Too much coffee?

Espresso machine producing strong coffee

Espresso machine producing strong coffee on demand.

We have an expensive espresso coffee machine that produces excellent coffee. As native Northern Europeans we drink large cups of coffee. The other day I took the effort of trying to calculate the amount of caffeine in one cup of coffee. The machine has three coffee choice button (apart from a number of buttons also providing different varieties of coffee with hot milk). They provide a ristretto, an espresso, and a strong coffee with increasing volumes of coffee down the buttons. We use the bottom coffee button with the coffee strength set to high and always press it twice to get a double coffee of 250 mL. Now based on data provided for caffeine content in coffee expressed from an espresso machine averaging about 2,000 mg/L,  the amount of caffeine in the cup can be calculated to be around 500 mg. That is a lot.

The European Food Safety Authority (EFSA) in a recent opinion stated that a cup of coffee with 200 mg of caffeine is fine but daily intake of caffeine should be restricted to 400 mg. We exceed this exposure with only one cup of coffee. What could be the implications?

The detrimental effects

It might not all be good.

I recently had a question about coffee and iron absorption. Looking at a recent scientific report it was clear that coffee inhibit iron absorption. A cup of coffee within an hour of an iron rich meal reduced iron absorption by at least 40%. So it is not a good idea to finish a meal with a cup of coffee in case you suffer from iron deficiency. In this case it probably doesn’t matter that much if the cup contains 200 mg or 500 mg of caffeine.

A late coffee might disturb sleep (Photo: RelaxingMusic).

A late coffee might disturb sleep (Photo: RelaxingMusic).

It is also not a good idea to have a late cup of coffee just before going to bed. Large amount of caffeine can disturb sleep patterns and cause insomnia. On the benefit side, caffeine enhances alertness and mood, and increases performance, but that is probably not what you want when going to bed. This effect is most probably influenced by the amount of caffeine consumed so a 500 mg caffeine cup should definitively be avoided before sleep.

Caffeine may also aggravate pre-existing health conditions such as migraines and heart arrhythmias and it can promote anxiety and panic attacks, especially in high doses and in those with pre-existing anxiety disorders. That doesn’t sound very encouraging except that regular coffee consumption will blunt such effects. And we have our daily dose.

So it might be fine.

The beneficial effects

And there is the other side.

The simple act of drinking caffeinated coffee seems to be able to reduce the risk of colon cancer returning after surgery and subsequent death. A clinical trial examined outcomes in patients with stage III colon cancer who were treated with surgery and various chemotherapies. All 953 patients reported their intake habits for 128 foods, including caffeinated coffee, decaffeinated coffee, and nonherbal tea, during and 6 months after chemotherapy.

The benefit was strongest in the heaviest drinkers of caffeinated coffee. Patients who consumed at least four cups of coffee a day or about 460 mg of caffeine were 52% less likely to have their cancer return or to die than noncoffee drinkers. Patients who drank fewer cups of caffeinated coffee also saw a benefit, but the degree of risk reduction tapered as the average number of cups per day dropped. In other words, there was a dose-response effect.

If you aren’t affected by colon cancer there might be more good news. Various studies in recent years have suggested that coffee protects against the development of breast cancer and skin cancer, and protects against the recurrence or progression of prostate cancer.

Among postmenopausal women, heavy coffee consumption is associated with a lower incidence of estrogen receptor (ER)-negative breast cancer. In a study involving about 6,000 females there was a small decrease of 20% in overall breast cancer risk associated with coffee consumption of more than 5 cups/day compared with 1 or fewer cups/day. However, among the heavy coffee drinkers there was a strong reduction of close to 60% in risk for ER-negative breast cancer.

Coffee might reduce cancer incidence.

Coffee might reduce the risk of some cancers.

Coffee may reduce the risk of developing basal cell carcinoma of the skin, according to new prospective data from more than 110,000 healthcare professionals who participated in two large, surveillance studies. Study participants who drank more than 3 cups of caffeinated coffee a day had a 17% reduction in their relative risk of basal cell carcinoma compared with individuals who drank less than 1 cup per month. However, no association was found between consumption of coffee and either squamous cell carcinoma or melanoma.

