4-methylimidazole (4-MEI) is a carcinogen in the caramel coloring used in many foods, especially soft drinks. In 2011, California listed 4-MEI as a known carcinogen and determined safe levels in drinking water, after the US National Toxicology Program (NTP) conducted tests of 4-MEI in lab animals. The NTP found “clear evidence” that 4-MEI increased incidence of cancer in rats, while noting that no human studies have been done to date.
Researchers at Johns Hopkins this week released a paper in the prestigious journal PLOS ONE extrapolating known quantities of 4-MEI in soft drinks into cancer incidence predictions. The analysis shows that with current soft drink consumption rates in the US, up to 5,000 cases of new cancers could be caused by the 4-MEI in one brand of soft drink alone in the next 70 years.
There are currently no regulations in US on how much 4-MEI can be included in foods, however in California, if a food contains more than 29 micrograms (mcg) of 4-MEI, the product must be labeled as containing a carcinogen. At this level, the cancer risk is one per 100,000 people exposed. A 2013 study found that 4-MEI levels in common soft drinks ranged from 3.4 to 352.4 mcgs per 12-ounce soda. Malta Goya had the highest amounts, while Diet Coke had the lowest. For Malta Goya drinkers, they are consuming over 10 times the amount of 4-MEI considered an acceptable cancer risk. The Johns Hopkins researchers noted that “4-MEI concentrations varied considerably by soda and state/area of purchase, but were generally consistent across lots of the same beverage purchased in the same state/area.”
Since caramel coloring adds nothing to flavor and is often not even seen by the consumer if drinking from an aluminum can, many manufacturers are looking for safer alternatives in light of the public and California concerns. 4-MEI is not even an added ingredient of caramel coloring, but a byproduct formed during the manufacturing process. The FDA still lists caramel color as “Generally Recognized As Safe” despite the research data. In 2012, the Center for Science in the Public Interest petitioned the FDA to prohibit Class III and Class IV caramel colors, the most common types.
In 2007, a controversial study by the University of Southampton in the UK found that 6 artificial colors were linked to hyperactivity in children. As a result, European food manufacturers have made more progress than their US counterparts in replacing artificial colors with natural colors. Stefan Hake, CEO of GNT USA in New York noted that “all the (Southampton) colors listed can be replaced with fruit- and vegetable-based colors.” Several natural food colors such as tumeric and carotenoids ironically have anticancer properties.