Addicted to coffee? It may be genetic, researchers explain

Whether you need coffee in the morning or despise it, your parents may be at least partially to blame.

SAN DIEGO (KSWB/KUSI) — New research suggests that coffee habits, whether in excess or scarcity, could be partially linked to genetics.

Researchers at UC San Diego recently examined and compared data from U.S.-based 23andMe, the personal genomics and biotechnology company that provides genetic testing services to help people gain a better understanding of their ancestry and genetic predispositions.

The study's senior corresponding author, Dr. Sandra Sanchez-Roige, a professor in the UCSD School of Medicine Department of Psychiatry and Department of Medicine, Division of Genetic Medicine, told Nexstar's KSWB/KUSI the DNA of over 100,000 individuals were scanned during the study.

"We are interested in coffee consumption because drinking excessively can be problematic; by identifying genetic variants associated with excessive coffee consumption we hope to learn something fundamental about why people may overconsume other substances," said Dr. Sanchez-Roige.

Specifically, the researchers examined genetic correlations and performed a phenome-wide association study across hundreds of biomarkers, health and lifestyle traits. From there, they compared the results to the largest available data on coffee intake from the UK Biobank.

The findings

According to the researchers, how much coffee you drink is partially due to your unique genetic makeup.

"We found that different versions of genes that metabolize caffeine influence coffee consumption, we suspect other influence, whether or not people like the feeling caffeine gives them, but that’s still an active area of research," explained Dr. Abraham Palmer, a professor in the UCSD School of Medicine Department of Psychiatry.

It appears, however, that it's not all about genetics. Other environmental factors appeared to also be of influence.

"Indeed, we found that the influence of genes of coffee consumption isn’t the same in the U.S. and the U.K., which emphasizes that both genes and the environment are important and shows that changing the environment can change the influence of genes on behavior," Dr. Palmer continued.

While using what was described as "some clever statistical techniques," the researchers also found that people who are genetically likely to drink more coffee are also likely to use more alcohol, nicotine, and other drugs.

"Because of the way we did this analysis, our results don’t necessarily mean that drinking coffee causes people to use other drugs. Instead, our results show that the same genetic differences that make people more likely to choose to drink coffee also make them more likely to choose to use other drugs," explained Dr. Palmer.

The UC San Diego professor said further research could examine whether there is a cause-and-effect relationship between caffeine and other drugs. Nonetheless, he believes their results shouldn't cause people to avoid caffeine.

"We also found that genetic variants associated with coffee consumption are shared with anxiety, depression," Dr. Sanchez-Roige explained further. "We cannot extrapolate from our study that drinking coffee causes these conditions but it suggests that there is shared biology between drinking coffee and these conditions."

One cup, four cups, or no coffee at all — your choices when it comes to consumption may very well be linked to your genetic makeup.

Still, researchers note more investigation is needed to determine the relationship between genetics and environment on coffee intake, as well as other substance-use issues.