Drinking 4 or more cups of coffee a day was associated with a lower risk for prostate cancer recurrence and progression, according to a prospective study of a cohort of 630 prostate cancer patients. The study authors found that men who drank that much coffee daily had a 59% reduced risk for prostate cancer recurrence and/or progression, compared with those who drank 1 or fewer cups per week.

So maybe not too much coffee after all

It all sounds great but note that as prospective and observational studies the findings only reveal correlations and are not proof of causation. There are many such studies with dubious results.

However, being an optimist I think I stick to my daily large cup of coffee and hope for the best, ignoring the EFSA advice for now.

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Give chai a try

Getting too much caffeine from coffee (Photo: Wikimedia)?

Getting too much caffeine from coffee (Photo: Wikimedia)?

Drinking too much coffee and getting the caffeine jitters? You could of course go for boring decaf coffee but it wouldn’t save you from the acrylamide and furan toxins formed in all roasted coffee.

Acrylamide is the subject of a new opinion from the European Food Safety Authority (EFSA) currently under public scrutiny. The draft report is recommending that acrylamide exposure be reduced as much as possible since it is a proven carcinogen in animal experiments. It is impossible to totally eliminate acrylamide from the normal diet, but since it is a numbers game any significant reduction in acrylamide exposure will similarly reduce the risk of developing cancer. EFSA recently published an excellent consumer guide on how to reduce acrylamide exposure.

Furan is another substance that has proven to be a carcinogen in animal experiments. Since furan formation is linked to the development of the coffee aroma it is an intrinsic component of roasted coffee and cannot be avoided.

And just so you know, coffee substitutes might be even more dangerous. According to levels of acrylamide in food reported by EFSA, coffee substitutes based on chicory carried at least three times more acrylamide than ordinary roasted coffee.

Go for exciting chai

You could go for ordinary tea, but why not try the exciting chai with less than a third of the caffeine content of normal coffee. Chai is a centuries-old beverage which has played an important role in many cultures. Although the word chai is simply the Hindi word for tea, it is much more to it. Chai is a flavoured tea beverage made by brewing black tea with a mixture of aromatic Indian spices and herbs. It can be prepared black, with milk, and with or without sugar. Originating in India, the beverage has gained worldwide popularity, becoming a feature in many coffee and tea houses. Although traditionally prepared by a decoction of green cardamom pods, cinnamon sticks, ground cloves, ground ginger, and black peppercorn together with black tea leaves, retail versions include tea bags for infusion, instant powdered mixtures, and concentrates.

There has been a phenomenal growth in the popularity and interest in chai in the Western world over the last decade. As chai has become very common at over-the-counter specialty coffee and tea shops, it is now as easy to order a chai latte as it is a cafe latte or a cappuccino. Many industry analysts are predicting that chai will eventually become as popular and common as coffee is now.

Great variety of spices used


A great variety of spices used in producing chai (Photo: Wikimedia)

Drinking chai is part of life in India and most Indian’s are amazed at all the current fuss in the West. The spices used vary from region to region and among households in India. Traditionally, cardamom is a dominant note, supplemented by other spices such as cloves, ginger, or black pepper; the latter two add a heat to the flavour and the medicinal aspect of the drink. Other spices include cinnamon, star anise and/or fennel seeds.

In Western India, cloves and black pepper are expressly avoided, while the Kashmiri version of chai is brewed with green tea instead of black tea and has a more subtle blend of flavourings including almonds, cardamom, cinnamon, cloves, and sometimes saffron. Other possible ingredients include nutmeg, mace, chilli, coriander, rose flavouring (where rose petals are boiled along with the loose-leaf tea), or liquorice root. A small amount of cumin, also considered a “warm” spice in Ayurveda and traditional Chinese medicine/cuisine, is also preferred by some people. A pinch of turmeric may be added to aid those suffering from a fever.

