In contrast to the caramel one might make at home by melting sugar in a saucepan, the artificial brown colouring in colas and some other products is made by reacting sugars with ammonia and sulphites under high pressure and temperatures.
Chemical reactions result in the formation of 2-methylimidazole and 4-methylimidazole, which in government-conducted studies caused lung, liver or thyroid cancer or leukaemia in laboratory mice or rats.
The National Toxicology Program, the division of the National Institute of Environmental Health Sciences that conducted the animal studies, said that there’s “clear evidence” that both 2-MI and 4-MI are animal carcinogens. Chemicals that cause cancer in animals are considered to pose cancer threats to humans. Researchers at the University of California, Davis, found significant levels of 4-MI in five brands of cola.
“Carcinogenic colourings have no place in the food supply, especially considering that their only function is a cosmetic one,” said CSPI executive director Michael F Jacobson. “The FDA should act quickly to revoke its approval of caramel colourings made with ammonia.”
Federal regulations distinguish among four types of caramel colouring, two of which are produced with ammonia and two without it. CSPI wants the Food and Drug Administration to prohibit the two made with ammonia. The type used in colas and other dark soft drinks is known as Caramel IV, or ammonia sulphite process caramel. Caramel III, which is produced with ammonia but not sulphites, is sometimes used in beer, soy sauce and other foods.
Five prominent experts on animal carcinogenesis, including several who have worked at the National Toxicology Program, joined CSPI in calling on the FDA to bar the use of caramel colourings made with an ammonia process.
“The American public shouldn’t be exposed to any cancer risk whatsoever as a result of consuming such chemicals, especially when they serve a non-essential, cosmetic purpose,” the scientists wrote in a letter to FDA Commissioner Margaret Hamburg.
CSPI also says the phrase ‘caramel colouring’ is misleading when used to describe colourings made with ammonia or sulphite. The terms ‘ammonia process caramel’ or ‘ammonia sulphite process caramel’ would be more accurate, and companies shouldn’t be allowed to label any products that contain such colourings as ‘natural’, according to the group.
“Most people would interpret ‘caramel colouring’ to mean ‘coloured with caramel’, but this particular ingredient has little in common with ordinary caramel or caramel candy,” Jacobson said. “It’s a concentrated dark brown mixture of chemicals that simply doesn’t occur in nature. Regular caramel isn’t healthful, but at least it’s not tainted with carcinogens.”
In a little-noticed regulatory proceeding in California, state health officials have added 4-MI to the state’s list of ‘chemicals known to the state to cause cancer’.
Under that state’s Proposition 65, foods or other products containing more than certain levels of cancer-causing chemicals must carry warning labels. For 4-MI, that level is 16 micrograms per person per day from an individual product. Popular brands of cola contain about 200 micrograms of 4-MI per 20oz bottle, and many people – especially teenaged boys – consume more than that each day. If California’s regulation is finalised, Coke, Pepsi and other soft drinks would be required to bear a cancer warning label.
To put the risk from caramel colouring in context, CSPI says the 10 teaspoons of obesity-causing sugars in a non-diet can of soda presents a greater health risk than the ammonia sulphite process caramel. But the levels of 4-MI in the tested colas still may be causing thousands of cancers in the US population.
Separate from the risk due to caramel colouring, CSPI has been urging the FDA to ban synthetic food colourings, such as Yellow 5 and Red 40. Those dyes cause hyperactivity and other behavioural problems in children, and Red 3 and Yellows 5 and 6 pose cancer risks, according to CSPI. The FDA is holding a Food Advisory Committee review of that issue on 30-31 March.
Over the years, CSPI’s efforts have resulted in reductions in the use of labelling requirements or limits on Violet No. 1, sodium nitrite and sodium nitrate, sulphites, partially hydrogenated vegetable oils, salt and olestra.
Source: Center for Science in the Public Interest
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