“Dozens of studies suggest that coffee drinkers live longer, have healthier hearts and are happier.”
— William Murray, president
National Coffee Association, USA
“At the moment, there is no strong evidence linking acrylamide and cancer.”
— Cancer Research UK
If you’re like most Americans, your day might just begin around a Keurig, in line at a Tim Horton’s, or just at the office coffee machine, waiting for the a.m. infusion of caffeine. Some 64% of American adults report that they drink coffee every day, and the average American adult consumes 3.1 cups of the brew daily. Despite that, the International Coffee Organization reports that the Italians, French, Swiss, Germans, Swedes, and Finns all consume more coffee per year than Americans do.
If you frequent coffee establishments that also do business in California, like Starbucks, or Dunkin Donuts, you may have noticed a curious and concerning warning label appear on your coffee cup in 2018, and disappear again about a year later. First mandated two years ago under an application of the California Safe Drinking Water and Toxic Enforcement Act of 1986, the link between coffee and cancer was determined the following year to be too tenuous, and the warning requirement was removed. The tale of how the warning came to be involves both a court case and the always difficult application of animal research to human danger.
Studies have, for years, shown that baking and frying certain foods, including the roasting of coffee beans, causes the production of chemical known as acrylimide. Studies have also shown that some level of acrylimide can be safely broken down by the human body, and that high levels of it can be carcinogenic. According to a 2008 study by scientists at the Harvard School of Public Health, more than a third of the calories consumed by Americans and Europeans contain some low levels of acrylimide. But other studies, such as a 2012 study from the National Toxicology Program, show that acrylimide causes cancer in lab mice.
These studies led to a lawsuit filed in California by the Council for Education & Research on Toxics (CERT), a nonprofit founded in Long Beach in 2003. CERT sued more than 90 manufacturers and distributors of coffee as well as a blend of retail establishments like Starbucks, Dunkin, WalMart and Costco. Citing the 1986 California labeling law, CERT claimed that the coffee those establishments were doling out every day was toxic and needed to be labeled as such.
The lawsuit percolated along for several years (it was a dry process) before a judge ordered that the retailers put the warning on their cups in 2018. But that order soon got roasted by a new crop of research. It turns out that even though one-third of the calories we eat contain acrylimide, we only ingest 0.5 mcg/kg. But the mice were given as much as 750 times that when they were tested. It was the equivalent of those mice drinking 2,250 cups of coffee a day. I’m not a coffee drinker, but I’m going to guess that, on balance, that much coffee will likely kill you.
California authorities thought so, too, and concluded that mandating the warning had a bad aroma. They rescinded the warning order in 2019, and it disappeared from coffee cups just as quickly as it had appeared. And based on those new conclusions, the judge in the California case granted the defendant’s motion to dismiss last week, bringing the decade-long matter to an end. The news certainly cause a stir. Even the French press reported on it.
Separating the wheat from the chaff on this kind of research can be hard. UC Davis professor Alyson Mitchell was quoted in news about the dismissal as saying that we “really don’t know” the exact impact of acrylimide consumption in humans, nor the precise level where it becomes dangerous. But whether it’s acrylimide, aspartame, margarine, or even sugar, the application of laboratory animal studies to humans can be complicated and difficult. As one 2015 study in the Journal of Cancer noted, “rodents’ short lifespans cannot give us information of the long-term safety” of foods.
So, enjoy your morning coffee, but remember the words of the Roman dramatist Plautus, “moderation in all things is the best policy.”