Your favorite pick-me-up may be contaminated with fungi byproducts called mycotoxins, new research shows
Newsflash: Your coffee may come with more of a kick than just caffeine. Researchers from the University of Valencia analyzed over 100 coffees sold in Spain and found many tested positive for mycotoxins—a toxic metabolite produced by mold. (Check out these 11 Coffee Stats You Never Knew.)
The study, published in Food Control, confirmed the presence of a handful of different types of mycotoxins at levels ranging form 0.10 to 3.570 micrograms per kilogram. If you're thinking a byproduct of mold isn’t good for your health, you'd be right: Ingesting or inhaling too much of the metabolites can lead to mycotoxicosis, where the toxins enter the blood stream and lymphatic system and can cause a wide range of gastrointestinal, dermatological, and neurologic symptoms—including, in the most severe cases, death.
The one kind of mycotoxin that is actually regulated in Europe since it has been connected with kidney disease and urothelial tumors, ochratoxin A, measured in at six times the legal limit.
However, the researchers were quick to point out that we don’t really know whether the levels confirmed in coffee are actually high enough to be harmful. And that idea is echoed by David C. Straus, Ph.D., a professor of immunology and molecular microbiology at Texas Tech University who was not involved in the study. “Mycotoxins can be dangerous in a food substance like coffee, but it is unknown what levels are toxic in humans because it’s never been studied,” he explains. (Bacteria may not always be bad, though. Find out more in Asking for a Friend: Can I Eat Moldy Food?)
Plus, there are many different mycotoxins, which can be quite different in toxicity, Straus points out, so specific toxicity levels would have to be determined for all the types found in coffee.
Both the researchers and Straus agree it’s hard to tell if these findings should warn you off your daily fix, but both also agree further research should be done to assess the actual risk to public health.
Until then, caffeinate with caution.