Dracii din cafea - posedatilor !
- From: "Ronin" <Kotyto@xxxxxxxxx>
- Date: 23 Sep 2005 15:01:16 -0700
Coffee: The demon drink?
IN THE middle of Portland, Oregon, is Pioneer Courthouse Square, a
welcome oasis of open space among the city's bustling shops and
offices. Business people and spiky-haired teenagers mingle here to wait
for a train, eat lunch, or just watch the world go by. But above all
they come here to drink. Even by the standards of this coffee-crazy
city, the square is awash with caffeine. From 5 am until midnight, some
of the city's busiest baristas keep the espressos and lattes flowing.
Caffeine is the most widely consumed psychoactive substance on earth,
prized by almost every human culture for its ability to perk people up
and keep them awake. In North America, around 90 per cent of adults
report using caffeine every day.
And when it comes to caffeine delivery systems, our ingenuity knows no
bounds. Starbucks, the world's largest chain of coffee shops, sells
more than two dozen types of coffee and tea. Chocolate is full of the
stuff. And throughout the industrialised world, food processing firms
are turning some beverages "decaf", only to "caffeinate" soft drinks,
pick-me-up pills and cold remedies.
But despite its popularity - or maybe because of it - many people feel
vaguely uneasy about their caffeine intake. There's the fact that it's
addictive. And then there are all the health fears. Odds are that you
have heard the rumours. Don't drink caffeine, it'll give you a heart
attack. Or a stroke. Or it'll damage your chromosomes. Or make you fat.
Or, or, or.
How worried should we be? True, there are mountains of papers linking
caffeine to all manner of health problems. But once you start digging,
caffeine's critics don't have much going for them beyond an almost
religious zeal to demonise the stuff. In fact, recent evidence suggests
they are dead wrong. Caffeine, it turns out, has a multitude of health
benefits. So much so that if most of us weren't drinking it already you
could argue the case for adding it to the water supply.
Caffeine consumption goes back perhaps 8000 years, but the bad
publicity is a much more recent phenomenon. One of the earliest
documented health scares came in 1911 when the US government sued the
Coca-Cola Company, claiming the caffeine in its drink was "injurious to
health" (Coca-Cola won).
Caffeine bashing started in earnest in the mid-1970s when several major
studies linked it with heart disease and bladder cancer. And that was
just the start. "I've probably read 4000 or 5000 caffeine and coffee
papers," says James Coughlin, an independent toxicologist in southern
California who's been advising the coffee industry for nearly a quarter
of a century. "Somebody has published a paper linking coffee or
caffeine with just about every disease known to man."
Perhaps the most notorious study came in 1980 when Thomas Collins of
the US Food and Drug Administration linked caffeine to birth defects in
rats. The study sent shock waves through the drinks industry and led
the FDA to warn pregnant women to cut down on coffee and tea.
In the study, Collins gave pregnant rats enormous doses of caffeine,
equivalent to 200 cups of coffee or tea in one gulp, via tubes inserted
down their throats. That method of force-feeding, known as gavage, is a
standard laboratory technique for getting foul-tasting substances into
lab animals. But it wasn't necessary with caffeine, which can simply be
added to drinking water. Recognising this, Collins redid his study in
1983 with the caffeine in the rats' water, thereby spreading the dose
out across the day in a more realistic fashion. This time there was no
increase in birth defects.
Most of the human studies also turned out to have methodological
problems. Some indeed showed statistical correlations between caffeine
consumption and the risk of getting diseases such as cancer, but they
failed to account for smoking - in part because the link between
cigarettes and cancer wasn't well understood at the time.
"There were a lot of spurious results," Coughlin says, pointing out
that while most smokers drink coffee, few people who avoid caffeine
smoke. But now that a new generation of studies allows for the effect
of smoking and other factors known to be linked to cancer, he says,
"any relationship to coffee has fallen away". Likewise the much-touted
link between caffeine and high blood pressure and heart disease.
Caffeine does raise blood pressure, but only in people who are not
regular users. In 2003, the US National Heart, Lung, and Blood
Institute quietly dropped a recommendation that doctors should advise
patients with high blood pressure to cut back on caffeine.
