Death by Coffee? Enter Sweden’s “First Clinical Trial”

Today just about anyone can run up to McDonald’s and order a coffee for $1 in order to feel like a human again.  There’s a reason why those “But first, coffee” shirts have become so popular. However, this was not the case in 18th century Sweden.  Back in the day, really only the wealthy drank the strong, dark colored beverage–much to the dismay of the King. In 1756 King Adolf Frederick imposed a tax on coffee imports to deter the public from drinking the beverage. When that didn’t have the effect he wanted, he banned coffee in its entirety later that same year. Even with the ban and mass propaganda condemning the act of drinking coffee, consumption still continued through bootlegging (I’m feeling major parallels to Prohibition here). 

Fast forward a bit, Adolf is now off the throne and his son, King Gustav III has taken his place. Like his father, Gustav was a staunch believer in the notion that coffee was detrimental to his subjects, and concocted a scientific experiment to prove it (which is now referred to by some as Sweden’s first clinical trial). He ordered that two identical twins, both of whom had been condemned to death for crimes, become his test subjects.  The twins agreed to the conditions of one drinking three pots of coffee per day and the other drinking three pots of tea per day for the rest of their lives. In exchange for their participation, their sentences were commuted to life in prison. The goal was for two royally appointed physicians to observe the subjects and compare the health effects of the drinks.  Interestingly, both of the doctors supervising the experiment died before their subjects, as well as the King himself (who was assassinated). According to records, the tea drinker passed away first at the age of 83. Honestly, in my eyes if you made it to 83 in 18th century Sweden I would say that you did pretty well. After the experiment, the government tried a few more times to ban coffee in Sweden before finally giving up in the 1820s.  Today, its very evident how much the Swedes love this caffeinated drink as Sweden has one of the highest rates of coffee consumption per capita in the world.

Obviously there were many flaws with this experiment (where were the controls? Was a “pot” a consistent form of measurement?). Nevertheless, everything comes from somewhere and the Swedish King’s attempt to prove coffee to be poisonous is an interesting case study of early developments in the modern clinical trial.

Sources/Where to head to learn more:

This King Hated Coffee So Much He Tried to Kill Someone With It, Erin Blakemore (History.com)
https://www.history.com/news/this-king-hated-coffee-so-much-he-tried-to-kill-someone-with-it

Gustav III of Sweden’s Coffee Experiment
https://en.wikipedia.org/wiki/Gustav_III_of_Sweden%27s_coffee_experiment

Gustav III’s risk assessment on coffee consumption; A medical history report, Reza Afshari (Avicenna Journal of Phytomedicine)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5355814/