The warm, aromatic flavours of chai have their roots in ancient Ayurvedic traditions. Ayurveda, meaning “life science” in Sanskrit, is a traditional system of medicine that includes the practice of yoga and the use of healing herbs and spices. It is said that Indian chai produces a warming, soothing effect, acts as a natural digestive aid and gives a wonderful sense of well being.

I tried a Hari Hai Chai

I had the benefit of trying a chai latte curtesy Hari Hai Chai recently. I am not vouching for the health claim aspects but it was difficult to resist a second cup and with so much variety possible it might take many months to explore fully.

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Energy drink binging

A multitude of energy drinks on the market today (Photo: Wikimedia)

A multitude of energy drinks on the market today (Photo: Wikimedia)

Energy drinks have been around for some time but their popularity did not take off until the introduction of Red Bull in 1987. Since then the energy drink market has grown extensively, with hundreds of different brands of varying strength now available. Global energy drinks consumption climbed by 14% in 2011, according to the latest report from food and drink consultancy Zenith International reaching 4.8 billion litres. North America was the leading region, with 36% of global volume in 2011, followed by Asia Pacific with 22% and West Europe with 17%.

According to marketing speak, energy drinks are supposed to provide mental and physical stimulation, and who can object to that kind of kick. They may or may not be carbonated, and generally contain large amounts of caffeine and other stimulants, as well as sugar or other sweeteners, herbal extracts and amino acids. While ordinary soft drinks typically contain around 100 mg caffeine/L, energy drinks often contain three times this amount or more than 300 mg/L.

Energy shots are a specialised kind of energy drink usually sold in small bottles of around 60 ml. They contain the same amount of caffeine as a 250 ml energy drink bottle or more than 1,300 mg/L. Energy shots are the fastest-growing part of the energy drink category. Energy drinks are targeting young people. Approximately 66% of its drinkers are between the ages of 13 and 35 years old, with males making up approximately 65% of the market.

And this is the problem

Although healthy people can tolerate caffeine in moderation, heavy caffeine consumption, through drinking energy drinks, has been associated with serious consequences such as seizures, mania, stroke, and sudden death. It has been suggested that both the known and unknown pharmacology of various ingredients in energy drinks, combined with reports of toxicity, may put some children at risk for serious adverse health effects.


High energy drink consumption at discos (Photo: Jirka Matousek)

A German survey of high energy drink consumers in discos and at music and sports events found that some people down as much as five litres of the caffeine-loaded drinks in the space of 24 hours. On average, the clubbers and disco dancers said they consumed a litre of energy drinks in combination with alcohol with most drinkers at such events ignoring health warnings. The highest exposure levels were found among gatherings of computer geeks and video gamers, with non-stop sessions lasting up to 48 hours.

Dangerous adverse health effects

Excessive amounts of caffeine can cause very unpleasant and even life-threatening adverse effects. Although it is possible to die by consuming too much caffeine, it is difficult. The lethal dose has been estimated to be between 3-8 g, which is roughly equivalent to 30 to 80 cups of coffee in a day, but such doses are more likely to be the result of excessive intake of caffeine-containing stay-awake pills or very high volumes of energy drink consumption. Death results from convulsion and respiratory collapse.

The American Association of Poison Control Centers received reports of around 46,000 cases of caffeine poisoning between 2006 and 2008 of which 45 had life threatening symptoms. The number of emergency department visits involving energy drinks among patients 12 years of age or older increased from 10,068 in 2007 to 20,783 in 2011. The Adverse Event Reporting System run by the U.S. Food and Drug Administration collects reports about adverse health events and product complaints including for energy drinks classified as dietary supplements. A summary of adverse effects for energy drinks under the labels 5-Hour Energy and Monster between 2004 and 2012 lists thirteen deaths linked to 5-Hour Energy consumption and five deaths linked to Monster drink consumption.

