Caramel Coloring Contains a Likely Carcinogen

While you may not have heard of 4MeI (4-Methylimidazole), you have almost certainly been eating and drinking it. A component of caramel coloring, 4MeI is the most common food-coloring chemical in the world. Most notably, it helps gives cola its signature brownish color. Over the years, a number of public health advocates and consumer groups have expressed concern about 4MeI’s safety because animal studies have repeatedly shown it causes cancer (that is, it’s carcinogenic).

Animal studies are usually not sufficient to designate a chemical as a human carcinogen and thus ban it or phase it out. But the animal data on 4MeI is compelling and based on these the International Agency for Research on Cancer—the world’s most authoritative body on carcinogens–designates 4MeI as a “possible human carcinogen.” That’s the strongest designation allowed without human studies.

Evidence in people is typically the critical part of earning the label “carcinogen.” Yet there are no human studies of 4MeI–it bears repeating, the most common food-coloring chemical in the world.

Carcinogens in a Can? (Or Bag, Box, Bottle….)

Scientists at Consumer Reports recently determined a safety threshold of 3 micrograms of 4MeI per serving. All popular cola brands, iced teas and other brown soft drinks–regular and diet—go over that amount in a single can. Some drinks exceed it by as much as 100 times. Besides soft drinks, food manufacturers use 4MeI in coffee, bread, snack food, beer and soy sauce.

Cigarette smoking, obesity and sedentary lifestyle are the major causes of cancer. Still, cancer risks from other sources should be more transparent, especially those in what we eat and drink. Furthermore, manufacturers and regulatory agencies should enact stricter guidelines to test safety and better mechanisms to appropriately communicate risks to consumers.

February 7 editing correction: “probable human carcinogen” changed to “possible human carcinogen.”

One Response to “Caramel Coloring Contains a Likely Carcinogen”

  1. Theo

    While the attempt to popularize scientific research is commendable, the author’s opinion appears to be on the extreme side of the spectrum and uses the most stringent approach that has not been subject to debate in the research community nor has it been implemented or accepted anywhere.

    The current strictest US regulations on 4Mel were passed in California which consider that consumption of up to 29 ug per day poses “no significant risk level”. The author’s acceptance of a level which is an order of magnitude lower based on unnamed Consumer Reports “experts”, without any peer review or debate over their recommendations is therefore dubious.

    Furthermore I found no basis to the statement that studies have “REPEATEDLY” shown 4MeI to cause cancer. I haven’t performed an extensive search however a quick pubmed search for “4-Methylimidazole” found that the 2007 NTP study is the only paper that analysed long term effects of its ingestion. Other studies evaluated shorter term effects.

    As to the 4MeI: it is a byproduct of fermentation, browning such as roasting or grilling of foods in certain conditions and smoking. It is therefore found in many basic food staples that were subject to these procedures including meats, coffee, beers and some of the caramel colorants which are prepared in ammonia based processes.

    Short term animal studies that used doses normally found in food colorants concluded those to be safe.

    The 2007 NTP study used mega-doses of 4Mel (on the order of drinking of tens of thousands of cans of soda a day for a human equivalent) and reported an increase in some benign conditions and benign tumors as well as lung cancer in mice. At the same time they found no evidence of an increase of lung cancer in rats however there was a form of leukemia which was found to have increased in female rats but not in male rats nor in male or female mice).
    Interestingly the same study reportedly found a DECREASE in breast cancer and other tumors in rats treated with those large doses of 4Mel.

    There is no doubt that more research can be performed on the subject however misleading statements are noncontributory and can backfire.


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