The folks at Center for Science in the Public Interest (CSPI) have apparently run out of poisons to scare us with because they are now recycling some oldies. Their scare du jour is called 4-methylimidazole (4-MEI). Yawn.
Old, like in 1951--the earliest paper I could find in which the compound was studied for toxicity in rats. The rats are most likely no longer alive, but it wasn't because of the 4-MEI. Nothing happened to them during the experiment.
In fact when the authors tried to find the minimum amount of 4-MEI required to show toxicity, it was estimated to be 5 grams per day per rat, a crazy high number. Applied to humans, that comes to 700 grams per day. To put this in perspective, this is weight of 3 boxes of Kraft macaroni and cheese before cooking. That's how much chemical you would have to eat. It's not clear whether that much mac and cheese would also kill you.
Having worked (and played) with chemicals for 30 years, I developed a pretty good idea which ones are bad (e.g. getting one drop on the back of your lab glove and dying) and ones that you could pretty much bake into a creme brÃ»lÃ©e without anyone noticing much of a difference. 4-MEI is quite a bit closer to the latter.
Which isn't all that unexpected, since it is one of components of caramel coloring, which has been used in a variety of food and drinks since before the Civil War. It gives color and flavor to soda, potato chips, beer, ice cream and whiskey to name a few. Doesn't really sound like much of a poison.
So if they can't convince people that a can of Pepsi is going to make you take an immediate dirt nap, the old cancer scam is a fine substitute. Cancer is really scary. And we all know from watching TV celebrities that we are just swimming in a vast ocean of carcinogens as a result of living in modern times. That explains why cancer rates are dropping every year! Wait a minute. No, it doesn't.
Here's how most things get labeled carcinogens: Rats or mice get fed ridiculous amounts of a chemical for their lifetime, and are then examined for tumors. Some of them get tumors. What this has to do with human health in not obvious. Does this chemical really cause cancer? The answer is "who knows?" These experiments have so little to do with mimicking a real life situation that they are essentially worthless.
This is not to say that there aren't real carcinogenic chemicals. Of course there are. All chemists have worked with them at one time or another and you have to be really careful. But this ain't one of them. The "evidence" of human carcinogenicity of 4-MEI is nonexistent. Yet that doesn't stop CSPI issuing the headline "Lab Tests Find Carcinogen in Regular and Diet Coke and Pepsi" today. Please.
While these guys are busy measuring barely-detectable amounts of chemicals in this and that, they are doing us all a disservice by taking attention from real risks, like smoking, drunk driving, obesity and The Real Housewives of New Jersey. Give us a break, guys. We have enough to worry about.
4-Methylimidazole Warning # 407 (Medical Progress Today)