Even so, the steady drip, drip, drip of adverse publicity has
continued. One recent obsession has been the interplay between caffeine
and low-carbohydrate diets, some of which prohibit caffeine on the
grounds that it raises insulin levels and thus promotes fat storage.
Nutritionists, though, dismiss such simplistic advice. "There are
numerous processes involved in fat storage," says Linda Bacon of the
University of California, Davis. "It may be that caffeine can
simultaneously trigger some that are going to encourage weight gain and
others that encourage loss." The literature does not support the
assertion that caffeine raises insulin levels. If anything it has the
effect of depressing them by decreasing insulin sensitivity.
Another recent flap has to do with caffeine's undeniable addictiveness.
As every java junkie knows, if you skip your morning brew you'll be
fuzzy-brained and irritable and may also get a headache. No big deal,
you might think, and easily remedied. But to some it's no laughing
matter.
In a study published last October (Psychopharmacology, vol 176, p 1),
neuroscientist Roland Griffiths of Johns Hopkins University in
Baltimore, Maryland, argued that caffeine withdrawal was serious enough
to be added to the next edition of the psychiatrist's bible, the
Diagnostic and Statistical Manual of Mental Disorders. He reviewed all
the literature on caffeine withdrawal and uncovered a dismal litany of
symptoms, from headaches, fatigue and depression to vomiting and muscle
pain. He also concluded that the benefits of caffeine are an illusion:
coffee merely reverses the withdrawal symptoms.
"The words 'drug' and 'addiction' are powerfully emotive. Nobody robs
banks or commits murder for caffeine"
Jack James, a psychologist at the National University of Ireland in
Galway and arguably caffeine's fiercest critic, would certainly agree.
James has long argued that studies showing caffeine's positive effects
on altertness and mental performance are flawed because the volunteers
are habitual caffeine users whose performance on caffeine is being
compared with their performance without it. Caffeine doesn't make
anyone perform better, he argues: it merely restores them to a normal
level.
Caffeine supporters, however, believe that this is all a storm in a
coffee cup. Just ask anyone who has wrestled with insomnia after an
evening brew whether caffeine's effect is real or illusory. And sure,
caffeine is a habit-forming stimulant, but nobody abuses it. Take too
much and you feel jittery and anxious rather than getting high. And
nobody ever got mugged by a caffeine junkie. "An addictive drug is
something you commit a crime for," says Manfred Kroger, a professor
emeritus at Pennsylvania State University and spokesman for the
Institute of Food Technologists.
Caffeine researcher Lawrence Armstrong, an exercise physiologist at the
University of Connecticut in Storrs, agrees. "Caffeine is a substance
of dependence, not a drug of addiction," he says. "The words 'drug' and
'addiction' are powerfully emotive. Nobody robs banks or commits murder
for caffeine."
That's not to say that caffeine gets a completely clean bill of health.
One real risk, according to Walter Willett, a professor of epidemiology
and nutrition at Harvard School of Public Health, is a small elevation
in bone fractures among people drinking four or more cups a day. That's
because caffeine causes some degree of calcium loss, with a possible
effect on bone density. But that's easily offset by getting enough
exercise, calcium and vitamin D, Willett says. In addition, unfiltered
coffees such as espresso do appear to have components that increase
blood cholesterol. Since filtered brews do not have the same effect,
the culprit has to be some as-yet-unidentified component that stays in
the filter.
There are also lingering concerns over caffeine in pregnancy. The New
York based Center for Science in the Public Interest, a powerful
consumer group that has spent years battling nutritionless "food porn",
is largely unconcerned about caffeine for most people. But it does
advise pregnant women to switch to decaf. According to Michael
Jacobson, the organisation's executive director, the literature is
unclear but raises some concerns about reduced fertility, underweight
babies and (possibly) birth defects. The coffee industry disputes these
studies, but Jacobson sees no reason to take a risk. "For women who are
pregnant, it's not a great sacrifice," he says. For the rest of us,
though, he agrees that a couple of cups of coffee is no big deal.
Caffeine supporters, however, aren't content with merely countering the
critics. Over the past few years they have quietly been building the
case that coffee, at least, is positively bursting with healthfulness.
Nearly two dozen studies, for example, now show that coffee drinkers
have a 25 per cent reduced risk of colorectal cancer, Coughlin says.
