Have you ever noticed that a cup of coffee can affect people very differently? You might be able to drink a few cups of your favorite roast and take a nap an hour later without a second thought, while your close friend might get the jitters after just half a cup. You might have chalked this up to caffeine tolerance – after all, caffeine is a drug – but it might be deeper than that. A new study published in the journal Molecular Psychiatry found that genetic variants explain why same amount of coffee can have different effects in different people.
Researchers from the Harvard School of Public Health and Brigham and Women’s Hospital studied over 120,000 coffee drinkers and found six genetic variants linked to coffee. Two are thought to play a role in the positive effects of caffeine, the happy stimulant effect that you get from your first cup, while others had impacts on glucose and fat metabolism, blood pressure regulation and addiction (to caffeine, for the purposes of this study). For instance, regular coffee drinkers were less likely to have high blood pressure than those who did not drink coffee. The study is interesting in part because it focused specifically on coffee and the caffeine in coffee, not just caffeine from general sources, and the fact that they identified links to coffee specifically help to explain why so many other studies have found health benefits related directly to coffee consumption.