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ON COFFEE
(collected by Reza Ganjavi : www.rezamusic.com )
Caffeine's blood pressure effect persists in some
By Amy Norton Wed
Jun 22, 2005
NEW YORK
(Reuters Health) - Though some coffee drinkers develop a tolerance for
caffeine, those who don't may be sending up their blood pressure with each cup,
new research suggests.
In a study of regular caffeine consumers, researchers found
that many persistently showed small blood pressure spikes shortly after a large
dose of caffeine -- even when that dose came after several days of high
caffeine intake.
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Too Much Caffeine? Go Figure
Tue Sep 3, 2002
(HealthScoutNews) -- Without realizing it, you could easily be consuming
enough caffeine to be affecting your sleep or other aspects of your health.
Why? Because consumption of a little of this, a little of that and a bit of
something else containing this stimulant will put far more in your system,
far faster, than you may realize.
In addition to coffee, tea and many soft drinks, caffeine also is contained
in chocolate and many prescription and non-prescription drugs. Scientists
say that a combined consumption of more than 250 mg of caffeine a day can
increase your metabolism, raise your blood pressure and heart rate, and accelerate
breathing. It also can offset the effects of sleep deprivation, according
to the National Sleep Foundation.
Because caffeine content levels vary greatly from one food or beverage to
another, you might do well to check out the NSF's Caffeine Calculator ( http://www.sleepfoundation.org/caffeine.htm),
which reflects differences based on such things as the type of coffee bean,
brands of coffee, the way coffee is brewed and the way caffeine is presented.
This can be a highly valuable tool for those who want to avoid caffeine for
health or dietary reasons.
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Caffeine, Even in Small Doses, May Hurt Arteries
Fri May 17, 2002
NEW YORK (Reuters Health) - Small doses of caffeine--even as little
as that in one cup of coffee--can cause temporary stiffening of the blood
vessel walls,
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Friday February 16, 2002 12:45 PM ET
CORRECTED: Researchers Say Coffee Can
Raise Cholesterol
(corrects typo in first paragraph; causal
instead of casual)
NEW YORK (Reuters Health) - There may indeed
be a causal relationship between drinking unfiltered coffee
and high cholesterol levels, according to
results of a new study.
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Scientists See Possible Cancer Risk in Coffee
Tue Aug 27, 5:53 PM ET
BERLIN (Reuters) - German researchers said on Tuesday they had found traces
in coffee of a substance that some experts fear could cause cancer.
Researchers for German ecology magazine Oeko-Test discovered acrylamide,
which can cause cancer in animals, in all 24 brands of ground coffee and
seven brands of espresso they tested.
"It was known that there is acrylamide in coffee beans," Oeko-Test editor
Hella Hansen told Reuters. "We wanted to know how much of it gets into a
cup of coffee."
The test found the substance was present in brewed coffee, although in much
lower quantities than in ground coffee beans.
Preliminary scientific studies have found that acrylamide--a substance found
in french fries, potato chips, water and carbohydrate-rich foods such as
bread that are fried or baked--can cause cancer in animals.
The World Health Organization ( news - web sites) (WHO) said in June that
acrylamide was a cause of concern but more research was needed about the
possible effect on humans.
It repeated its long-standing nutrition advice--eat a balanced and varied
diet and limit consumption of fried and fatty foods.
The US Food and Drug Administration ( news - web sites) has also said the
information currently available about acrylamide is not sufficient to assess
the substance's impact on public health.
Coffee has been the subject of a wide range of studies, looking at its link
to cancer, heart disease and infertility.
According to the American Cancer Society ( news - web sites), "the vast majority
of studies agree that coffee has not been shown conclusively to have a link
to bladder, breast, lung, pancreatic, prostate or any other cancers."
Earlier studies found that some compounds in coffee seemed to be anti-mutagenic,
meaning they prevent DNA damage. Experts point out coffee is a highly complex
food and no studies of a single compound are likely to show for certain what
its health effects might be.
The head of the German coffee federation, Winfried Tigges, said acrylamide
was not present in raw coffee beans, but was formed when they were roasted.
He said coffee producers were researching ways of producing coffee without
the substance building up.
"It is an issue for us. It is not clear at the moment whether acrylamide
is dangerous for people, but if it is we want to get it out of coffee," he
told Reuters.
"Thank goodness, it is found in very low quantities in coffee, but all coffee
producers are carrying out research into how acrylamide is formed," Tigges
said.
Swedish scientists earlier this year prompted a worldwide food scare when
they reported finding high levels of acrylamide when carbohydrate-rich foods
such as rice, potatoes and cereals were fried or baked.
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Tuesday September 4 11:14 AM ET
One Cup of Coffee May Temporarily
Harden Arteries
By Kristin Demos
STOCKHOLM (Reuters Health) - The amount of caffeine in just
one cup of coffee could be enough to harden a person's
arteries for several hours afterward, according to a study
presented at the European Society of Cardiology Congress
here.
