Posted on 03/09/2006 4:29:05 AM PST by S0122017
Genes decide if coffee hurts or helps your heart 21:00 07 March 2006 NewScientist.com news service Roxanne Khamsi
Related Articles Coffee: The demon drink? 24 September 2005 Genetic engineers decaffeinate coffee 18 June 2003 Coffee drinkers have lower diabetes risk 08 November 2002 Search New Scientist Contact us Web Links Caffeine content of common beverages, Mayo Clinic Caffeine, MedlinePlus University of Toronto Journal of the American Medical Association
Coffee can raise or reduce your chances of suffering a heart attack – it all depends on your genes, researchers suggest.
People with a genetic makeup that causes them to metabolise caffeine more slowly have a 36% greater risk of heart attack if they drink two to three cups of coffee a day than people with the same gene who drink one cup or less a day, according to a new study. And if they drink more than four cups, this risk rises to 64%.
“Our data suggest that the longer caffeine is lingering in the system, the more harm it can do,” says Ahmed El-Sohemy at the University of Toronto, Canada, who led the study.
If you knew you had 'bad genes' for coffee consumption, would you cut back? Discuss this story >> On the other hand, individuals who metabolised caffeine quickly and consumed two to three cups of coffee a day had a 22% reduction in the risk of heart attack compared with those with the same genetic makeup who consumed just one cup or less each day.
Natural stimulant Other recent studies have highlighted both positive and negative effects of caffeine consumption. A previous survey of Dutch men and women suggested that heavy coffee drinkers had a lowered risk of developing the cardiovascular disease, type 2 diabetes.
Another investigation published in 2005 found that people who consumed decaffeinated coffee had higher levels of certain cholesterols in their blood than those who consumed regular coffee.
But much of the concern surrounding coffee’s potentially negative health effects has centred on the caffeine it contains. Research has supported the idea that caffeine, a natural stimulant, narrows blood vessels by blocking the effects of a hormone called adenosine, which normally keeps them widened.
Variations on a gene In the late 1990s researchers discovered that humans carry variants of the gene for an enzyme that breaks down caffeine in the body. People who carry two copies of the CYP1A2*1A gene may break down caffeine up to four times faster than those carrying the CYP1A2*1F gene, according to El-Sohemy.
He and his colleagues analysed the DNA of more than 2000 patients along with an equal number of healthy people matched for age, sex and area of residence.
Their retrospective study showed that two to three cups of coffee per day caused a 36% rise in risk of heart attack among people who carried the CYP1A2*1F gene – and drinking four or more cups a day caused a 64% increase in the same group. Increased levels of circulating caffeine may block adenosine’s action, causing blood vessels to constrict, subsequently triggering a heart attack, says El-Sohemy.
About 55% of those involved in the study carried the gene for slow caffeine metabolism.
Cup half full People who were homozygous for CYP1A2*1A – meaning they carried two copies of gene for fast caffeine-metabolism – actually reduced their risk of heart attack by drinking coffee. Among these volunteers, two to three cups of coffee caused a 22% decrease in heart attack risk. Drinking more than four cups of coffee only nominally reduced their chances of a heart attack.
This is the first time that scientists have done a systematic analysis of how genes can influence the effect of coffee on heart attack risk. The study is part of a larger trend in which scientists have untangled how genes make some diets and habits more beneficial or addictive for some people than for others.
Few people know whether they carry the CYP1A2*1F gene or not. But El-Sohemy stresses that having just one cup a day does not appear to have any adverse health effects. “It’s too premature to change dietary requirements,” he says, adding that follow-up studies are necessary.
Journal reference: Journal of the American Medical Association (vol 295, p 1135)
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A great opportunity to impose SINtaxes in the future.
First rule of taxation: Don't tax you, don't tax me, tax the guy behind the tree.
(The problem, of course, is that everybody is behind a tree.)
I tried to improve on the info given by the title
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