“I’m addicted to coffee, but it’s not my fault. It’s in my genes.”
That may sound like a joke, but there actually seems to be a connection between our coffee-drinking habits and our genes. 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 — have been 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, giving them a total of more than 120,000 subjects.
The participants described their coffee drinking habits, offering such details as how much they consumed daily. Then they allowed the researchers to scan their DNA. The researchers, who are part of the Coffee and Caffeine Genetics Consortium, were looking for any minute differences in the participants’ DNA that could be associated with curbing their coffee consumption, which is to say 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 so caffeine can be processed either more or less efficiently. BDNF and SLC6A4 were also identified and are loci related to the reward and reinforcement properties of caffeine as well as being predictive of coffee consumption.
GCKR and MLXIPL, the last and, according to the study authors, most surprising loci identified, hadn’t been previously linked to studies of behavior and, in fact, are related to the metabolism of sugars, particularly glucose and lipids. (Two others, AHR and CYP1A2, had been identified previously, according to the press release.)
The variants identified in the study have some important implications. First, the genes of coffee drinkers vary and allow them to process the caffeine from coffee either more or less efficiently. In turn, this is why some coffee lovers only drink one or two cups in the morning while others drink coffee continuously throughout the day.
Secondly, there are 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
The popularity and ubiquity of coffee make such studies extremely relevant, not only for marketing purposes but for general health and wellness as well (see video below).
The adverse effects of coffee have been known for some time now, yet we’ve found some distinct benefits to drinking coffee regularly as well, to the point where some suggest it should be categorized as a ‘health food.’
“Coffee and caffeine have been linked to beneficial and adverse health effects,” said 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,” said 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 admit that she doesn’t personally drink coffee.
She can’t stand the stuff.
Also published on Medium.