And the more coffee you drink, the lower the risk.
In addition, several studies have shown reduced risk of liver cancer
among coffee drinkers, as well as lower incidence of Parkinson's
disease and type 2 diabetes. There are even some tentative findings
that caffeine may help stave off Alzheimer's disease, as well as
alcohol-related liver damage. And lest you think the coffee industry or
other interested parties funded the studies, these results were
by-products of large, multi-purpose cohort studies such as the Nurses'
Health Study, administered by Willett under a grant from the US
National Institutes of Health.
Willett has also found that coffee reduces the risk of kidney stones.
Drinking a lot of any liquid has a similar effect, but coffee is
particularly beneficial, probably due to its diuretic effect. Also, he
says, coffee lowers the risk of gallstones and, intriguingly, suicide.
"Probably coffee is a mild antidepressant, and for some people it's
just enough to pull them back from the brink," says Willett.
Nobody's really sure why coffee has such diverse benefits. "It'll be 15
or 20 more years before we nail these things down," Coughlin says.
"Many people think of coffee as a caffeine delivery vehicle, but in
coffee there are probably 2000 other chemicals."
Coughlin suspects that the anti-cancer effects are due to polyphenols,
a class of antioxidants widely touted as the health "goodies" in red
wine, chocolate, tea, and many fruits and vegetables. In lab tests, he
says, coffee trumps these other foods in terms of polyphenol content.
And a recent study by researchers at the University of Scranton in
Pennsylvania found that coffee is the number one source of antioxidants
in the US diet.
With such favourable press for coffee, why does caffeine keep on
getting it in the neck? Kroger believes that, in part, the problem
stems from young researchers trying to make names for themselves. The
temptation is to feed massive amounts of a common substance such as
caffeine to rats and see what happens. If the rats get sick, it's news.
Kroger also believes that the anti-caffeine sentiment is down to
health-food advocates' bias against processed foods, a class that
includes most caffeinated soft drinks. But he argues that some zealots
simply seem to have a puritanical attitude. It's as though they believe
that if God wanted us to be perky in the morning, we'd be that way
naturally, he says.
When the dust settles, the debate about caffeine turns out mostly to be
simple common sense. Too much caffeine will give you the jitters and
keep you up at night. It might even give you disconcerting but largely
harmless heart palpitations, and you'll suffer mild withdrawal symptoms
if you stop. But all things considered, caffeine is your friend. Worry
about something else.
Richard Lovett is a writer based in Portland, Oregon
>>From issue 2518 of New Scientist magazine, 24 September 2005, page 38
Caffeine cheats?
CAFFEINE isn't just shedding its bad reputation among the general
public. It is also enjoying a renaissance in the world of international
athletics.
For years, "excess" caffeine was banned in many sports as an illegal
stimulant, though the definition of excess varied from sport to sport.
Competitors knew to go easy on the coffee, and there are no records of
any competitor being stripped of a prize due to caffeine.
When the World Anti-Doping Agency (WADA) was created in 1999 to
harmonise doping rules across Olympic sports, it set out a general rule
that athletes are banned from taking performance-enhancing substances
that are either a health risk or "against the spirit of sport". (You
can't just ban all performance-enhancing substances because that would
include sports drinks, food, and even water.)
So how does caffeine measure up? It certainly appears to be performance
enhancing, at least for endurance sports. And coaches tend to believe
that it is a health risk for athletes, mainly because it is a diuretic
and so causes dehydration.
But in a study published in June in the International Journal of Sports
Nutrition and Exercise Metabolism (vol 15, p 252), Lawrence Armstrong,
an exercise physiologist at the University of Connecticut in Storrs,
examined the effects of up to 500 mg of caffeine a day and found no
evidence of dehydration.
Nor is it easy to argue that caffeine, even in large quantities, is
contrary to the spirit of sport. That's partly due to the difficulty of
distinguishing performance-boosting doses from ordinary, innocent
consumption. Another factor is that Olympic villages lay on unlimited
supplies of coffee, tea, and chocolate for athletes. "How can we ban
something we provide?" Armstrong points out.
WADA agrees. Initially, it had put excess caffeine on its list of
banned stimulants, but a few months before the 2004 Olympics, it
changed its mind and dropped the restriction.
.
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