'Bean' drinking too much coffee? Your DNA can explain why

The term “all-nighter” is likely part of the vocabulary of many a student, office worker, or freelancer. Whether it’s a deadline that needs to be met, documents that need to be accomplished, or exams that need to be studied (or crammed) for, nearly everyone has been placed in a situation where they either had to tape their eyes open or down copious amounts of coffee just to stay up and get things done.

 

However, the capacity to drink coffee varies from person to person; some folks can manage to stay awake even without sipping a single drop of coffee, while others need a full pot just to keep themselves out of the Sandman’s realm.

 

If you’ve ever wondered why that’s the case, a recently-published study in Molecular Psychiatry presents an answer: our own DNA.

 

A latte new gene variants

 

The study, conducted by researchers from the Harvard School of Public Health and Brigham and Women’s Hospital, involved an extensive analysis of 120,000 regular coffee drinkers. 20,000 of the sample population were coffee drinkers of European and African American descent, while the rest of the respondents were derived from about two dozen previous studies.

 

By combining their findings (including data on the number of cups each person consumed per day) with the results from the earlier studies, the researchers were able to identify six new gene variants linked to caffeine consumption and attest to the presence of two previously discovered genes from a 2011 study by the same team.

 

Of the six newly identified gene variants, two (which mapped to GCKR and MLXIPL genes) were linked to cholesterol levels and blood sugar – “metabolic traits,” as the researchers wrote in their paper - but were not directly connected to coffee consumption. The remaining four (two of which were mapped to BDNF and SLC6A4 genes) were connected to caffeine, particularly in the way it is metabolized by the body.

 

The study’s findings revealed that participants who had inherited more or all of the newly identified gene variations had a greater tendency for increased coffee consumption - at least four cups of coffee a day - than those who had only one or two of the genes. The researchers explained that the presence of these genes increases the rate at which the body breaks down caffeine, thus resulting in a shorter period of caffeine stimulation (and a greater need for coffee) for participants who possessed more of the genes.

 

The good, the bad, and the coffee

 

An interesting takeaway from the study: While avid coffee consumers were less likely to suffer from high blood pressure than non-coffee drinkers, they were more likely to have increased cholesterol and blood sugar levels.

 

Additionally, one of the caffeine-linked genes was also connected to two health issues brought about by addiction: smoking and obesity.

“Coffee and caffeine have been linked to beneficial and adverse health effects,” explained Marilyn Cornelis, lead author of the study and a research associate from Harvard School of Public Health’s Department of Nutrition.

 

Cornelis also clarified that the genes identified in the study were “predominantly related to caffeine and its metabolism or effects elicited” and not drinkers’ taste preferences.

 

“Our findings may allow us to identify subgroups of people most likely to benefit from increasing or decreasing coffee consumption for optimal health.” — TJD, GMA News