the drinks that were purchased in California had lower 4-MEI concentrations than those purchased in New York. See full results here.
“This supports the notion that Proposition 65 and, potentially, other state-level interventions can incentivize manufacturers to reduce foodborne chemical exposures and associated risks among consumers,” stated the authors Wednesday.
In the second phase of the study, published Wednesday, researchers used the results from the first phase and data from the National Health and Nutrition Examination Survey to estimate the risk of cancer associated with soda consumption in 6- to 64-year-olds. According to the study, between 76 and 5,011 cancer cases in the U.S. in the next 70 years will be caused by exposure to 4-MEI alone.
The researchers revealed that the study had limitations. Even though other foods like sauces, gravies, roasted meats and baked goods as well as drinks like blended whiskey and beer also contain 4-MEI, the study assumed no other 4-MEI exposure. Researchers also assumed that subjects drank only one kind of soda and not any of the others.
There are currently no federal limits regarding 4-MEI, which is classified as a food additive by the Food and Drug Administration (FDA). Given the question raised recently, FDA states,
“To ensure that the use of caramel coloring in food continues to be safe, FDA is currently reviewing all available data on the safety of 4-MEI and is reassessing potential consumer exposure to 4-MEI from the use of Class III and Class IV caramel coloring in food products… However, in the interim, FDA is not recommending that consumers change their diets because of concerns about 4-MEI.”
Many disagree, including the study authors. They argue that caramel coloring and 4-MEI in soft drinks is an unnecessary aesthetic ingredient that could pose an avoidable risk of cancer.