Counterbalancing health effects of coffee consumption

coffee4If you’re an avid coffee consumer you must have been delighted to see in the news lately that coffee can have beneficial health effects. Coffee had previously confusingly been in the bad books blamed for everything from stunting growth to causing heart disease and insomnia.

It had also been shown that high consumption of unfiltered coffee (boiled coffee popular in Scandinavian countries or espresso invented in Italy and spread all over the world) fails to catch a compound called cafestol in the oily part of coffee that can increase the bad cholesterol or LDL.

Not so good.

So what changed?

The good news was based on a scientific review aimed to dispel some of that confusion, examining the evidence presented in 218 previous studies. It’s an example of the ever more popular meta-analysis of existing research that by combining previous findings strengthen the proof of the conclusions.

In synthesising the reported findings the researchers found that coffee consumption was more often associated with benefit than harm for a range of health outcomes across exposures. Three to four cups a day seemed to be optimal.

Drinking coffee was consistently associated with a lower risk of death from all causes and a lower risk of several cancers, as well as type 2 diabetes, gallstones and gout.

Liver conditions, such as cirrhosis, saw the greatest benefit associated with coffee consumption. There also seemed to be beneficial associations between coffee consumption and Parkinson’s disease, depression and Alzheimer’s disease.

Overall, there was no consistent evidence of harmful associations between coffee consumption and health outcomes, except for those related to pregnancy and for risk of fracture in women.

Spoiling the good news story

We shouldn’t spoil a good news story, but we have previously mentioned the presence of toxic acrylamide and furan especially in coffee. Now the European Food Safety Authority has published a new opinion on furan confirming the previous suspicion that furan in food could be harmful to health. Based on animal studies they concluded that liver damage and liver cancer are the most critical health effects.

Although the average intake of food containing furan indicates a low health concern for most consumers, for high consumers exposure is up to three times what would be considered of low concern for public health.

The most exposed group of people are infants, mainly through consumption of ready-to-eat jarred or canned foods. Exposure in other population groups is mainly from consumption of grain-based foods and, here you have it, coffee, depending on age and consumer habits.

coffee_beans_(MarkSweep)The highest concentrations of furan were found in whole roasted coffee beans, with a mean value of 4,579 µg/kg. High mean concentrations of furan were also found in ground roasted coffee (2,361 µg/kg) and instant coffee powder (310 µg/kg). This should be compared to mean values ranging from not detected to 57 µg/kg for most other foods.

All is not lost

There is a serious anomaly between the observational findings that coffee consumption is associated with a lower risk of liver damage, while on the contrary animal studies link the presence of furan in the diet to liver damage. And coffee provides the highest exposure to furan in adults.

What’s to give?

As bad as the concentrations of furan seem to be in solid coffee samples, in preparing the coffee beverage there is both a dilution and an evaporative loss of furan down to typical concentrations of about 60 µg/L in the final beverage. Still bad for heavy coffee drinkers.

But there is more.

Coffee contains a complex mixture of bioactive compounds benefiting health.

It contributes a large proportion of the daily intake of dietary antioxidants, greater than tea, fruit, and vegetables. Chlorogenic acid is the most abundant antioxidant in coffee; though it is degraded by roasting, alternative antioxidant organic compounds are formed. Caffeine also has significant antioxidant effects.

Cafestol and kahweol induce enzymes involved in carcinogen detoxification and stimulation of intracellular antioxidant defence, contributing towards an anticarcinogenic effect.

These antioxidant and anti-inflammatory compounds are likely to be responsible for the  beneficial associations between coffee consumption and liver health, and might neutralise the effects of furan.

coffee drinker

You can still drink your coffee with peace of mind

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The intricate effects of coffee on human health

The details of what we eat is not easy to capture (Photo: Christina Roervik)

The details of what we eat is not easy to capture (Photo: Christina Roervik).

I know, most often on this blog we don’t put much value on epidemiological studies linking disease over decades to food consumption captured by a one-time limited food frequency questionnaire at the beginning of the study period. Knowing the limited reliability of such a food consumption method, intricate relationships between different food groups and changes in food consumption patterns with increasing age it is surprising that it is even called science. But this time it might be different (or is that wishful thinking from our side?).

A new study praises the benefits of coffee

This new epidemiological study of coffee consumption and health is quite elaborate. Firstly, it involved 208,501 participants with 31,956 deaths in three large cohort studies allowing detailed statistical calculations. Secondly, it repeated the food frequency questionnaire each four years to capture food pattern changes. And thirdly, it actually validated the food frequency questionnaire against a multiple week dietary record showing a correlation of 0.74 and reproducibility of 0.80. So a good starting point strengthened by the fact that previous studies have shown that coffee intake is one of the food items showing the highest validity and reproducibility when using food frequency questionnaires and a beverage less prone to misreporting.

