Coffee addiction may be grounded in genes

USA TODAY

New research suggests two genetic variations determine whether a person drinks more or less coffee.

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New research suggests two genetic variations determine whether a person drinks more or less coffee.

New research suggests that individuals who carry a so-called "high-consumption" variation of either gene appear to drink more coffee, relative to those who carry a "low-consumption" variant.

"It's really an incredible story," said study co-author Dr. Neil Caporaso, branch chief of genetic epidemiology at the National Cancer Institute. "People don't really suspect it, but genetics plays a big role in a lot of behaviors, such as smoking and alcohol consumption. And now it turns out that it has a part in how much caffeine we drink."

The two genes in question are labeled CYP1A2 and AHR. The former has previously been linked to the process by which caffeine is metabolized, while AHR regulates the activity of CYP1A2.

"Now, it's been known for a few decades that this particular CYP1A2 gene is what metabolized caffeine," Caporaso said. "But using new technology, what we now showed for the first time is that this gene appears to be responsible for the inherited differences in how people drink coffee."

Caporaso joins colleagues from the Harvard School of Public Health, Brigham and Women's Hospital, the University of North Carolina at Chapel Hill, and others to report these findings in the April issue of PLoS Genetics.

The study, funded by the National Heart, Lung, and Blood Institute, noted that more than eight in 10 American adults who consume caffeine are coffee drinkers. Globally, caffeine is the most popular psychoactive substance, with 90% of people in the world consuming some form of it.

The findings about the genetic underpinnings of java consumption stem from a highly complex mapping of specific inherited traits alongside caffeine intake patterns involving more than 47,000 Americans of European descent in five different studies.

The meta-analysis of the studies, which were conducted between 1984 and 2001, examined average caffeine consumption estimates

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