Occasional death (Photo: Amanda Slater)

Occasional deaths seen after excessive energy drink consumption (Photo: Amanda Slater)

In 2008 energy drinks were granted marketing authorisation in France. In 2009 this was accompanied by a national nutritional surveillance scheme which required national health agencies and regional centres to send information on spontaneously reported adverse events to the French agency for food safety. During the 2009 to 2011 period 257 cases were reported to the agency, of which 212 provided sufficient information for food and drug safety evaluation. The experts found that 95 of the reported adverse events had cardiovascular symptoms, 74 psychiatric, and 57 neurological, sometimes overlapping. Cardiac arrests and sudden or unexplained deaths occurred in at least eight cases, while 46 people had heart rhythm disorders, thirteen had angina and three had hypertension.

Time for action?

Harmful health effects from energy drinks are especially likely when people drink large quantities of them mixed with alcohol, combined with a lack of sleep and physical exertion. Warnings seem to be useless. Maybe it is time to take some further regulatory action?

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How much coffee in your coffee?

A cup of coffee to raise the spirit.

A cup of coffee to raise the spirit.

A bit cryptic I agree and the question should rather be how much caffeine do you think you have in your cup of coffee? But since you have no way of measuring that, unless you have access to a chemical laboratory, you can only control the amount of coffee beans you use for your cup of coffee and the brewing method. And you can use those measures as a proxy for the amount of caffeine you consume.

Why worry about the amount of caffeine?

Because the European Food Safety Authority (EFSA) has just published an opinion on caffeine and alertness. This new opinion confirmed that at least 75 mg of caffeine is necessary to improve alertness. For some reason SmithKline Beecham Limited wished EFSA to agree that 40 mg of caffeine would have the same effect. But EFSA didn’t budge. EFSA was clear in saying that

at the particular dose range between 40 and < 75 mg, no effect of caffeine was found on the majority of outcome measures of reaction time

after reviewing a number of studies submitted by the applicant.

The EFSA scientists also believed that

“increased alertness might be a beneficial physiological effect”

and I assume we all take that for a given. So there you have it, your cup of coffee needs to contain at least 75 mg of caffeine to wake you up.

How to get enough caffeine in your cup of coffee?

As a rule of thumb it’s usually presumed that a regular cup of coffee contains 100 mg of caffeine but it may range between 40 and 176 mg and to be honest the mean is probably closer to 80 mg. This will fit with the standard recipe when calculating exposure of 7 g of ground coffee beans for a cup, which would result in close to 80 mg of caffeine in the cup since arabica coffee beans contain about 11 mg/g. So far so good and we would be over the magical 75 mg caffeine alertness level.

But remember that we haven’t yet looked at the volume of coffee in the cup. The size of a cup can vary from as little as 25 mL (Greek coffee) to a large cup of 330 mL and in extreme cases up to 480 mL for a Starbucks Pike Place cup or a McDonald’s Mocha Frappe. The volume of coffee in an average cup in Europe is actually 120 mL, while in the USA it would be closer to 240 mL.

Large variations in the size of a cup of coffee (Photo: akatori)

Large variations in the size of a cup of coffee (Photo: akatori)

So how does the volume of coffee influence the caffeine level? As it happens not that much since we seem to keep the caffeine level fairly constant for a cup irrespective of size. An Italian espresso of 30 mL would still contain a minimum of 40 mg of caffeine and could be close to the 75 mg mark. This is strong coffee but might be a little low in caffeine to reach the EFSA benchmark. On the other end of the spectrum is a typical 240 mL American cup of coffee that might not hold more than 95 mg of caffeine. Not so strong I would say, no offence intended, but well over the desired level if you drink it all. Even the large McDonald’s Mocha Frappe of 480 mL limits the caffeine to 125 mg per cup, but Starbucks Pike Place is not so restrictive offering 330 mg of caffeine per 480 mL cup.

Confused again?

Well I have to confuse you even more because tastes are different and brewing methods abound. If you go for robusta coffee and use the same amount of beans as for arabica you would double your caffeine intake.

You might think that a strong, rich flavour would indicate an extra dose of caffeine, but the truth is that light roasts actually pack more of a jolt than dark roasts. The process of roasting burns off some caffeine.

