Your coffee habit may be genetic

Posted at 7:20 PM, Aug 28, 2016

Whether a cup of java will leave you craving more could be chalked up to your genes.

People with a newly identified genetic variant in their DNA, called PDSS2, may be inclined to drink fewer cups of coffee than others, according to a small study published in the journal Scientific Reports on Thursday.

“I actually was very surprised to find a new gene for coffee consumption,” said Nicola Pirastu, a chancellor’s research fellow at the University of Edinburgh’s Usher Institute of Population Health Sciences and Informatics, and lead author of the study.

“We believe that this PDSS2 genetic variant is impacting coffee drinking through the regulation of the speed at which caffeine is metabolized,” he said. “It has been observed before that higher levels of PDSS2 inhibits the expression of the genes metabolizing caffeine and thus the speed at which caffeine is degraded.”

The findings add to existing research suggesting that our espresso habits may be embedded in our genes, Pirastu said.

About 64% of American adults drink at least one cup of coffee a day, according to a 2015 Gallup poll.

For the new study, researchers analyzed medical and genetic data on 370 people from a small village in southern Italy, and 843 people from six villages in northeast Italy. The study participants also self-reported their daily coffee-drinking habits.

The researchers discovered that people with the PDSS2 variant reported consuming fewer cups of coffee than people without the variant.

When the researchers replicated the study with a group of 1,731 study participants from the Netherlands, they noticed similar results.

This variant is very common, and around 50% of the European population has either one or two copies of it,” Pirastu said. More research is needed to determine the variant’s prevalence in other populations as well as to clarify its biological link with caffeine.

A separate study, published in 2014, linked about a half-dozen other genetic variants in human DNA to the volume and frequency of people’s coffee-drinking behavior.

Although different statistical models were used, the previous research tested a few of the same genetic variations included in the new study. However, an association with coffee consumption was not found, said Marilyn Cornelis, assistant professor of preventive medicine at Northwestern University who led the 2014 study.

Therefore, it seems that the newfound variant’s impact on coffee consumption may be minor compared with the previously identified genetic variants, said Cornelis, who was not involved in the new research.
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“The [new] study is small relative to the previous genome-wide association studies of coffee consumption,” Cornelis said.

“Genes can exist in different forms from one person to the next. We can have ‘fast’ and ‘slow’ acting forms, and depending on what we’ve inherited, it can impact how our body processes or metabolizes nutrients or food constituents like caffeine,” said Ahmed El-Sohemy, professor of nutritional sciences at the University of Toronto, who was not involved in the new research.

People generally tend to self-regulate how much coffee they consume based on a balance of how caffeine in the beverage has positive benefits, such as mood-enhancing effects, and negative outcomes, such as anxiety or “jitters,” he added.

“To date, most of the genes identified that impact coffee-drinking habits encode proteins involved in caffeine metabolism,” Cornelis said. “Individuals genetically predisposed to consuming greater amounts of coffee are likely metabolizing caffeine quickly, and so to achieve and maintain the ‘caffeine buzz,’ they need to consume more,” she said. “Individuals also respond differently to caffeine, and as you can imagine, this response is an important factor underlying our drinking habits, as well.”

Scientists have long explored genetic links to our food preferences, and such research can help reveal the biology behind our eating and drinking behaviors as well as our health, Pirastu said.

“I think that food preference genes will give us a very good insight on why people like or do not like certain foods by highlighting the biology behind it,” he said. “This will help us to better understand not only how people behave, but also why, allowing us to help them change their non-healthy behaviors.”