Coffee may be linked to heart attack

Reported by Susan Aldridge, PhD, medical journalist

Certain gene variants are linked to an increased risk of a heart attack.
Previous work linking coffee and caffeine to health risks has been inconclusive. Now researchers at the University of Toronto reveal that coffee may indeed be a hazard for some. They were interested in how quickly the caffeine in coffee is broken down. This depends upon a gene called CYP1A2 which codes for a liver enzyme. There are different variants of this gene and, as this new study shows, this determines how fast caffeine is broken down and its effects on health.

A group of over 2,000 patients who had had a first, non-fatal, heart attack, and a similar group of controls were compared. DNA analysis showed which variant of CYP1A2 they carried and they were also asked about their coffee consumption. There are two variants of the gene - one linked to slow caffeine breakdown, one to rapid breakdown. In this study, about half in each group carried the slow variant. Analysis showed that having the slow variant increased heart attack risk by 36 per cent among those drinking two to three cups of coffee a day and by 64 per cent among those drinking four or more cups a day.

Those with the fast caffeine breakdown variant of the CYP1A2 gene had a reduced risk of heart attack - 22 per cent if they drank two to three cups, one per cent if they drank more. Therefore, it looks as if the caffeine in coffee does carry a risk of heart attack and that this is under genetic control.

Source
Journal of the American Medical Association 8th March 2006 Volume 295 pages 1135-1141