Some people can swill coffee all day and all night and still hit the pillow with a thud. For others, a cuppa or two will send them tossing and turning all night. Now, a new study in Scientific Reports suggests that this difference in tolerance could be associated with a single gene called PDSS2.
Researchers examined the genetic information and coffee drinking habits of 370 people in a small village in southern Italy and 843 people from six villages in northeast Italy, according to a press release. What they found was that coffee lovers with a certain variation of the gene PDSS2 drank one fewer cups of coffee per day.
A second survey conducted in the Netherlands on a group of 1,731 subjects also found that people with the gene variation drank a little less coffee than others. But the researchers point out that while the Italians tend to drink demitasse’s of espresso, the Dutch preferred larger cups of drip coffee with roughly three times the caffeine, meaning cutting out even a half cup is a significant reduction in intake.
Ian Sample at The Guardian reports that the researchers believe the tweaked gene reduces the rate at which caffeine is metabolized in the body, meaning it hangs around in the bloodstream longer. So people with the PDSS2 variation need less caffeine to get the same stimulation as other coffee drinkers—and the buzz lasts longer.
The study isn’t just limited to coffee. Lead researcher Nicola Piratsu, a geneticist at the University of Edinburgh says understanding the genetics of coffee could have wider implications for health. The body uses many of the metabolic pathways that break down the chemicals in coffee to process medications and well. Knowing how they work could help develop more personalized treatments.
“Coffee is protective against some types of cancers, cardiovascular diseases and Parkinson’s,” Pirastu tells Sample. “Understanding what is driving its consumption may help us understand what the effects on these diseases are, and so open new lines of research.”
This is not the first study on the genetics of coffee consumption; researchers have investigated the topic since the 1960s. In 2014, scientists examined coffee drinking habits of 120,000 people, finding six gene variations. Some of the variations associated with devout coffee consumers were also involved in glucose and lipid metabolism. This latest study suggests that PDSS2 may also get into the game, but more research is necessary to tease out the genetic intricacies of human devotion (or lack thereof) to coffee.