Chocolate Said to Help Blood Vessels
There's more good news for chocolate
lovers. Scientists have found that eating dark chocolate appears
to improve the function of important cells lining the wall of
blood vessels for at least three hours.
The study, involving 17 healthy
young volunteers who agreed to eat a bar of dark chocolate and
then get an ultrasound, found that eating dark chocolate seemed
to make the blood vessels more flexible, which helps prevent the
hardening of the arteries that leads to heart attacks.
But experts cautioned that the
weight gain from eating a lot of chocolate probably would cancel
out the apparent benefit.
Dark chocolate is rich in flavonoids,
which act as natural antioxidants chemicals that combat
the damage oxygen does to the body. However, that does not mean
that chocolate binges will ward off a heart attack, experts warn.
Cacao, the plant that chocolate
comes from, has for centuries been used for everything from medicine
to currency. Although enjoyed worldwide, until recently it was
considered a treat that provided fat and calories but no substantial
nutritional value.
Studies recently have indicated
that it releases the happy chemical seratonin in the brain.
However, during the last few years,
studies have suggested much to the delight of chocoholics
that it is rich in flavonoids.
The latest study, conducted by
cardiologists at Athens Medical School in Greece, set out to test
whether chocolate affected the functioning of the so-called endothelial
cells in the walls of the blood vessels, which are believed to
be affected by oxygen damage and are considered a mirror of the
overall health of the cardiovascular system.
The scientists, who presented their
work Sunday at Europe's most important cardiology conference,
gave 3.5 ounces of either dark, bittersweet, chocolate or fake
chocolate to 17 healthy volunteers.
On another day, the volunteers
were switched. They had no chocolate outside of the study, and
investigators did not know what each volunteer ate during the
study.
An ultrasound was taken of each
volunteer's upper arm to see the functioning of the endothelial
cells in the main artery. The cells accomplish their goal of controlling
the stiffness of the blood vessel by secreting several active
substances that regulate the flexibility of the vessel and influence
clot formation.
"During the chocolate session,
endothelial function was improved, whereas during the placebo
day there were no such changes," the study concluded. "The favorable
effects of dark chocolate lasted for three hours at least."
By improving the blood vessel flexibility
in apparently healthy people, dark chocolate emerges as perhaps
a power food, the scientists said.
"At this time, we do not know whether
regular intake of dark chocolate or other cocoa beverages could
result in a reduction of total cardiovascular" problems or death,
the study said.
Experts warned against gorging
on chocolate as a way to ward off heart trouble, reminding that
excess calories lead to weight gain, which is a powerful trigger
of heart problems. Any benefit to blood vessel flexibility would
probably be wiped out by the danger of the weight gain, they advised.
Also, while antioxidants in theory
help keep the heart healthy and looked promising in early research,
recent rigorous studies investigating whether antioxidant pills
such as vitamins A, C and E ward off heart attacks have shown
them to be useless.
Dr. Michael Gibson, associate chief
of cardiology at Harvard University-linked Beth Israel Hospital
in Boston, said the chocolate study was "interesting."
"There are a few basic science
reasons why this might be good, but keep in mind that antioxidants
also improved forearm blood flow but that didn't necessarily pan
out as an effective treatment," said Gibson, who was not associated
with the study.
Reference
Source 102
August 30, 2004
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