Coffee Addict? You Can Blame Your Genes

New research suggests the reason some people rely on caffeine more than others comes down to more than coincidence.

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If you’re basically a walking zombie until after that second cup, thank Mom and Dad. While 80 percent of Americans drink caffeine on a daily basis, there’s a difference between sipping on some java and brewing an entire personal pot. New research explores why, for many of us, one cup just isn’t enough. And the findings show that genes may be partially to blame for your coffee addiction.

Researchers at Harvard School of Public Health and Brigham and Women’s Hospital looked at the genes of more than 120,000 people who regularly consumed coffee and found an overarching trend. The coffee drinkers tended to share a variation in six newly discovered genes, making them more likely to gulp down caffeine.

Those gene variants explain a statistically significant 1.3 percent of your decision to opt for a triple shot latte instead of a regular cup of coffee. That’s at least as high as the gene-based part of decisions linked with alcohol and cigarette consumption, NBC News reports. Four of the six newly linked gene variations have also been previously connected to smoking habits, as well as obesity. Both of these habits are tied to addiction.

Scientists have known caffeine is addictive since 1994, when research sponsored by the National Institute on Drug Abuse appeared in The Journal of the American Medical Association. Today, caffeine withdrawal is even classified as a medical disorder. The caffeine molecule looks a lot like adenosine, the stuff our bodies naturally produce that makes us feel tired. When caffeine blocks them off, we suddenly feel a lot more alert for a few hours. Our bodies also produce more dopamine and adrenaline, making us feel livelier. Brain cells compensate by growing more adenosine receptors, building tolerance, which explains where the addiction part comes into play. When we stop consuming caffeine, our brains are left chemically unbalanced, resulting, for many, in a gigantic headache. (For more details on how caffeine addiction works, visit Smithsonian.com)

The affected genes in the new research are closely related to caffeine and how it metabolizes, not taste preference, the Boston Globe reports. The idea is that those who metabolize caffeine faster are more likely to drink more of it. Those with only a couple of the gene variations are less likely to be heavy coffee drinkers than those with all six. The speed at which our bodies metabolize caffeine may also explain why coffee gives some people sweaty palms and nausea and others that much sought-after burst of energy.

“Coffee and caffeine have been linked to beneficial and adverse health effects,” Marilyn Cornelis, research associate in the Department of Nutrition at Harvard School of Public Health and lead author of the study, said in a statement. “Our findings may allow us to identify subgroups of people most likely to benefit from increasing or decreasing coffee consumption for optimal health.”