Frequently Asked Questions
Coffee/Caffeine and Sleep
Habituation / Addiction / Withdrawl
Coffee Drinking and Fluid Balance
Coffee and Degenerative Brain Disease
Coffee / Caffeine and Anxiety
Coffee and Digestive Problems
Is coffee bad for the heart?
No, research shows that drinking coffee as part of a healthy balanced diet is not associated with the development of cardiovascular problems, including atherosclerotic disease, myocardial infarction, ventricular arrhythmias and hypertension.
Can coffee lead to any deterioration in those patients with already diagnosed cardiovascular illness?
Moderate coffee consumption is safe for many patients with heart disease. Anybody with concerns about their heart health should seek advice fro their doctor.
I have read somewhere that coffee drinking raises blood pressure, is this true?
Research has shown that caffeine consumption may have a small effect on blood pressure, however scientists do not consider coffee drinking to be an important risk factor for hypertension. The key risk factors are known to be a low potassium intake, high sodium intake, sedentary lifestyle and obesity.
Is stopping drinking coffee, and other caffeinated drinks, healthier for the heart and likely to lower blood pressure?
No. There is no conclusive evidence to suggest that stopping drinking coffee, or any other caffeinated drinks, has any direct benefits on general cardiac health. People who have concerns about their blood pressure should consult their doctor.
I have heard that coffee causes palpitations, is this true?
Research has shown that many individuals susceptible to irregular heartbeats (palpitations) will experience them irrespective of whether they drink coffee or not. If an individual is concerned about palpitations they should seek advice from their doctor.
I have heard that people who drink coffee have higher cholesterol levels than those who do not, is this true?
This commonly held misconception refers mainly to "Scandinavian Boiled Coffee" that has been shown to raise an individuals cholesterol levels by releasing high levels of the diterpenes, cafestol and kahweol, that have been identified as being responsible for the cholesterol raising effect observed with this brewing method where the coffee grounds are boiled in water and served without filtering. These diterpenes are sometimes referred to as "oils".
Are there any other brewing methods that have the same effect?
Some studies have suggested that coffee brewed by the ‘plunger pot’ (Cafetiere) method contains high levels of the diterpenes that have been shown to raise cholesterol, however it is of note that these studies tended to prepare the brew using high levels of ground coffee and therefore the results could be of no relevance to normal coffee consumption.
Are these "oils" found in all coffees?
No, Soluble, drip filter and espresso contain virtually none.
Is coffee drinking considered to be an important risk factor for hypertension / raised blood pressure?
No. Coffee drinking is generally not considered to be an important/significant risk factor for hypertension.
Does coffee drinking raise blood pressure?
Yes, though at levels that are no greater than would be experienced during everyday activities - such as taking part in a conversation.
What does cause raised blood pressure?
The prevalence of hypertension / raised blood pressure is increasing in Western societies at the known risk factors included being overweight, physical inactivity, having a diet high in sodium and low in potassium.
I have heard that homocysteine is a risk factor for heart disease and that drinking coffee will raise my levels of homocysteine, is this correct?
Homocysteine is a naturally occurring amino acid produced in our bodies to build proteins. In some people it may build up to a high level because of a deficiency in the body’s ability to break it down (or metabolise it). The scientific debate is not conclusive with two schools of thought, one being that raised homocysteine is a risk factor for cardiovascular disease, and the other being that it is simply a marker for cardiovascular disease. A small number of studies have been published suggesting that coffee drinking raised levels of homocysteine, however, whilst these studies showed a statistical association they were unable to suggest any plausible mechanism of action, or reason for this increase.
Should I stop drinking coffee if I am worried about my homocysteine levels?
No, there is no need to stop drinking coffee. If you consume a well balanced diet you should have no concerns about your coffee intake in relation to homocysteine levels.
Recently some researchers have been looking at the impact of caffeine on aortic stiffness. The research into this area of cardiovascular health is relatively new and extremely complex. Initial reviews of the literature raise several concerns as to the significance of the results, mainly because of the participants being given large amounts of caffeine that would not normally be found in a single cup of coffee. It is also of note that whilst aortic stiffness may be marker or indicator of possible cardiovascular risk, it has not yet been shown to be a significant causal factor in the development of these conditions.
