Activity of a gene that lowers levels of caffeine-degrading enzymes in the liver is associated with how much coffee people drink, researchers say August 25 in Scientific Reports. The more active the gene, called PDSS2, the less coffee people drank.
Researchers tracked the coffee-drinking habits of 1,207 people in remote Italian villages and 1,731 people from the Netherlands. The researchers looked for an association between sipping java and people’s genetic makeup. The Dutch quaffed, on average, more than five cups of filtered coffee per day; the Italians sipped about two cups of espresso.
In the Italians, 21 genetic variants in DNA surrounding the PDSS2 gene were linked to coffee consumption, Nicola Pirastu, of the University of Edinburgh, and colleagues found. The strongest-acting variant changed espresso consumption by 1.09 cups per day. Only five of the variants found in the Italians seemed to alter coffee-drinking in Dutch people, and did so to a lesser extent.
Given the larger size of the cups, Dutch people consume about three times as much caffeine per cup as the Italians do. Other caffeine-processing genes, such as CYP1A2 (SN Online: 4/8/11), may control coffee consumption habits at higher caffeine doses, while PDSS2 limits low-level caffeine intake, the researchers speculate.