Hardened arteries, or atherosclerosis, put extra pressure on
the heart and increase the risk of heart attack and stroke,
researchers said. They noted that their findings could have
implications for people already at risk of these conditions.
``People must be careful with caffeine, especially if they have
high blood pressure,'' said Dr. Charalambos Vlachopoulos
from the Cardiology Department of the Henry Dunant Hospital
in Athens, Greece. ``After drinking a cup of coffee, blood
pressure can rise up to 5 or even 10 millimeters of mercury.
The amount depends on the individual and dose.''
``Regular rises of this magnitude are important in a person's
long-term prognosis and could increase their risk of suffering
from a stroke or heart attack,'' Vlachopoulos said. ``I think that
people with high blood pressure...should consider reducing
their caffeine intake or having caffeine-free drinks.''
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Nov 18 2002
By Alison McCook
NEW YORK (Reuters Health) - The mysteries hidden inside a coffee cup may
be more multi-layered than many realized, results from a small study suggest.
Dr. Roberto Corti of the University Hospital in Zurich, Switzerland, and
his colleagues found that something other than caffeine may also affect
the cardiovascular systems of coffee drinkers. And for habitual drinkers,
another ingredient may eventually suppress some of caffeine's effects.
Corti explained to Reuters Health that coffee contains several hundreds
of ingredients, and the current findings demonstrate that "there is something
else that has some activity in our system."
Just what coffee does to the cardiovascular system remains unclear, Corti
and his team note in the rapid access issue of Circulation: Journal of the
American Heart Association (news - web sites) for December 3rd. Previous
research has found that drinking coffee can cause a slight increase in blood
pressure in some, while some studies have shown the beverage has no effect
on blood pressure or can actually reduce it.
In the current study, Corti and his team investigated the effects of regular
and decaffeinated coffee on six regular coffee drinkers and nine others
who said they opted for coffee only on occasion.
The investigators found that the blood pressures of occasional coffee drinkers
rose after they drank coffee, while regular consumers experienced no blood
pressure increase after drinking coffee. Both groups showed similar increases
in the levels of activity of their sympathetic nervous systems, a body component
that helps regulate blood pressure and heart rate.
Occasional drinkers also showed a blood pressure increase after drinking
decaffeinated coffee--a finding that suggests the beverage contains an ingredient
besides caffeine that could affect cardiovascular health, Corti told Reuters
Health.
But could the bodies of occasional coffee drinkers simply be reacting to
the taste of decaf coffee, associating it with caffeine and responding as
they would to regular coffee? Not likely, Corti said. Along with an increase
in blood pressure, these participants also experienced a jump in the activity
of their sympathetic nervous systems that lasted for 60 to 90 minutes, Corti
noted, and such an extended change is difficult to explain by the previous
phenomenon, known as the placebo effect.
To explain why the blood pressure of regular coffee drinkers didn't jump
after a cup of java, Corti suggested that something may suppress the effect
of caffeine on blood pressure--either an ingredient in the coffee or a change
that occurs in the bodies of regular drinkers.
Additional experiments revealed that while regular coffee drinkers may
develop some type of tolerance to the beverage, it is not to the caffeine,
Corti noted. When the researchers administered an IV that contained caffeine
or placebo and didn't tell participants what they received, both groups had
a similar increase in blood pressure and sympathetic nervous system activity
after an IV of caffeine. None responded to the placebo IV.
In an interview, Corti said the findings don't suggest people who drink
coffee should stop in order to protect their cardiovascular health, although
the study did not examine the effects of heavy coffee drinking on blood pressure
and nervous system activity. For those who drink one cup a day or so, the
beverage is reasonably safe, the researcher said.
SOURCE: Circulation 2002;106:2935-2940.
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Thursday October 25, 2001 2:12 PM ET
Caffeine, Genes Tied to Bone Loss in Older Women
NEW YORK (Reuters Health) - An appetite for coffee and chocolate
can take its toll on the bones
of elderly women, especially those with a particular genetic
mutation, researchers report.
The investigators found that in a group of women whose average
age was 71, those who consumed
the most caffeine had significantly lower bone mineral density
(BMD) after 3 years compared with
women who consumed the least. BMD is a marker of bone strength.
Women with two copies of a
gene with a mutation in the vitamin D receptor were even more
prone to bone loss, the report
indicates.
The findings add weight to research linking caffeine consumption
to the bone-thinning disease
osteoporosis, which can raise the risk of fractures in the
elderly. However, until doctors are able to
more easily determine which patients carry the genetic risk
noted in the study, it is too soon to advise
people to avoid caffeine, Linda K. Massey, from Washington
State University in Spokane, writes in
an accompanying editorial.