Do either coffee or caffeine cause cancer?
There is no conclusive evidence to suggest that this is the case. In 1997 the World Cancer Research Fund published a comprehensive review of diet and cancer and in regard 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”.
Is drinking coffee associated with the development of bladder cancer?
In 1990, The International Agency for Research on Cancer (IARC) evaluated coffee, caffeine, tea and maté and, after assessing the available research, gave coffee the classification 2B which is ‘possibly carcinogenic to the human urinary bladder’. Since that time several well-conducted studies have been conducted and published which have demonstrated that coffee is not a causal factor in the development of bladder cancer.
Why has some research suggested that coffee drinking is associated with an increased risk for certain cancers?
Such studies, which tend to be in the minority, are often inconclusive, or have arrived at results that are statistically insignificant. It is highly unlikely that any single dietary factor consumed in moderation would be causal in the development of cancer.
Will coffee or caffeine consumption lead to an increased risk for breast cancer?
No. Research has found that drinking coffee is in no way associated with increasing a woman’s risk of developing breast cancer.
Does coffee or caffeine cause ovarian cancer?
No. There is no conclusive evidence that coffee/caffeine consumption increases the risk of ovarian cancer.
Is caffeine/coffee associated with an increased risk of pancreatic cancer?
No. People who drink coffee do not increase the risk of developing this disease.
Are factors other than coffee significant in the possible development of cancer?
Yes. Cigarette smoking has been proven as a major factor in the development of cancer at several sites in the body.
Is it true that coffee can have a protective effect on the development of certain cancers?
Some studies have suggested that coffee consumption may 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.
Is it safe for a woman who is pregnant, or contemplating pregnancy, to drink coffee and/or other caffeine containing drinks/foods?
Yes, in 1999 the EU Scientific Committee on Foodstuffs stated that ‘While intakes (of caffeine) up to 300mg/day appear to be safe, the possible question of effects on pregnancy and the offspring at regular intakes above 300mg/day remains open. This suggests that moderation of caffeine intake, from whatever source, is advisable during pregnancy’.
If coffee/caffeine is safe why do some research papers suggest the opposite?
A lot of these studies on reproduction are actually conducted on laboratory animals and it is not always possible to extrapolate these results to the human. Many human studies have shown no adverse effects on the foetus if a pregnant woman consumes a moderate amount of caffeine.
No. Reliable studies have shown that women who drink coffee are neither less likely to conceive nor less fertile than those who do not drink coffee.
What about men drinking coffee, will it affect their fertility?
No. Drinking coffee has not been shown to have an adverse effect on a man’s fertility, in fact some research has suggested that caffeine may increase sperm motility and thus improve male fertility!
Does drinking a moderate amount of coffee during pregnancy lead to abnormalities such as foetal or congenital birth defects in humans?
No. Moderate coffee drinking has not been shown to result in birth defects.
Can breast - feeding mothers who drink coffee harm their babies by passing on caffeine through breast milk?
No. Although caffeine can be found in breast milk, it is present in very small quantities, and normal coffee drinking women do not put their infants at risk.
Can pregnant women drink the same amount of coffee when they are pregnant as before?
Most women reduce their coffee consumption in the early stages of their pregnancy because they develop a dislike for the taste of several dietary items that they previously enjoyed , following hormonal changes. Pregnant women do break down caffeine more slowly, and heavy caffeine consumers would be advised to moderate their intake to around 300mg per day – following the advice given by the SCF. Intakes of 300mg/day do not constitute any risk.
Is it true that the caffeine in coffee can help increase levels of alertness and attentiveness?
Yes. Many well-conducted studies demonstrate the beneficial effects of caffeine in coffee on alertness.
Can drinking coffee lead to better work performance?
Yes. As the caffeine in coffee helps enhance alertness and attentiveness, this can lead to better performance at work.
