[Paleopsych] NS: Decaff coffee gives a buzz too
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Sat May 7 10:45:53 UTC 2005
Decaff coffee gives a buzz too
* 10:31 19 November 2002
* James Randerson
The buzz from your morning cup of coffee may not be caused by caffeine
after all. According to new research, decaffeinated coffee may be just
as good at raising the blood pressure, at least for drinkers not used
to the black stuff.
Numerous studies have shown that too much caffeine interferes with
sleep patterns, but the long term health effects of the drug are more
controversial. Some scientists claim that daily caffeine stimulation
increases our risk of high blood pressure and heart disease later in
But overall, the evidence is equivocal, says Alice Lichtenstein of the
American Heart Association's Nutrition Committee. Now, the small
Swiss-led study suggests that to focus on caffeine alone may be wrong.
The researchers gave triple espressos to six regular coffee drinkers
and nine volunteers who never consumed food or drinks containing
caffeine. On a separate occasion, the caffeine-abstainers also drank a
triple decaffeinated espresso, but they were not told which was which.
To the researchers surprise, both drinks had the same effect on the
non-coffee drinkers, stimulating the sympathetic nervous system and
raising blood pressure.
One interpretation of the result is that the subjects are reacting
like Pavlov's dog and receiving a "fake" caffeine hit in anticipation
of the real thing. But lead researcher Roberto Corti, a cardiologist
at University Hospital in Zurich, thinks this is unlikely because the
volunteers did not usually drink coffee.
"We also saw a linear trend in blood pressure. This is not typical of
a placebo effect," he adds. A more likely explanation, he thinks, is
that coffee components other than caffeine have a stimulating effect.
But the study threw up other puzzling findings. Regular coffee
drinkers did not experience higher blood pressure after normal coffee,
but their nervous system was stimulated.
Corti does not think this is due simply to their bodies having got
used to the effects of caffeine, because an intravenous caffeine
injection did raise their blood pressure. He believes that other
chemicals in coffee might block the caffeine stimulation.
But Lichtenstein says the result could be due to differences in the
method of delivery. Absorption via the gut can be slow and depends on
what the volunteer had in their last meal. "It's very different from
mainlining caffeine," she says.
"The study has raised questions," says Lichtenstein. But she thinks it
is too early to draw broad conclusions on the effects of caffeine and
Journal reference: Circulation (vol 106, p 2935)
* Coffee drinkers have lower diabetes risk
* 8 November 2002
* Caffeine 'lotion' protects against skin cancer
* 26 August 2002
* Caffeine key to curing a headache
* 29 October 2001
* University Hospital, Zurich
* American Heart Association
* Caffeine FAQ
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