Can you function without coffee? If you’re like a majority of Americans, your answer is probably no. More than 90 percent of adults regularly consume caffeine on a regular basis, with coffee being the main source. Not all adults drink coffee, however. Research suggests that genetics may explain why many adults habitually drink caffeine while others can’t tolerate it.
A study by Brigham and Women’s Hospital (BWH) and the Harvard School of Public Health discovered that coffee consumption habits can be partially attributed to our DNA. These findings come from a study observing DNA differences among 20,000 regular coffee drinkers of European and African American ancestry. Subjects self-reported how much coffee they drank on a regular basis. Results were compared to their DNA scans to test for any associations. The study discovered six new genetic variations that play a role in consumption behavior and metabolism of caffeine. Subjects in the study that had most of these genes present were found to consume more coffee as compared to those with fewer of these genes.
Of the six genes discovered, four of these regulate caffeine metabolism and response, while the other two genes are involved in glucose and lipid metabolism. The presence, absence, and any combination of these genes can influence how much coffee an individual needs to drink to achieve their desired caffeine effect.
These genetic variations can help explain why caffeine has different effects on different people. Those that possess more of these genes have better caffeine tolerance and are more likely to consume it – and more of it – compared to those who have fewer genes. People without the genes are more sensitive to caffeine and are likely to get jittery and anxious when they drink it. This is why some people need one cup a day, some need five, and others avoid caffeine altogether.
“Like previous genetic analyses of smoking and alcohol consumption, this research serves as an example of how genetics can influence some type of habitual behavior,” says BWH researcher Daniel Chasman, PhD, Associate Professor of Medicine at Harvard Medical School and the study’s senior author.
These findings can lead to new public health discoveries concerning the relationship between coffee and health. The health benefits and risks of caffeine have stirred up much contention in healthcare. Some of the potential benefits include reduced risk of Alzheimer’s disease and Parkinson’s disease. Other studies suggest coffee may increase risk of some forms of cancer. There is no conclusive evidence of any of these findings, though risks and benefits are likely to differ from person to person.
The study was published on October 7, 2014, in the journal of Molecular Psychiatry.