Are you one of those people who can't function without a cup of coffee in the morning? Or maybe three cups of coffee in the morning?
A new study by an international team of researchers shows that the amount of coffee you drink each day may be determined by your genes. The amount you need to feel that caffeine buzz — and potentially to enjoy it — can depend on your DNA.
How it works: Led by Harvard T.H. Chan School of Public Health researcher Marilyn Cornelis, the study, published in the journal Molecular Psychiatry, looked at the genetic makeup of more than 120,000 people. Researchers found six genes that were more frequently found in regular coffee drinkers. These come in addition to two genes found during a 2011 study on the subject.
As Vox explains, some of those genes affect how you process coffee, including how long caffeine stays in your bloodstream. If you metabolize it faster, you're going to need more coffee to feel that euphoric buzz. This may also affect how much it takes to get you feeling sick and jittery.
Other genes affect how your pleasure centers respond to the caffeine, though it's unclear whether they make you happier to drink coffee or require more coffee to make you happy. Researchers estimate that 7.1% of the variation in coffee consumption between people can be explained by these genetic differences.
Moving forward: Cornelius calls this discovery "an important step forward in coffee research," which is totally a thing, apparently. The next frontier, it seems, is looking at what benefits coffee might have outside of caffeine.
"If, for example, caffeine is protective, individuals might have very similar physiological exposure to caffeine, once you balance the metabolism," Cornelius told the Harvard Gazette. "But if coffee has other potentially protective constituents, those levels are going to be higher if you consume more cups, so they might actually be benefitting from non-caffeine components of coffee. So it's a little bit complex."
Right now, it looks like the genetic component of coffee drinking is relatively small — genes explain about 1.3% of coffee-drinking behavior — but far from insignificant. That's the same impact our DNA has on smoking and drinking alcohol.