Researchers warned that regularly drinking soda could raise one's cancer risk due to a carcinogenic byproduct of caramel color.
Caramel color is a common ingredient in colas and other dark-colored soft drinks, and the manufacturing process of some forms of this type of food dye involves the possible carcinogen 4-methylimidazole (4-MEI), Johns Hopkins Bloomberg School of Public Health reported. Data has suggested that between 44 and 58 percent of people over the age of six consume at least one can of soda per day.
"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, PhD, senior author of the study and director of the Food Production and Public Health Program at the CLF and an assistant professor at the Johns Hopkins Bloomberg School of Public Health. "This unnecessary exposure poses a threat to public health and raises questions about the continued use of caramel coloring in soda."
In 2013 and early 2014, Consumer Reports partnered with the CLF to analyze 4-MEI concentrations in 110 soft drink samples collected in metropolitan areas of New York and California. The researchers then looked at consumption data from the National Health and Nutrition Examination Survey (NHANES) to estimate the risk imposed on the general public.
"This new analysis underscores our belief that people consume significant amounts of soda that unnecessarily elevate their risk of cancer over the course of a lifetime," says Urvashi Rangan, PhD, executive director for Consumer Reports' Food Safety and Sustainability Center. "We believe beverage makers and the government should take the steps needed to protect public health. California has already taken an important step by setting a threshold for prompting Prop 65 labeling based on daily 4-MEI exposure from a food or beverage, such as a soda. This study sought to answer a critical question: How much soda do American consumers drink on average?"
While the study was not large enough to recommend certain soda brands over others, it did find 4-MEI levels varied significantly across the samples, even for the same type of beverage.
"For example, for diet colas, certain samples had higher or more variable levels of the compound, while other samples had very low concentrations," said Tyler Smith, lead author of the study and a program officer with the CLF.
There is currently no federal limit for 4-MEI in food or beverages, but Consumer Reports petitioned the Food and Drug Administration to create these limits last year. The findings were also shared with the California Attorney General's office, which enforces the state's Proposition 65 law that works to reduce the population's consumption of potentially toxic chemicals. The law ensures that any products containing a certain amount of 4-MEI come with a health-warning label. The study showed there were generally higher levels of the potential carcinogen in New York-based samples when compared to those purchased in California.
"Our study also found that some of the soft drink products sold in California that we sampled had lower levels of 4-MEI than the samples we looked at of the same beverages sold outside the state, particularly in our earlier rounds of testing. It appears that regulations such as California's Proposition 65 may be effective at reducing exposure to 4-MEI from soft drinks, and that beverages can be manufactured in ways that produce less 4-MEI," Nachman said. "An FDA intervention, such as determining maximum levels for 4-MEI in beverages, could be a valuable approach to reducing excess cancer risk attributable to 4-MEI exposure in the U.S. population."
The results were published in a recent edition of the journal PLOS One.
