A group of plaintiffs—the California League of Food Processors, the American Beverage Association, Grocery Manufacturers Association, and the National Coffee Association—filed a lawsuit against the California Office of Environmental Health Hazard Assessment (OEHHA) for its wrongful listing of 4-methylimidazole (4-MEI) under Proposition 65. On Jan. 7, 2011, based on a technical report from the National Toxicology Program (NTP), OEHHA listed the compound as a carcinogen. Nevertheless, NTP does not identify 4-MEI as even “reasonably anticipated to be a human carcinogen.”
4-MEI is ubiquitous in the food supply and is found in trace amounts as a result of heating certain foods, such as caramel colors. There are four classes of caramel colors each used for different purposes by the food industry. None of the caramel colors is genotoxic. Caramel III and IV, both of which do contain 4-MEI, have been tested for rodent toxicity and have not been found to be carcinogenic. Furthermore, on March 8, 2011, the European Food Safety Authority’s Panel on Food Additives and Nutrient Sources added to Food released its report that assessed the safety of a group of caramel colors authorized for use in food in the European Union. Based on all available data, the Panel concluded that these caramel colors are neither genotoxic, nor carcinogenic and that there is no evidence of any adverse effects on human reproduction or for the developing child.
So, let’s be clear. There is no scientific evidence that 4-MEI causes cancer in humans. The NTP report describes two studies using rodent models—one study was conducted using male and female B6C3F1 mice; the second study used male and female F344/N rats. Mice were fed a “low dose” of approximately 40 mg per kg per day; however, there was no significant increase in the potentially relevant tumors (benign and malignant combined) at this dose. Even so, this dose is the equivalent of more than 18,000 12-oz cans of cola per day every day for the lifetime of a 60 kg (132 lb) woman. The lowest dose that produced any increase in malignant tumors in mice was 170 mg per kg per day, the human equivalent of over 80,000 cans per day.
But of greater interest are the species differences that were noted in the report. 4-MEI consumption was protective against tumors in rats. Nevertheless, OEHHA ignored the rat study, selecting instead to focus solely on the data from the mouse study.
Is this how public policy should be set? Should a regulatory agency be allowed to selectively choose data or studies? Should the public be concerned when a regulatory agency declares a potential health risk when the animal data are conflicting and there are no human data? What is the “risk/benefit” calculus that balances the public interest and public policy?