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Friday November 30, 2001 1:33 PM ET
Caffeine May Up Miscarriage Risk for Some Women
By Merritt McKinney
NEW YORK (Reuters Health) - Contrary to what researchers expected
to find, women who rapidly
metabolize caffeine may be at risk for having a miscarriage,
unlike women who take longer to clear
caffeine from their bodies.
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Claudia W: Coffee IS addictive. A friend of mine does anything to get
his coffee - he can stop a whole group from walking because he hasn't
got his coffee in the morning. He says if he doesn't get it he's angry
and you can't talk to him.
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Wednesday August 30, 2000 5:29 PM ET
Coffee drinking may damage blood vessels
AMSTERDAM (Reuters Health) - Drinking coffee, the world's most widely
consumed pharmacologically active substance, has potentially
harmful effects
on blood vessels, according to research presented here this week
at the 22nd
Congress of the European Society of Cardiology.
Dr M. O'Rourke and colleagues at St. Vincent's Hospital, Sydney, Australia,
presented data linking caffeine consumption with alterations
in the aorta, the
main artery supplying blood to the body.
In the study, 18 middle-aged healthy volunteers consumed 250 mg of
caffeine
(equivalent to 2 or 3 cups). The results showed that caffeine
led to a loss of
aortic elasticity, and raised blood pressure. The elasticity
of the aorta is linked
to heart function and coronary blood flow, the researchers say.
Monday November 13, 2000 5:33 PM ET
Drinking Filtered Coffee May Up Heart
Disease Risk
NEW YORK (Reuters Health) - People who enjoy several cups of
filtered
coffee each day may be putting themselves at increased risk
of heart disease,
preliminary study findings suggest.
Daily consumption of a liter of paper-filtered coffee was associated
with a
roughly 20% increase in homocysteine levels after 2 weeks,
according to the
report published in the November issue of the American Journal
of Clinical
Nutrition. Homocysteine, a compound that is produced when
the body
metabolizes protein, is a risk factor for heart disease.
Monday September 27 1:35 AM ET
BARCELONA (Reuters) - U.S. coffee consumption, already down 50 percent
per capita from 30
years ago, could fall to a ''critical low'' unless young people start drinking more, a leading industry
representative said Sunday. ``The population between 15 and 19 years
of age consumes 16 times less coffee today than the
previous generation did. It is dramatic,'' said Joaquim Leite, export director of Cooperativa
Guaxupe, Brazil's biggest coffee growers' cooperative.
European coffee representatives said marketing was key to stimulating demand.
``Coffee and tea will fit into a post-modern age. They are ideal for
post-modern advertising.''
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Caffeine causes changes in brain cells
NEW YORK, Oct 11,99 (Reuters Health) -- Caffeine may affect the process
of long-term
memory by changing the structure of dendritic spines, tiny ``branches'' found on nerve cells
in the central nervous system.
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DECAFFEINATING
COFFEE
by Saul N. Katz
CAFFEINE is a small, bitter-tasting
alkaloid. High-quality Arabica coffee
beans (the source of most specialty
coffees) are typically 1 percent caffeine by
weight, whereas cheaper and more bitter
Robusta beans have twice that amount.
Spurred by the belief that excessive
coffee drinking had poisoned his
father, the German chemist Ludwig
Roselius, in about 1900, found a
number of compounds that dissolved
the natural caffeine in coffee beans
without ruining the drink's taste.
Chloroform and benzene did the job
but were toxic, so for 70 years
methylene chloride became the
solvent of choice.
When it was discovered in the 1980s
to be a suspected carcinogen, the
chemical was abandoned by all the
big U.S. coffee labels. The Food and
Drug Administration continues to
permit the use of methylene chloride if
the residues in the coffee are below
10 parts per million. Processing for
specialty decafs still often uses it
because it perturbs other flavorings so
little.
Many other solvents can serve to
debuzz coffee. An "all-natural" label
may mean that ethyl acetate is the
solvent in use, because that chemical
occurs naturally in fruit. Water also
works as a means of decaffeination.
The so-called Swiss water process
soaks green coffee beans in a solution
that contains the chemical
components of beans dissolved from
a previous batch, except for the
caffeine. Because the water is already
saturated with sugars and peptides,
only the caffeine passes from the
beans into the water. [NOTE: in
mid-80's a study showed that
exposing coffee beans to high
temperature steam creates cancerous
chlosterols]
Another process, illustrated here, uses
supercritical carbon dioxide as a
solvent; in this state, the carbon
dioxide is intermediate between a gas
and a liquid. The variety of caffeine
extraction methods demonstrates that
a lot of sleepless nights have gone into
helping the world get a good night's
rest.
SAUL N. KATZ retired in 1989 as
a principal scientist at the Maxwell
House Division of General Foods.
He holds several patents on the
process for supercritical fluid
extraction of caffeine.