'Ask the Experts' - Questions and Answers
This facility is intended for use by healthcare
professionals only. However, if you are not a healthcare professional
but do have a question about coffee, please visit the British
Coffee Association websitefor
further information.
The Coffee
BREAK Campaign is advised by a multi-disciplinary Expert Panel including
GPs, Dietitians, Nutritionists and Nurses.
The Ask the Experts section
contains answers on a wide range of coffee and health related questions
put together by our Expert Panel. If you have a question, browse through
the answers we have already published to see if you can find what you're
looking for. Otherwise, you can email a question which will be answered
by one of our panel of experts.
We aim to reply to all emailed
questions within 72 hours
Q: Why do I need to know about coffee?
A: Most patients enjoy coffee,
and would be delighted to hear that it is safe for them to continue
drinking it in moderation. Healthcare professionals spend large proportions
of their time giving health promotion advice, much of which includes
advice about lifestyle and dietary modification. To maximise the
notice that patients take of such lifestyle advice, it is important
to limit the number of suggestions for alterations made. Moderate coffee
consumption of 4-5 cups per day* is perfectly safe for the general
population. As such, there is no reason to routinely advise patients
to reduce or eliminate coffee from their diet.
What are the 'headline' facts?
- Coffee consumption of up to 4-5 cups
of coffee* is perfectly safe for the general population
- In pregnancy, 200mg of caffeine a day (2-3
cups) is the recommended upper limit
- Coffee can contribute to the
daily fluid requirement
- Coffee can increase levels of alertness
- Moderate coffee consumption
is not associated with the development of heart conditions
- Moderate
coffee consumption is not associated with the development of
cancer
*this guidance can depend on the size and
strength of each serving as well as the intake of other foods containing
caffeine
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Q: What is the correct level of coffee consumption to recommend to
my patients?
A: Consumption of 4-5 cups of coffee per day* is perfectly
safe for the general population and can confer health benefits.
Pregnant
women should consider 200mg of caffeine a day (equivalent to 2-3
cups of coffee per day*) a safe upper limit.
*this guidance can depend on the size and strength
of each serving as well as the intake of other foods containing caffeine
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Q: Does coffee count towards the recommended daily fluid intake?
A: Yes.
Coffee can be an important source of fluid in the diet. Most healthy
adults need around two litres of fluid a day. Drinks (including
coffee) and food can both contribute to this. In fact advising people
to reduce their regular coffee intake could result in an overall reduction
of fluid intake.
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Q: Has research shown that coffee is bad for your health?
A: Coffee
is the one of the most heavily researched commodities in the world
today and thousands of research projects have been carried out over
many decades. There is no conclusive evidence to suggest that moderate
coffee consumption – of 4-5 cups per day* – is
bad for health. In fact moderate consumption is perfectly safe for
the general population and may confer health benefits. Pregnant women should
however moderate their intake following the guidelines issued by the Foods
Standards Agency, to 200mg caffeine per day from all sources.
*this guidance can depend on the size and strength
of each serving as well as the intake of other foods containing caffeine
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Q: How long does it generally
take from the time of caffeine ingestion for one to benefit from its
mental alertness side-effect and also for the caffeine's effect to
wear off in this respect?
A: Caffeine concentrations in the blood peak somewhere between 15
and 120 minutes and the half life (the time taken to halve the concentration)
of caffeine is between 2.5 and 4.5 hours.
Accordingly I suggest you advise
your correspondent that maximum effects on alertness will be achieved
within 90 minutes and that these will be lost after four hours. However,
there is clearly some individual variation which depends on genetics
and body mass index among other things.
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Q: I heard some time ago that something
in the decaffeinating process was unhealthy, particularly for the heart.
I've
read nothing since. Any ideas?
A: There are three different methods of decaffeination, water, carbon
dioxide or solvent, though the end result is more or less the same.
All methods safely and selectively remove the caffeine leaving a maximum
of 0.3%.
The concerns raised by your friends are due to the fact that one of
these methods uses solvents. It is a commonly held misconception
that this method is in some way dangerous but I am pleased to tell
you that this is simply not the case. Solvents, which can be
used to selectively remove caffeine from green beans, include methylene
chloride (dichloromethane), and ethyl acetate, which is a natural component
of fruits, vegetables and many other foodstuffs.