What about mood, I have read somewhere that caffeine improves mood, is this true?
Yes. Caffeine impacts positively on alertness and performance, and this in turn can help elevate overall mood.
Are there any times of day when coffee is more beneficial to alertness than at other times?
The mild stimulation from caffeine can help at any time of day. In particular, research has shown that caffeine is of notable benefit just after lunch when the body’s circadian rhythm is at a low, and also for people on night shift work.
Is it true that coffee can reduce road accidents?
It is well documented that a couple of cups of coffee and a short nap are the most effective method of alleviating driver fatigue. Many road accidents occur as a result of a driver falling asleep at the wheel so yes, coffee may play a role in reducing the number of sleep related road accidents. In the UK, the Department of Transport as part of their THINK campaign advise drivers to pull over, drink a couple of cups of strong coffee and take a 15 minute nap.
Coffee/Caffeine and Sleep
Does drinking coffee before going to bed stop someone getting to sleep?
There are many external factors, including noise, temperature, and discomfort that may affect how long it takes someone to get to sleep. Many people consume caffeinated drinks during the evening and have no problems falling asleep. Some people find that the mild stimulation of caffeine consumed shortly before going to bed delays the time taken for them to fall asleep, anyone who is particularly sensitive to the stimulant effects of caffeine can simply switch to decaffeinated coffee during the evening.
Will caffeine affect the quality of sleep?
This can vary from person to person and it is therefore not appropriate to generalise. Those people who do find caffeinated coffee effects their sleep may prefer to switch to decaffeinated coffee in the afternoon/evening.
Habituation / Addiction / Withdrawl
Addiction is commonly defined as the abuse of a psychoactive substance to the point where it interferes with an individual’s health, economic or social functioning. The abuse is associated with a need for increasing amounts to achieve the same effect. The word ‘addiction’ is frequently misused and habit may be a more accurate description.
No. Enjoying coffee during the day may be described as a regular habit, but in no way should this be confused with being addictive. Coffee drinkers do not need to increase the amount they consume over time, nor do they generally experience problems if they drink less than they are used to for whatever reason, and also coffee drinking does not cause psychosocial effects.
If I stop drinking coffee will I experience withdrawal symptoms?
Some people may experience mild withdrawal like symptoms, such as headache and lethargy, if they suddenly remove coffee/caffeine from their diet. Individuals who gradually reduce their caffeine intake over a couple of days tend not to experience these symptoms.
I know that caffeine can have a beneficial effect on levels of alertness, but do I need to keep increasing the amount I consume over time in order to achieve these benefits?
No. People tend to find a level of consumption that suits them and there is no need to increase the amount consumed to obtain the beneficial effects on alertness.
Is there any evidence to support the claim that coffee drinking is not addictive?
Yes, research was published in 1999 (Nehlig) that showed caffeine did not act on the brain areas responsible for reward, motivation and addiction in the same way as amphetamines and cocaine.
Do any "official" bodies acknowledge that coffee is not addictive?
Yes. The American Psychiatric Association states in its manual that caffeine does not meet those criteria associated with drug abuse. Unlike the pattern of progressive increase in consumption associated with drugs, the level of caffeine consumption easily remains static over long periods of time. Furthermore, individuals reducing their caffeine intake do not exhibit those symptoms of withdrawal that are characteristic of drug dependence.
Coffee Drinking and Fluid Balance
A diuretic is defined as any substance that increases the secretion of urine – put simply this means anything that makes you want to urinate.
How much fluid do I need on a daily basis?
Health professionals recommend at least 1.5 to 2 litres of liquids a day. The basic point is that you should drink enough fluid to replace what is lost.
Why do I need to drink 1.5 to 2 litres of fluid a day?
Fluids have many functions in the body. They act as lubricant for joints and eyes, help to swallow, provide the medium for which most reactions in the body occur and help get rid of waste. Water also helps to regulate body temperature.
The caffeine in coffee is a mild diuretic, but moderate consumption of coffee has no greater effect than that seen with plain water. Decaffeinated coffee contains minimal amounts of caffeine and will therefore also have no greater effect on fluid loss than water.
