Regardless of where in the world you live, a daily cup of coffee is a pretty much universal indulgence. More than 50% of Americans drink coffee at an average of 3 cups per day, but everybody’s coffee consumption is different. Some guzzle coffee nonstop throughout the day, while others prefer to keep it light with just one cup. Previous research published in the journal Molecular Psychiatry suggests that certain gene variations determine how the body metabolizes coffee, which may impact how much coffee a person drinks.
A new study out of the Usher Institute at the University of Edinburgh and published in Scientific Reports suggests that a specific gene variation may also influence how many cups of coffee one typically consumes in a day.
How Many Cups of Coffee Do You Drink? 
Researchers examined the genetic composition of 1,213 Italian men and women from north-east Italy and southern Italy. Participants answered a questionnaire on how many cups of coffee they drank each day. Results showed that people with a DNA variation in the gene PDSS2 drank one less cup of coffee each day on average than did those without the gene variation.
Researchers tested their findings on 1,731 men and women living in the Netherlands. Results were similar; however, the reduction in coffee drinking among those with the PDSS2 variation weren’t as pronounced. Researchers attribute this to the cultural differences in coffee drinking in the Netherlands versus Italy. In Italy, cups of coffee are much smaller, such as espresso, while in the Netherlands, cups of coffee are much larger and the caffeine intake substantially higher.
How Does the Gene Variation Work?
Researchers do not yet know exactly how or why this gene variation exerts its influence, but they believe it may decrease the cells’ ability to metabolize caffeine. Therefore, those with the gene variation experience the stimulus of caffeine for longer than those without the variation, which may explain why they drink one less cup of coffee each day.
Study co-author Dr. Nicola Pirastu explains, “The results of our study add to existing research suggesting that our drive to drink coffee may be embedded in our genes. We need to do larger studies to confirm the discovery and also to clarify the biological link between PDSS2 and coffee consumption.”