The process involves using a solvent to dissolve the caffeine out
of pre- wetted green beans. The solvent is removed, and the caffeine
distilled out of it, so that the used solvent can be re-utilised in
a further round of decaffeination. The decaffeinated green coffee beans
are then dried, and ready for roasting. The roasting and grinding process
further evaporates any minute residues of solvent, which might remain
in the coffee, and there are strict European limits governing the levels
of any solvent residues in the decaffeinated beans. In fact, manufacturers
operate well below these limits, ensuring the purity of the final product.
There is no health risk whatsoever associated with drinking moderate
amounts of either caffeinated or decaffeinated coffee and you can continue
to enjoy your favourite beverage with or without its stimulating properties.
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Q: Where does properly made espresso
stand in relation to diterpenes?
A: Espresso coffee, brewed in the Italian style, contains moderate
levels of diterpenes. The practical implications of this finding with
respect to cholesterol have been specifically studied, and the results
show no effect on total, LDL or HDL cholesterol levels. I am
therefore happy to reassure you that with moderate consumption (up
to 400mg caffeine a day, translating into 4-5 cups of espresso a day)
there are no significant risks to your heart from any effect on cholesterol.
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Q: Any thoughts on coffee and
mild depression? Some people report feeling detached and a bit woolly
headed if they have a bit too much caffeine over a period of time.
Any reason to cut down when on anti-depressants (citalopram)?
A: There is no evidence that moderate levels of caffeine consumption
affects depression. However, drinking very large quantities of caffeine
can cause a 'withdrawal effect' if caffeine is stopped
suddenly, and the symptoms have been reported to include mental depression.
People who suffer from depression can sometimes have a significant
level of anxiety as well – the condition of 'mixed anxiety
depression' is well
recognised. Caffeine, especially in large doses, can give rise to anxiety in
susceptible individuals (such as people who are already suffering from a degree
of anxiety). However, studies looking at moderate coffee intake (up to 400mg
caffeine a day, translating into 4-5 cups of coffee a day) have not found any
conclusive link with anxiety.Caffeine certainly increases levels of alertness
and vigilance – which for many people, of course, is a useful effect.
Overall,
then, there is no evidence to support cutting down on coffee intake if you are
suffering from depression and taking citalopram, as long as:
- You are not drinking more than moderate levels
- You do not have significant anxiety connected with your depression
There are three different methods of decaffeination; water, carbon
dioxide or solvent. The end result is more or less the same, with
all methods safely and selectively removing the caffeine. However,
the caffeine remaining is dependent on the type of coffee. After the
decaffeination process soluble coffee will have a maximum of 0.3%
caffeine remaining and 0.1% caffeine in roast and ground coffee.
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Q: Is coffee addictive? Do you experience side effects after reducing
your intake?
A: Coffee is not addictive as coffee drinkers do not require
increasing amounts of caffeine over prolonged periods of time (characteristics
of addictive substances), and they can moderate or change their consumption
with no difficulty. However, a very small percentage of the population
may experience minor symptoms such as headache if they suddenly stop
consuming caffeinated beverages, but these symptoms only last for
a couple of days with no long term adverse effects. These symptoms
are not experienced if a person gradually reduces intake or gradually
switches to decaffeinated coffee.
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Q: Do you become immune to the benefits of caffeine over time – and
should you therefore consume increasing amounts of coffee to obtain
the same satisfaction or stimulation?
A: People naturally find a level
of consumption with which they feel comfortable. This may or may
not change with time (either up or down), but there is no need for
continually increasing consumption to maintain satisfaction.
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Q: Is coffee bad for the heart and particularly bad for people who've
already been diagnosed with cardiovascular illness?
A: No, research
to date has shown that drinking coffee in moderation is not associated
with the development of cardiovascular problems, including atherosclerotic
disease, myocardial infarction, ventricular arrhythmias and hypertension.
Studies have also shown that moderate caffeine intake does not increase
the frequency or severity of cardiac arrhythmias in adult patients,
including those with ischaemic heart disease.
A few patients may be
particularly sensitive to caffeine, but this is not so for all cardiac
patients, as research has shown that caffeine does not make their
condition worse.