And finally, while the caffeine concentration in a normal brew of filtered coffee would amount to 0.6-0.8 mg/mL, it would be 1.7-2.3 mg/mL in the coffee expressed from an espresso coffee machine. But you would obviously pick the size of your coffee cup accordingly to not overindulge.

All I can say is that if you feel alert you have probably exceed the 75 mg of caffeine required to improve your reaction times. Good on you, you will get through the day at your peak.

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Better brainwaves on the loo

Coffee consumption might be beneficial after all (Photo: uzagaku – Flickr)

Apologies for the association, but this post is about a possible diuretic that potentially might improve your brain function according to recent research. We are talking about the assumed effects of consuming coffee and similar beverages. You would have thought that by now the effects of caffeine and related methylxanthine compounds on the human body would be clear. But there are still conflicting opinions in the literature. From mainly negative reporting of gastric ulcers and cardiovascular disease, the situation changed when in 2008 a Harvard-led study reported finding no detrimental effects of consuming up to six cups of coffee a day using 130,000 study subjects.

Coffee consumption

Caffeine, with the full chemical name of 1,3,7-trimethylxanthine, and the related methylxanthines theobromine and theophylline, can be found naturally in the leaves, seeds, and fruits of more than 60 plants, including coffee, tea leaves, kola nuts, guarana, and cocoa beans. Coffee is one of the most widely consumed beverages in the world, and the most commonly consumed psychoactive drug with a production of about 7.4 million tons per year.

The people of Finland are among the biggest coffee consumers in the world. Finns consume an average of 12 kilograms of coffee per capita yearly or 4-5 large cups a day, which is over twice the amount of most other Europeans. Only tiny Luxembourg exceeded this number, with an average consumption of close to 17 kg per year. It might have been expected that countries like Italy or France would be at the top of coffee consumption charts with their famous high quality coffees. However, the French and the Italians only consume an average of 5 kg of coffee per year, slightly higher than the 4 kg in the USA.

Influence on memory

It is clear that caffeine is a psychoactive stimulant drug that influences brain chemistry. It mimics adenosine by binding to adenosine receptors and thus blocking the effects of adenosine, which happens to be to slow down nerve impulses and cause drowsiness. So the brain becomes more alert. Caffeine also increases the levels of dopamine in the brain, which improves the feeling of well-being and mood. But what about memory? Here it is not so clear with studies of short-term and long-term memory showing positive, negative, and no effects at all. The research consensus seems to indicate a slight overall inhibitory effect, reducing the capacity of our short-term memory and working memory. Bad luck!

Improved performance in the elderly (Photo: Lucia Whittaker – Flickr)

However, the situation is much more positive for the elderly. For most older adults, memory performance depends on the time of day, with performance being optimal early in the morning and declining during the late afternoon hours. In a study by Ryan and co-workers from the University of Arizona, adults over the age of 65 who considered themselves “morning types” were tested twice over an interval of 5 to 11 days, once in the morning and once in the late afternoon. Participants consumed either coffee with caffeine or decaffeinated coffee at both sessions. Participants who consumed decaffeinated coffee showed a significant decline in memory performance from morning to afternoon. In contrast, those who consumed caffeine showed no decline in performance from morning to afternoon. The results suggested that time-of-day effects may be mediated by nonspecific changes in the level of arousal.

And the diuretic effects?

review of the available literature suggests that acute consumption of 250-300 mg of caffeine, or 2-3 cups of coffee, results in a short-term stimulation of urine output in individuals who have been deprived of caffeine for a period of days or weeks. However, regular coffee consumption quickly leeds to a tolerance and the diuretic effect is much diminished. But we shouldn’t forget the detrusor muscles in the bladder that help determine capacity limits and outputs and might deteriorate with age. Caffeine happens to relax detrusor muscles causing an urgency to urinate. This indirectly compounds the diuretic effects of caffeine. So it might be that the title is correct after all for the elderly.

