“I’m a coffee addict, but it’s not my fault. It’s in my genes.”
That may sound like a joke, but actually it’s long been accepted that there are genetic links to our coffee-drinking habits. And according to a recent genome-wide meta analysis, eight genetic variants–two of which were already known and six of which were identified in this study–in particular have been identified as being correlated with habitual coffee drinking.
Genetic Link to Coffee Addiction
Researchers from Harvard School of Public Health and Brigham and Women’s Hospital looked at the genetics of 20,000 European and African American coffee drinkers in combination with the results of two dozen other studies for a total of more than 120,000 subjects.
The participants described their coffee drinking habits, such as how much they consumed daily, and allowed the researchers to scan their DNA. Specifically, the researchers, who are also part of the Coffee and Caffeine Genetics Consortium, were looking for minute differences in the DNA of individuals that would be associated with curbing their coffee consumption, drinking more or less coffee.
Their findings were quite interesting. For starters, they found that people naturally consume the “magical amount” to achieve the best effect that caffeine can give them, which will vary from person to person as each person has varying levels of tolerance to caffeine and each body processes caffeine differently. It was also found that the strongest genetic factors linked to increased coffee consumption are likely attributed to fluctuations in caffeine metabolism.
The Six Variants
According to the paper published in Molecular Psychiatry, four of the six genes can be attributed to caffeine and how it’s metabolized. Loci POR and ABCG2 act indirectly by altering the body’s metabolism of caffeine and allowing it to be process either more or less efficiently. BDNF and SLC6A4 were also identified and are loci perceptive to the reward and reinforcement properties of caffeine, also predictive of coffee consumption. GCKR and MLXIPL, the last loci identified and the most surprising to the study authors, had not previously been linked to any studies on behavior and in fact pertain to the metabolism of sugars such as glucose and lipids. (Two others, AHR and CYP1A2, had been identified previously according to the press release.)
These identified variants have told the researchers some very important things: Firstly, the genes of coffee drinkers vary and allow them to process the caffeine they get from coffee either more or less efficiently, which is why some coffee lovers will only drink one or two cups in the morning while others drink coffee continuously throughout the day. Secondly, there’s differences in how the brain perceives the drinking of coffee with some experiencing it as very rewarding, which could account for so many avid coffee enthusiasts. And finally, there are differences in how other components of coffee are metabolized by the body that will affect the optimal amount of coffee for each person.
Coffee and Health
These days, the popularity and availability of coffee has made studies on genetic links to its consumption relevant for many reasons, not only for marketing purposes but for general health and wellness as well (see video below). The adverse effects of coffee have been made public for some time now, yet we’ve also found there to be some distinct benefits to drinking coffee regularly as well, to that point that some suggest it should be categorized as a ‘health food.’
“Coffee and caffeine have been linked to beneficial and adverse health effects,” says Marilyn Cornelis, research associate in the Department of Nutrition at Harvard School of Public Health and lead author of the study. “Our findings may allow us to identify subgroups of people most likely to benefit from increasing or decreasing coffee consumption for optimal health.”
“I think it’s actually more healthful than tea,” says Dr. Frank Hu, professor of nutrition and epidemiology at the Harvard School of Public Health who has identified a connection between coffee consumption and lower risk for diabetes. Other studies have found coffee drinkers to be at decreased risk of gallstones, colon cancer, liver disease, and Parkinson’s.
According to the Cornelis, no gene variants were found to be related to taste, which was surprising to her. Cornelis went on to say she doesn’t personally drink coffee. She can’t stand the stuff.