ATLANTA – The heart health consequences of coffee consumption have been hotly debated for years, but two recent studies suggest that the less a person drinks, the better.
The most recent study, which followed more than 3,000 coffee drinkers in Greece for two years, found troubling levels of inflammatory substances in their blood, compared with those who don’t drink coffee.
In other studies, those substances have been associated with higher rates of heart attacks and strokes, although the new study did assess whether the coffee drinkers were at more risk.
The study, which was presented here Sunday at the American College of Cardiology’s annual scientific sessions, comes on the heels of another study that found a troubling link between coffee consumption and non-fatal heart attacks in patients who had a specific genetic trait related to how quickly they metabolized caffeine. About 50 percent of the U.S. population has that trait.
That study, which was published last week in the Journal of the American Medical Association, involved 2,014 first heart attack patients in Costa Rica.
Those who slowly metabolized caffeine and who drank two to three cups of coffee a day had a 36 percent greater risk of having a non-fatal heart attack.
For those who drank four or more cups, the risk increased to 64 percent.
However, for those who were genetically predisposed to rapidly metabolize caffeine, there was as much as a 22 percent reduction in heart attack risk.
“It’s very muddy,” said James Stein, a cardiologist with the University of Wisconsin-Madison.
Stein noted that coffee also contains substances known as flavonoids that have been associated with improved heart health.
Yet, the Greek study found that men who consumed more than a cup of coffee a day had 30 percent higher levels of a particular inflammatory substance in their blood, compared with non-coffee drinkers. For women, it was 38 percent higher.
Various other inflammatory substances also were elevated in the coffee drinkers.
“Maybe it (coffee) is harmful when you consume high quantities,” said lead author Christina Chrysohoou, a cardiologist at the 1st Cardiology Clinic at the University of Athens. “Moderate consumption is the best.”
UW’s Stein said the study was well done, but it was not set up to completely rule out whether there was something else that was causing the increase inflammatory substances. For instance, coffee drinkers are more likely than non-drinkers to be smokers, less likely to exercise, and eat fewer fruits and vegetables, factors that tend to increase inflammation.
The study also did not address decaffeinated coffee, which may be more or less harmful to the heart, he said.
In the meantime, UW’s Stein said he advises his patients to limit the coffee consumption to one cup a day.
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AP-NY-03-12-06 2045EST
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