So will drinking coffee make me dehydrated?
No, coffee is an important source of fluid in the diet and moderate consumption, of 4-5 cups per day for the general population, will have no adverse effect on fluid levels in the body. In fact, experts in nutrition state that coffee can contribute significantly to daily fluid intake.
No, the diuretic effect of coffee in moderate amounts is no greater than water. The British Nutrition Foundation confirms this by stating that you do not need to drink more water to compensate for consuming caffeinated drinks.
If I am on a calorie-controlled diet, can I drink coffee as part of my daily fluid intake?
Absolutely! Black coffee, or coffee with a little skimmed milk and no sugar has virtually zero calories.
Coffee and Diabetes
Can it be concluded, categorically, that coffee protects against diabetes?
At this stage it would not be appropriate to conclude categorically that coffee protects against type 2 diabetes, however, epidemiological research to date strongly suggests a protective effect.
How does coffee protect against diabetes?
The exact cause and effect has yet to be identified. There are several hypotheses and research into the possible mechanism of protection is ongoing at several research centres.
Does all coffee have the same effect?
Both caffeinated and decaffeinated coffee have been shown to be protective against the onset of type 2 diabetes, or to have a beneficial effect on those suffering from the illness. Decaffeinated coffee was associated with a more modest reduction in risk than was caffeinated coffee.
How much coffee would a person need to drink to see a benefit?
Most research papers that have been published on this subject suggest an effect at around three to four cups of coffee per day. The effect is inversely proportional to the number of cups of coffee consumed.
The research that you refer to recorded a modest amount as being 200mg caffeine that is equivalent to two or three cups of coffee.
Is the same true of caffeine in other forms e.g. tea and cola drinks?
The studies that we have access to have looked at caffeine in coffee and also in tablet form, where the effects appear to be similar. We do not have any studies looking at caffeine in tea or cola drinks.
Antioxidants act as a defence against oxidative damage.
Coffee and Antioxidants
Oxidants are active oxygen components that are necessary for normal functioning of the body (oxygen itself) and are part of the body’s own defence system against damaging micro-organisms. They may however cause oxidative damage to biological molecules and have been suggested to contribute to various diseases such as cancers or cardiovascular problems.
What are the sources of oxidants?
Cigarette smoke, air pollutants, radiation and tissue inflammation are all possible sources of oxidants.
The role of an antioxidant is to help reduce oxidation reactions and thus reduce damage to body tissues.
What are antioxidant defences?
Many things, such as vitamin E, vitamin C, Beta-Carotene, other carotenoids, Selenium, Uric acid, and other naturally occurring proteins found in the body.
Are there antioxidants in food?
Yes, many items which make up our daily diet include antioxidant vitamins, for example, oranges, blackcurrants, fruit juices and potatoes and Brussels sprouts are excellent sources of vitamin C. Vegetable oils, cereals, nuts and seeds and eggs are good sources of vitamin E. Fish oils, liver, dairy produce and carrots are prime sources of vitamin A.
Do those foods that contain antioxidants have the same levels?
No, antioxidant levels vary from one food to another and are also dependent on how the food has been processed, stored and cooked.
Does coffee contain antioxidants?
Yes, coffee is one of a number of drinks that contain antioxidants. Antioxidants are also found in tea, cocoa and red wine. Coffee has actually been shown to contain four times as many antioxidants as tea.
Which antioxidants does coffee contain?
Chlorogenic acid (the most prominent) caffeic acid, and melanoidins are all antioxidants found in coffee. N-methylpyridinium, found in coffee, has also been identified as an anti-oxidant.
Coffee and Degenerative Brain Disease
Coffee drinking in moderation, 4-5 cups per day, is perfectly safe for the general population and may confer health benefits. Evidence strongly suggests that coffee does indeed have a protective effect against the development of these debilitating illnesses.
Has it been proved categorically that coffee drinking protects against these illnesses?
No, it would not be appropriate, at this stage, to say categorically that drinking coffee will stop you from developing these illnesses, however the evidence for a protective effect is extremely strong.
