Caffeine Craving Linked to Genetics

http://news.yahoo.com/s/livescience/20110407/sc_livescience/caffeinecravinglinkedtogenetics

Rachael Rettner, MyHealthNewsDaily Staff Writer,
LiveScience.com Rachael Rettner, Myhealthnewsdaily Staff Writer,
livescience.com – Thu Apr 7, 7:10 am ET

Whether or not you're a caffeine junkie is in part determined by your genes, a new study says.

The study identified two genes associated with the amount of caffeine people consume. Both of the genes are known to be involved in the breakdown of caffeine in the liver.

The findings suggest one of the main reasons why some people drink more caffeine than others is that the heavy drinkers are better able to tolerate it, the researchers say. The study did not find a strong link between caffeine consumption and genes involved in the brain's response to caffeine.

While both the liver and the brain influence caffeine consumption, "It turns out that your liver, more than your brain, determines daily caffeine intake," said study researcher Neil Caporaso, 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 said. "If your liver breaks it down very rapidly, then likely you drink more."

More than 90 percent of U.S. adults consume caffeine, and the findings provide insight into what influences this habit, which can be good or bad. In moderation, caffeine might counter cognitive decline, but too much can impair cognition, cut into sleep and even cause hallucinations.

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