'Caffeine addiction linked to genes'
Sat, 09 Apr 2011 07:25:31 GMT
Scientists have found that two genes involved in the breakdown of caffeine in the liver are associated with the amount of caffeine people consume.
A team of the US researchers found that people who carry a particular version of two specific genes were much more likely to consume caffeine.
The two genes identified after analyzing genetic variation across the entire genome of more than 47,000 US individuals named CYP1A2 and AHR. The first one has been previously linked to the metabolism of caffeine, while AHR, involved in the regulation of CYP1A2, according to a report published in the journal PLoS Genetics.
Caffeine is the top psychoactive substance globally and more than 90 percent of people consume it mostly through different drinks such. Reportedly, at least eight out of 10 American adults who take in caffeine are coffee drinkers.
Two previous studies accounted genes for between 43 percent and 58 percent of the variability in coffee-drinking habits. However, the new research has linked the association to definite genes.
The people who carry the two identified genes tended to drink an average of 40 milligrams more caffeine a day, which equals a can of soda or a third of a cup of coffee, compared to those who did not have versions of those genes.
“People don't suspect, but genetics plays a big role in a lot of behaviors, such as smoking and alcohol consumption. And now it turns out that it has a big part in how much caffeine we drink,” said Dr. Neil Caporaso, the study's senior author of the National Cancer Institute.
"You might think, I drink caffeine to feel good, or not to feel bad, but that, in turn, is established by how fast your liver breaks down the caffeine," Caporaso added. "If your liver breaks it down very rapidly, then likely you drink more."