- A California judge ruled this week that Starbucks and other businesses that sell coffee will have to include warnings saying it contains a substance that could cause cancer.
- Coffee contains acrylamide, a chemical byproduct of roasting coffee beans.
- We have reason to think that acrylamide, in high doses, can cause cancer and could be toxic.
- But there’s no evidence that we should worry about the amount of acrylamide in coffee. If anything, coffee seems connected to a lower risk of cancer.
When coffee beans are picked and removed from the fruit they’re inside, they’re a pale colour.
It’s only after they’re roasted that they take on a dark or light shade of brown and develop that wonderful aroma that we associate with comfort and feeling alert.
But that cooking process creates byproducts. One of the chemicals formed when coffee is roasted is acrylamide, a substance discovered in 2002 by Swedish scientists.
But whether there’s enough of it in coffee to be concerned about is a different question.
Because of the presence of acrylamide in coffee, the Council for Education and Research on Toxics filed a lawsuit in 2010 in California against businesses like Starbucks that sell coffee, asking that they be required to post warnings saying coffee contains cancer-causing chemicals.
On Wednesday, a California judge ruled in favour of the council, meaning Starbucks and other companies will indeed be required to post those warnings (Starbucks had already agreed to post some, but they may now need to be featured more prominently). Whether the companies have financial penalties has not yet been decided.
That said, there’s extensive scientific research on coffee, most of which indicates that, if anything, coffee consumption is associated with a lower risk of several types of cancer.
When it comes to acrylamide, the dose makes the poison
Pump enough of any chemical into an animal or person, and you’ll eventually get to a point where that substance is dangerous.
But these situations aren’t always reflective of the real world.
In the case of acrylamide, we know that being exposed to too much of it is dangerous.
Data suggests that in large quantities, acrylamide is carcinogenic to some animals. Animal studies have found that putting acrylamide in drinking water can cause cancer in rats and mice. But the doses they consumed in those studies are 1,000 to 100,000 times what people get through their diet.
Industrial accidents in which people have inhaled large quantities of acrylamide indicate it can harm humans too. It’s also one of the many chemicals in cigarette smoke, though in higher amounts than produced in coffee-making.
So far, there’s no evidence that the amount of acrylamide in coffee is dangerous. Plus, it can’t be avoided.
Acrylamide naturally forms when plants and grains are cooked at high temperatures. It’s created in a process known as the Maillard reaction, in which high heat transforms sugars and amino acids in ways that change flavours and tend to brown food.
When potatoes, bread, biscuits, or coffee are heated, acrylamide forms. It’s present in about one-third of the calories the average American or European consumes.
The way humans metabolize the chemical is different from how animals do. And so far, studies haven’t found any harmful connection between various common cancers and consuming foods containing acrylamide.
A toxic situation
Previous lawsuits by the Council for Education and Research on Toxics have led potato-chip makers to say they’d cut acrylamide levels in their products and pay a hefty fine.
According to The Associated Press, the law that lets groups sue companies over claims that they expose people to chemicals has helped eliminate some dangerous chemicals but has also been “criticised for leading to quick settlement shakedowns.”
But changing the coffee-roasting process isn’t really an option, and it’s always going to create byproducts like acrylamide.
There’s still no good reason to believe that drinking coffee is dangerous. Caffeine, also found in coffee, can be deadly at high doses – but that doesn’t mean it’s all bad.
The International Agency for Research on Cancer removed coffee from its “possible carcinogen” list in 2016 (though acrylamide is still on the “probable carcinogen” one).
At least one major review of studies found that the more coffee that people drink, the lower their risk of liver cirrhosis or liver cancer. And a review of more than 200 studies found that people who drank three or four cups of coffee a day were 19% less likely to die from cardiovascular disease. Heavy coffee drinkers have an 18% reduced risk of cancer overall, according to one large study, and some data indicates that coffee drinkers may be less likely to have oral or pharyngeal cancer or advanced prostate cancer.
There are other potential health benefits of coffee too.
While it’s not a good idea to inhale acrylamide from an industrial site, there is no reason to think the amount in coffee is dangerous. And putting danger labels on everything could make people less likely to pay attention to the ones that really do matter, like those on cigarettes.
The bottom line, for now, is that coffee retailers in California will have to post warnings. But that doesn’t mean there’s evidence that coffee itself is risky.