Today's scare du jour was just launched by the Center for Science in the Public Interest. They claim that the caramel coloring in Coke (and in dark beer and lots of other good stuff) is carcinogenic and ought to be banned. See "FDA Urged to Prohibit Carcinogenic 'Caramel Coloring'".
The claim can be summed up as follows: industrial caramel is unnatural and the product of scary-sounding processes involving scary-sounding chemicals; one of the resulting constitutive chemicals, 4-methylimidazole, has been found "in significant levels" of five brands of cola; 4-methylimidazole causes cancer in lab rodents; therefore, my Cherry Coke is a cancer hazard. Is there anything to it?
Well, sure enough there's a study of lab rats and mice that found small increases in the risk of lung cancer and leukemia that increased as doses (the rodents got the equivalent of thousands of cans of cola per day worth of 4-methylimidazole) increased. See "Toxicity and Carcinogenicity Studies of 4-Methylimidazole in F344/N Rats and B6C3F1 Mice". But something else very interesting happened along the way to a good health scare - something not mentioned by the CSPI.
It turns out that while there were small and at best equivocal indications that 4-methylimidazole might be associated with one or two rodent cancers there were big, statistically significant and dose-dependent associations between cancer prevention and 4-methylimidazole consumption. For example, compared to the rodents not given 4-methylimidazole the female rodents drinking cola by the barrel were essentially completely protected from mammary tumors as well as a host of other cancers. Overall, rodents on a cola binge experienced a greatly reduced risk of many cancers and saw some tumor rates reduced by orders of magnitudes compared to their cousin rats and mice not given 4-methylimidazole.
There was no call for research into the protective effects of caramel coloring. The great big silver lining wasn't even disclosed. Instead, the two insignificant bits of data showing a small risk of tumors in rodents were cherry picked from the forest of data and the big effect, a cancer-protective effect, was completely ignored.
I'll go out on a limb and predict that this scare, like the CSPI acrylamide in bread, chips and roasted coffee is going to give everybody cancer scare, is also headed for the dustbin of history.