The difference between someone who sips a single cup of coffee in the morning and those who guzzle an entire pot before noon is genetic, according to a study published Tuesday in the journal "Molecular Psychiatry." Harvard researcher Marilyn Cornelis and her team found six genes that — along with two previously discovered genes — determine how humans react to caffeine. The study provides insight on why some people feel happy and energized after drinking a venti latte, while others feel nauseous after their first cup of joe. Cornelis hopes that the research could shed light on why coffee seems to have positive health effects for some people and not others. “We assume everybody reacts to one cup of coffee the same way," she told NBC News. "Our data says that is not true.” Overall, the new genes explain about 1.3 percent of coffee-drinking behavior, which is actually pretty significant, Cornelis said, meaning genes that influence coffee consumption are at least strong as those that influence how we react to alcohol and cigarettes. As for Cornelis, her interest in coffee is limited to research."I don’t consume coffee," she said. "I don’t like the taste of it."
— Keith Wagstaff