They were up to four times more likely to have a heart attack than slow-
metabolizers in their age group who drank little or no coffee.  The findings, though
preliminary, might explain why there have been such mixed results in previous
studies investigating caffeine's effects on the cardiovascular system, said
University of Toronto researcher Ahmed El-Sohemy, a study coauthor.
Caffeine is thought to block the effects of a certain chemical that is believed to
help protect against tissue damage, he said.  Some previous research has linked
coffee-drinking to a higher risk of heart disease, but other studies have suggested
the opposite. While there's evidence to suggest caffeine can cause short-term
blood pressure increases, a study last year said coffee-drinking didn't appear to
cause long-term high blood pressure, at least in women.  The new study ''clearly
illustrates that one size does not fit all," Sohemy said. ''Perhaps in the future we'll
be making different [dietary] recommendations based on people's genetic makeup."
For now, there's no easy way to know whether you metabolize caffeine slowly or
quickly.  Staying awake all night if you drink coffee in the afternoon doesn't mean
you're a slow metabolizer, and a genetic test that could answer the question is
used in research but is not commercially available, Sohemy said.  His study,
conducted with researchers from Harvard's School of Public Health and the
University of Costa Rica, appears in today's Journal of the American Medical
Association.  Participating were 2,014 men and women ages 58 on average who'd
had a nonfatal heart attack between 1994 and 2004, plus a control group of 2,014
healthy men and women.  Genetic tests of blood samples determined which ones
were slow caffeine metabolizers and which were fast metabolizers.  Sohemy
said the prevalence of both traits is similar in other population groups but worldwide
prevalence varies.  ''This data is very provocative and very interesting," said Dr. Roger
Blumenthal, a cardiologist at Johns Hopkins Medical School who was not involved in
the study.  Still, even if future research confirms the findings, it's likely that caffeine
plays a much smaller role in heart attacks than conventional risk factors like high
blood pressure, cholesterol, and smoking, Blumenthal said.Dr. Nieca Goldberg, an
American Heart Association spokeswoman, said that while the results aren't
conclusive, ''One good message that we can give people is that life is about
moderation."The study ''doesn't say you can't have caffeine," but drinking several
cups of coffee daily is probably excessive for some people, she said.  Coffee can
trigger heart palpitations in people who are sensitive to caffeine.  Those palpitations
may not be harmful, but they can be frightening, Goldberg said.

                                       By Lindsey Tanner, Associated Press | March 8, 2006