But there is more

And in even better news, in 2009 researchers in Finland and Sweden reported results from a study that followed over 1,400 people over 20 years, and found that those who drank 3 to 5 cups of coffee a day in their midlife years had a 65% lower chance of developing dementia and Alzheimer’s disease compared with those who reported drinking no coffee at all or only occasionally. This was supported when researchers from the University of South Florida and the University of Miami, published a paper in June 2012 describing how they monitored the memory and thinking processes of 124 people, aged 65 to 88, and found all those with higher blood levels of caffeine (mostly from drinking coffee) avoided the onset of Alzheimer’s disease in the following four years. The same researchers had previously shown that caffeine consumption could reduce blood levels of the beta-amyloid protein that forms into plaques in the brains of people with Alzheimer’s.

Caffeine can hinder degenerative brain changes (Photo:alles-schlumpf – Flickr)

Further, a research team led by Professor Freund from the University of Illinois suggested that caffeine consumption could help to ease cognitive decline and lower the risks of developing Alzheimer’s disease by blocking inflammation in the brain. The team found that mice given caffeine had lower inflammatory markers and recovered the ability to form memories after hypoxia 33% faster than those not given caffeine.

For Parkinson’s Disease, another neurodegenerative disorder, it appears there is also a link between higher coffee consumption and decreased risk. And like Alzheimer’s, this also seems to be due to caffeine, but it is less clear how it works. One study from the University of North Dakota in the USA, suggested that it might be due to an effect of caffeine that preserves the blood-brain-barrier. The findings were supported by a meta-analysis of 26 studies that suggested an inverse association between tea drinking and the chance of developing Parkinson’s disease. For every increase of 300 mg per day in caffeine intake, they found a drop of 24% in the relative risk of developing Parkinson’s.

Possible health claims

The European Food Safety Authority (EFSA) has received several health claims in relation to products containing caffeine. It has rejected claims that cocoa can enhance mood and that black tea can help focus attention because of insufficient evidence presented. However, claims in relation to what was summarised as alertness and attention after consumption of coffee, guarana or caffeine got the thumbs up by the EFSA Panel on Dietetic Products, Nutrition and Allergies. First the Panel considered that increased alertness and increased attention might both be a beneficial physiological effects. Then, in weighing the evidence, the Panel considered that there was good consensus on the role of caffeine in increasing alertness, measured as speed of reaction times, and increasing attention, measured by a range of psychometric tasks, in healthy individuals of both sexes, at doses of at least 75 mg.

On the basis of the data presented, the Panel concluded that a cause and effect relationship has been established between the consumption of caffeine and increased alertness and attention. In order to bear the claim, a product should contain at least 75 mg caffeine per serving. However, the Panel could not refrain from issuing a warning that for children consumption of a dose of 5 mg/kg body weight could result in transient behavioural changes, such as increased arousal, irritability, nervousness or anxiety. In relation to pregnancy and lactation, they stated that moderation of caffeine intake, from whatever source, is advisable.

So how much coffee do you need?

Two daily cups of coffee might be enough (Photo: antwerpenR – Flickr)

It is quite difficult to figure out how much caffeine is consumed from a regular cup of coffee. Cup sizes differ from country to country. For instance, in the USA, coffee is typically served in a 240 ml cup, which is twice the amount of a typical European serving. The caffeine concentration also varies depending on the beans, how they are roasted, and how the coffee is prepared. A restaurant-style serving of Espresso in a 30ml cup can contain from 40 to 75 mg of caffeine. Even a decaffeinated Espresso can contain up to 15 mg of caffeine.

On the other hand, a 240 ml cup of generic instant coffee can contain any amount from 27 to 173 mg of caffeine, while a Starbucks Pike Place 480 ml cup of brewed coffee contains 330 mg of caffeine. A moderate intake of caffeine is probably around 300 mg per day. This is roughly 3 to 4 cups of ground roasted coffee or 5 cups of instant coffee. So 1-2 cups of coffee a day should easily qualify for the health claim.

By the way, tea has about half as much caffeine as coffee in case you are a tea drinker.

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