10 Oct 2014 Love or hate coffee? The reason may be genetic says new study
Scientists have long known that your DNA influences how much java you consume, but the new study has pinpointed six new genetic variants associated with habitual coffee drinking, and this is an important step forward in this research.
Four of the new variants implicate genes that are involved with caffeine, either in how the body breaks it down or in its stimulating effects, the researchers said in the paper, published in the journal ‘Molecular Psychiatry’.
The two other newly implicated genes were the most surprising, as they are not clearly linked to coffee of caffeine, but rather involved with cholesterol levels and blood sugar.
Marilyn Cornelis, research associate in nutrition at the Harvard School of Public Health and study lead author, attests “These are genes that we previously would not have implicated with coffee, and they show that there is some genetic basis for our coffee consumption behaviour. Out of 2.5 million variants in the genome, we found a handful that were strongly linked to coffee consumption.”
She goes on say that these genes could serve to explain why some people seem to enjoy coffee so much more than others, and explain why a given amount of coffee or caffeine has different effects on different people: “My response to a cup of coffee might be very different to someone else’s response to the same cup.”
The researchers from Harvard School of Public Health and Brigham and Women’s Hospital analysed 20,000 regular coffee drinks of European and African American ancestry.
They also analysed the results of around two dozen previous studies with a combined total of more than 120,000 people. Each participant described how much coffee they consumed a day and also allowed scientists to scan their DNA.
The new work looked for minute differences in the DNA of participants that were associated with drinking more or less coffee.
The resultant study suggests that people naturally curb their coffee intake to achieve the best effect caffeine can give them, and that the strongest genetic factors linked to increased coffee intake likely work by directly increasing caffeine metabolism.
Caffeine is a drug—a fact many of us forget until we madly crave a double shot. “There is controversy as to whether it can be addictive, and some of the genes that come up in the study suggest that’s quite possible,” Cornelis says. “The stimulating effects caffeine has would suggest that caffeine is a major driving in habitual coffee consumption at the genetic level.”
She adds: “Coffee and caffeine have been linked to beneficial and adverse health effects. Our findings may allow us to identify subgroups of people most likely to benefit from increasing or decreasing coffee consumption for optimal health.”
Daniel Chasman, associate professor at Brigham and Women’s Hospital and the study’s senior author, says: “Like previous genetic analyses of smoking and alcohol consumption, this research serves as an example of how genetics can influence some types of habitual behaviour.”
Cornelis notes that none of the identified genetic variants was related to how intensely a person tastes coffee, and Cornelis that this surprised her.
Study Reference:
http://www.nature.com/mp/journal/vaop/ncurrent/full/mp2014107a.html