Study shows DNA may influence coffee preferences

How do you take your coffee? Your answer to that question might be dictated by your DNA.

That is the implication of a recent study in Scientific Reports that delves into the genetic markers of coffee drinkers.

It showed that people whose genes predispose them to metabolize caffeine quickly like to take their coffee black and prefer dark chocolate over milk chocolate.

The researchers looked at genetic information collected from people who had also completed extensive reports about their diets, including how much coffee or tea they consumed and how they sweetened it, if at all.

They also looked at self-reported preferences for bitter flavors such as those found in some beers and dark chocolate.

The analysis revealed that people whose genes pointed to quicker caffeine metabolism were more likely to prefer the taste and smell of black coffee and dark chocolate.

However, the caffeine metabolizers did not tend to have the genetic variations associated with a preference for bitter tastes.

So why do they like bitter black coffee anyway?

The study points to the hot beverage’s perceived caffeine content.

Since people who metabolize caffeine see coffee’s effects wear off swiftly, researchers say, they seek out coffee they perceive to be as strong as possible.

“Our interpretation is these people equate caffeine’s natural bitterness with a psycho-stimulation effect,” said Marilyn Cornelis, an associate professor of preventive medicine and nutrition and medicine at Northwestern University and the study’s lead author, in a news release.

“They learn to associate bitterness with caffeine and the boost they feel. We are seeing a learned effect. When they think of caffeine, they think of a bitter taste, so they enjoy dark coffee and, likewise, dark chocolate.”

People with a genetic marker associated with higher sensitivity to caffeine’s effects reported less liking for the flavor of both sweetened and unsweetened coffee.

Cornelis hopes to use the study’s insights into the genetic markers associated with coffee and dark chocolate consumption to inform future studies on the health benefits of both foods.