Addicted To Coffee? It Could Be Genetic, Says Harvard

Whether you gulp your way through multiple cups of coffee a day just to remain human, or you can barely finish a mug before you're vibrating off the walls, it turns out that there are six genetic variants responsible for your relationship with coffee.

In a genome-wide meta-analysis from the Harvard School of Public Health of a sample of more than 120,000 regular coffee drinkers (of European and African American descent), researchers identified two variants that were mapped to genes involved in metabolizing caffeine.

Another two gene variants are now thought to "potentially influence the rewarding effects of caffeine," according to a press release from Harvard, and the last two genes, involved in glucose and lipid metabolism, hadn't previously been linked to the metabolism or neurological effects of coffee.

What does this all mean? The research seems to suggest that people are able to "naturally modulate their coffee intake to experience the optimal effects exerted by caffeine, and that the strongest genetic factors linked to increased coffee intake likely work by directly increasing caffeine metabolism."

In other words, if you do possess these variants, your body reaps the caffeine rewards of coffee more quickly than others, which makes you more inclined to continue drinking it.

"This might explain why people vary in not only their coffee consumption behavior but also the stimulating or rewarding effect that coffee produces," Marilyn Cornelis, research associate in the Department of Nutrition at Harvard School of Public Health and the lead author of the study, told USA Today.

The study appears online October 7, 2014 in Molecular Psychiatry.

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Karen Lo is an associate editor at The Daily Meal. Follow her on Twitter @appleplexy.