August 25th, 2016
A study published today in Scientific Reports says that your coffee addiction may be genetic. The researchers surveyed and tested people from Italy and the Netherlands, and found that those who carry a specific variant of the gene “PDSS2” tend to consume about one cup of coffee fewer per day. The gene variant apparently slows down the body’s metabolism of caffeine—making caffeine linger in the blood for longer and giving carriers of this gene variant a longer-lasting hit per cup.
The authors say that coffee has been linked to protective effects on “cardiovascular diseases, hypertension, Alzheimer’s and Parkinson’s diseases, type 2 diabetes, some types of cancer, and hearing functions.” On the (unsurprising) down side, it may also be linked to sleep disturbances. So studying exactly how and why coffee impacts people differently could provide more information on fighting those diseases and conditions as well.
We should be careful, though, to not myopically assume that addictions, whether to caffeine or other drugs, are primarily genetic.
As Influence columnist Stanton Peele has written, genetic understandings of mental illness and addiction tend to obscure the ways that both are impacted by environmental and situational factors. Plus, as Ethan Watters writes in Crazy Like Us: The Globalization of the American Psyche, studies have shown that “those who adopted biomedical/genetic beliefs about mental disorders were the same people who wanted less contact with the mentally ill and thought of them as more dangerous and unpredictable.” In truth, mental illnesses and addictions “have never been the same the world over (either in prevalence or in form) but are inevitably sparked and shaped by the ethos of particular times and places.”
The importance of social factors can be seen in the coffee study itself: The genetic effect existed in both Italy and the Netherlands, but was stronger in Italy.
The researchers posit an explanation based on coffee preferences in the two locations. While Italians prefer small shots of espresso or moka, the Dutch tend to drink larger cups of filtered coffee. Both types of coffee actually have similar concentrations of caffeine, so coffee-drinkers in the Netherlands are getting about three times as much caffeine per cup as Italians. Researchers posit that the PDSS2 gene may not be as active at higher levels of caffeine consumption.
One other note: One of the authors named in the study works for the Italian coffee company Illy.