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Q: Does drinking coffee have an effect on blood pressure
A: Coffee
drinking may lead to a small, short-lived increase in blood pressure.
This increase is similar to the rise in blood pressure that would
be experienced when running up the stairs or during a heated conversation,
for example.
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Q: Does drinking coffee have an effect on palpitations?
A: Research
has shown that people who are susceptible to palpitations may experience
irregular heartbeats whether they consume coffee or not.
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Q: Is abstention from drinking coffee healthier for the heart? Will
it reduce blood pressure?
A: There is no conclusive evidence to suggest
that abstaining from drinking coffee has any direct benefits on either
general cardiac health or blood pressure.
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Q: Do people who drink coffee have higher cholesterol levels than
those who do not?
A: In general, people who drink coffee do not have
higher cholesterol levels than people who abstain from coffee drinking.
Only coffee that has been brewed by the boiled method, peculiar to
Scandinavia, has consistently been found to raise serum cholesterol
levels. This effect can be removed by simply filtering the boiled
coffee before drinking.
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Q: Does either coffee or caffeine cause cancer?
A: There is no conclusive
evidence which suggests that this is so. Indeed, in 1997, the World
Cancer Research Fund published a comprehensive review of diet and cancer.
In regards to coffee it stated: "Most
evidence suggests that regular consumption of coffee and/or tea has
no significant relationship with the risk of cancer at any site".
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Q: Why has some research suggested that coffee drinking is associated
with an increased risk for certain cancers?
A: Such studies, which
tend to be in the minority, are often inconclusive, or have arrived
at results which are statistically insignificant. A cause effect
relationship is not the only explanation for an association. Therefore
studies of associations between coffee drinking and cancer need to
be carried out very carefully. A prospective cohort study is much more
reliable than a retrospective case control study. The study results
always need to be corrected for other risk factors for cancer including
smoking, diet, exposure to environmental chemicals and infection. It
must also be shown that the association is statistically significant.
When these criteria are applied to studies of associations between
coffee drinking and cancer then there is no evidence for believing
that moderate consumption of coffee increases the risk of developing
cancer at any site.
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Q: Is it true that coffee can have a protective effect on the development
of certain cancers?
A: Some studies have suggested that coffee consumption
can have a protective effect against the development of cancer at
certain body sites, however, further research is needed before it can
be stated categorically that coffee protects against cancer. It is
certainly of note that coffee does not cause cancer, therefore patients
can continue to drink coffee without cause for concern.
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Q: Do women need to stop drinking coffee when they are pregnant, trying
to conceive or breastfeeding?
A: No. The Food Standards Agency advises
that pregnant women should consider 200mg of caffeine a day (equivalent
to 2-3 cups of coffee per day*) a safe upper limit. Some studies
have suggested that levels of caffeine intake over 200mg per day may
be associated with a low birth weight, and in some cases miscarriage.
Furthermore research has shown that drinking moderate amounts of coffee
does not have an adverse effect on fertility.
*this guidance can depend on the size and strength
of each serving as well as the intake of other foods containing caffeine
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Q: Is coffee a stimulant?
A: The caffeine in coffee is a mild central
nervous system stimulant, which can help increase alertness and
attentiveness.
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Q: Can you drink caffeinated coffee before going to bed?
A: There are
many external stimuli (including noise, temperature and discomfort)
which may affect how long it takes someone to get to sleep. Some
people, although not all, find that the mild stimulation of caffeine
consumed shortly before going to bed has this effect. Anyone who is
particularly sensitive can simply switch to decaffeinated coffee during
the evening. Evidence does not suggest that caffeine affects the quality
of sleep, or different phases of sleep during the night.
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Q: Should you avoid coffee it if you suffer from panic or anxiety
attacks?
A: Actually research has shown that caffeine does not cause
symptoms of anxiety in the general population. However some people
with diagnosed panic or anxiety disorders may find their symptoms exacerbated
by the stimulant effects of caffeine. It doesn't mean that these
people need to `avoid' coffee as research suggests that they
may naturally find a level of caffeine consumption with which they
feel happy.
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Q: Is coffee harmful to the stomach? Can it cause ulcers?