How does this effect work?
The exact mechanisms have yet to be identified.
How much coffee do I need to drink to have this effect?
Results vary from study to study, though the majority of studies suggest that a beneficial effect is seen with consumption of three to four cups of coffee a day.
Does any type of coffee have this effect?
It would appear from the studies available that caffeine is the ingredient responsible for the protective effect. As yet there has been little, if any, research looking at decaffeinated coffee.
No. The overwhelming scientific evidence suggests that moderate coffee consumption, of 4-5 cups per day, is perfectly safe for the general population and may confer health benefits.
A degenerative bone disease, which can lead to an increased likelihood of bone fracture, primarily due to calcium depletion. Osteoporosis is known as a ’multi-factorial’ condition, this means that no single factor alone, such as coffee drinking, would cause this condition. The condition arises as a result of several lifestyle factors.
Does drinking coffee lead to bone loss in men and women?
No. Research has shown that coffee drinkers are no more likely to experience bone loss than those who do not drink coffee.
Are women who consume caffeine more likely to develop osteoporosis than those who do not?
No: There is no real evidence to show that coffee drinking women are at an increased risk for osteoporosis.
Does caffeine have any physiological effects on calcium?
Urinary calcium excretion may increase for a few hours after drinking coffee, but this is transitory and quickly returns to pre-caffeine level. Research has shown that caffeine has no bearing on the development of osteoporosis, or on bone mineral density.
Why do some research studies suggest that caffeine consumption is related to bone mineral content or the likelihood of bone fracture?
There are many lifestyle and dietary factors that have either been considered as potentially affecting bone health, or actually known to be related to the likelihood of osteoporosis. However, determining which factors are causal and which are simply markers for detrimental factors can be difficult.
Coffee / Caffeine and Anxiety
I have heard that caffeine, and therefore presumably coffee causes anxiety, is this true?
No. The only research papers that consistently suggest a link between coffee drinking and anxiety are those conduced on patients who have already been diagnosed with anxiety/panic disorders. For the general population caffeine does not cause anxiety.
Should the general population be concerned that caffeine may cause symptoms of anxiety?
No. It has been demonstrated that moderate caffeine consumption does not cause symptoms of anxiety in the general population.
Coffee and Digestive Problems
Is coffee harmful to the stomach?
No. There is no conclusive evidence to suggest that coffee drinking is bad for the stomach.
Does drinking coffee cause ulcers?
No. Research has shown that coffee drinking does not lead to the formation of either gastric (stomach), or duodenal (upper intestinal) ulcers.
Should people who have ulcers stop drinking coffee?
No. There is no need for ulcer patients to stop drinking coffee if they suffer no symptoms from it.
Heartburn is an uncomfortable feeling that occurs when stomach contents, which are naturally acidic, move back up (or reflux) into the oesophagus. The lining of the oesophagus is sensitive to acid and this results in characteristic feelings of heartburn.
Sometimes when I drink regular or decaffeinated coffee I get heartburn, why is this?
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 else which causes these symptoms.
Does coffee cause heartburn in everyone?
No. The majority of people happily drink coffee, either regular or decaffeinated, and do not experience heartburn. A few people are particularly sensitive to a variety of foods and beverages, and may have minor gastric dysfunction and this leads to the uncomfortable feeling.
If I think that coffee is causing my heartburn should I give up drinking it?
It may be that it is not the coffee that is causing the heartburn but other aspects of your diet. Of course, you could stop drinking coffee and see if this has an effect, in the same way that you could stop eating/drinking other things that may trigger your heartburn.
I have heard that coffee makes the stomach produce too much acid, could this be what is causing heartburn?
Some research has shown that coffee makes the stomach produce more acid, whereas other research shows that even people who are sensitive to coffee produce no more stomach acid than unaffected people. There is no conclusive evidence to suggest that drinking coffee results in abnormally high acid secretion. Many beverages, including fizzy drinks and even milk, which are recommended to ulcer patients, make the stomach produce acid. This does not mean they are harmful.