The chances are you consume caffeine, 90 per cent of the world’s population does, but what sets apart a coffee guzzler from their cup-a-day compatriots comes down to two genes, according to a new study.

 

Researchers at Harvard School of Public Health, Brigham and Women’s Hospital and the University of North Carolina at Chapel Hill looked at five population-based studies that tracked the caffeine consumption of 47,000 people, over 17 years, by charting their intake of coffee, tea, soda and chocolate.

 

Coffee is the caffeinated beverage of choice for people in North America, being favoured by 80 per cent of us. But the component that drove people to consume vast amounts of this bitter beverage was previously unknown to scientists. “Many factors are linked to caffeine intake: social, smoking, preference, taste,” said Dr. Marilyn Cornelis, the lead author of the study.

 

“From our study we are able to say that it is the caffeine component that is really driving our behavioural propencity towards this beverage, otherwise we would have seen genes associated with bitterness show up,” Cornelis told the Star. Cornelis and her team found that those who consumed the most caffeine in the five studies examined shared a genetic trait — the CYP1A2 and AHR genes. CYP1A2 has long been associated with the metabolism of caffeine and AHR acts as a catalyst speeding up the rate the caffeine is metabolized in the body.