A: No, there
is no conclusive evidence to suggest that drinking coffee is bad
for the stomach and research has shown that coffee drinking does not
lead to the formation of either gastric, or duodenal ulcers.
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Q: Should people who have ulcers stop drinking coffee?
A: There is
no need for patients with ulcers to stop drinking coffee if they
suffer no symptoms from it. Coffee itself does not impact on the severity
of ulcers.
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Q: Does drinking either
regular of decaffeinated coffee cause heartburn?
A There are many possible causes
of heartburn, including stress, or very rich or spicy foods. Many
people find that eating certain foods leads to heartburn, whereas other
people do not suffer. Sometimes people experience heartburn after drinking
coffee, but they may have also eaten something which causes these
symptoms.
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Q: Can drinking coffee lead to increased bone loss in women?
A: No,
research has shown that average coffee drinkers are no more likely
to experience bone loss than those who do not drink coffee. Urinary
calcium excretion may increase for a few hours after drinking coffee,
but this drops later on in the day thereby compensating for the increase.
Research has shown that caffeine has no bearing on the development
of osteoporosis, or on bone mineral density. Furthermore, milk added
to coffee can be an important source of daily calcium.
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Q: What are the benefits of drinking coffee?
A: There is evidence to
demonstrate that moderate coffee consumption can confer health benefits.
Studies have shown that caffeine improves
- Concentration
- alertness, reasoning
- intellectual effort and vigilance
Caffeine increases flow of blood to the kidneys and may help protect
against stone formation. Caffeine has long been known to help
asthmatics and many have found regular consumption of coffee to assist
in moderating attacks.
Drinking coffee has been shown to add a `feel good' factor and
lift some of the sluggish symptoms that are the common after-effects
of a cold.
Several recent research papers have been published that suggest coffee
drinking may be protective against the development of Parkinson's
disease and Alzheimer's disease. Recent research has also shown
that coffee may be protective against developing Type 2 diabetes. More
research is needed and is ongoing in both these areas.
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Q: How long does it generally take from the time of caffeine ingestion
for one to benefit from its mental alertness side-effect and also for
the caffeine's effect to wear off in this respect?
A: Caffeine concentrations in the blood peak somewhere between 15
and 120 minutes and the half life (the time taken to halve the concentration)
of caffeine is between 2.5 and 4.5 hours.
Accordingly I suggest you advise your correspondent that maximum effects
on alertness will be achieved within 90 minutes and that these will
be lost after four hours. However, there is clearly some individual
variation which depends on genetics and body mass index among other
things.
Back to top
Q: I heard some time ago that
something in the decaffeinating process was unhealthy, particularly
for the heart. I've read nothing since. Any ideas?
A: There are three different methods of decaffeination, water, carbon
dioxide or solvent, though the end result is more or less the same.
All methods safely and selectively remove the caffeine leaving a maximum
of 0.3%.
The concerns raised by your friends are due to the fact that one of
these methods uses solvents. It is a commonly held misconception that
this method is in some way dangerous but I am pleased to tell you that
this is simply not the case. Solvents, which can be used to selectively
remove caffeine from green beans, include methylene chloride (dichloromethane),
and ethyl acetate, which is a natural component of fruits, vegetables
and many other foodstuffs.
The process involves using a solvent to dissolve the caffeine out
of pre- wetted green beans. The solvent is removed, and the caffeine
distilled out of it, so that the used solvent can be re-utilised in
a further round of decaffeination. The decaffeinated green coffee beans
are then dried, and ready for roasting. The roasting and grinding process
further evaporates any minute residues of solvent, which might remain
in the coffee, and there are strict European limits governing the levels
of any solvent residues in the decaffeinated beans. In fact, manufacturers
operate well below these limits, ensuring
the purity of the final product.
Back to top
Q: Where does properly made espresso stand in relation to diterpenes?
A: Espresso coffee, brewed in the Italian style, contains moderate
levels of diterpenes. The practical implications of this finding with
respect to cholesterol have been specifically studied, and the results
show no effect on total, LDL or HDL cholesterol levels. I am therefore
happy to reassure you that with moderate consumption (up to 400mg
caffeine a day, translating into 4-5 cups of espresso a day) there
are no significant risks to your heart from any effect on cholesterol.
Back to top
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