Detailed information on caffeinated and non-caffeinated coffee consumption was available as well as other dietary and lifestyle factors. The initial analyses showed a positive correlation between coffee consumption and smoking and because of the deleterious effects of smoking on health, smokers were excluded from the further analyses.

In summary, the good news showed that regular consumption of coffee was inversely associated with risk of total mortality and in particular mortality due to cardiovascular disease and neurological diseases like Parkinson’s. No significant association between coffee consumption and total cancer mortality was found, so unless the International Agency for Cancer Research (IARC) has 799 studies showing the opposite, coffee should be in the clear (I am referring to the dubious nomination by IARC of whole categories of meat or meat products as cancer suspects based on 800 studies we have not yet been able to verify).

Optimal coffee consumption

Three to five daily cups of coffee optimal for health.

Three to five daily cups of coffee optimal for health.

Three to five cups a day seemed to have the optimal protective health effects with the mortality rate 12% less compared to non-coffee drinkers. Similar associations of caffeinated and decaffeinated coffee consumption with risk of total and cause-specific mortality were found. Thus the caffeine is not the protective compound. There are several other compounds in coffee that could be responsible for the positive effects. The authors list chlorogenic acid, quinides, lignans, trigonelline and magnesium as likely contenders as they reduce insulin resistance and systemic inflammation that in turn might prevent diabetes as well as cardiovascular disease.

There could be another reason linked to the dubious findings of IARC and meat consumption. Apart from the obvious culprits associated with meat consumption, like polycyclic aromatic hydrocarbons formed during wood smoking and barbecuing, nitrite added to processed meats and heterocyclic amines formed during high temperature frying, the only compound inherent to meat itself (providing some justification for nominating a whole food category as carcinogenic) is haeme iron. As it happens haeme iron is an excellent source of bioavailable iron, but new research points to excess iron being responsible for a range of human illnesses as well as promoting bacterial growth (in a further blog we will delve into the details of the influence of iron on human health).

Why not try a cup of coffee after dinner?

Now a cup of coffee after dinner inhibits the efficient uptake of iron by the human body. This might be a double whammy in that you can enjoy your red and processed meat without much worry and get an extra kick by the coffee. We told you about the importance of the whole diet with intricate relationships between different food groups.

Maybe IARC should be a bit more careful in the future in looking at individual foods, otherwise it will not be much left to eat. Arsenic in rice cause cancer, too much milk has been associated with prostate and breast cancer, a range of refined and processed foods contribute to weight gain with obesity a factor in cancer development. The list goes on and on. But stick to coffee and you might be fine (although your sleep pattern might be disturbed by a late cup).

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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

chai_tea_(Wikimedia)

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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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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Skip the third cup of coffee – or not

A cup of coffee to raise the spirit.

A cup of coffee to raise the spirit.

Do you need a cup of coffee in the morning like me to start functioning? To kick-start the brain and get the spirit up. Do you also have a refill after lunch? To be honest I am tempted to have a third cup in the afternoon as well, but then I remember the furan issue.

You haven’t heard about furan? Lucky you. If you read on I am going to destroy the enjoyment of your final cup of coffee for the day – or not.

You might have read the previous blog on acrylamide formation in which you had to take most of the blame for this toxic compound found in your toast. With furan it is actually a shared responsibility between you and the coffee roaster unless you roast your own coffee. And not many would do that.

First some technical facts about furan

Furan is a highly volatile substance formed in foods and beverages due to the degradation of naturally-occurring sugars, polyunsaturated fatty acids and ascorbic acid (vitamin C) during heating. It is actually an integral component contributing to the sensory properties of the heated product and is seen as an important coffee flavour component. However, in 2004, the US Food and Drug Administration (FDA) raised concerns about the presence of furan in food and beverages.

Already in 1993 furan was subject to comprehensive toxicological evaluation within the US National Toxicology Program (NTP). Results showed that furan was carcinogenic and mutagenic in animal experiments. High doses of furan given to rats and mice caused the formation of liver tumours. It is also expected to be genotoxic, a particular danger sign, and a warning has been issued that it might be a possible human carcinogen. More research is underway to confirm the previous findings, but overall currently not good news on this front.

Furan levels in coffee

Roasted coffee beans have the highest furan levels (Photo: MarkSweep)

Roasted coffee beans have the highest furan levels (Photo: MarkSweep)

Although furan can be formed in different heated foods and beverages, coffee is the outstanding contributor to furan exposure in adults. A survey by the European Food Safety Authority found that roasted whole coffee beans have the highest levels of furan, followed by roasted ground coffee and instant coffee powder. The darker the roast, the higher the furan levels. So that’s the industry side and it is not much they can do while retaining the coffee aroma.

But as it happens it is also important how you prepare the coffee brew. When Spanish researchers compared the effect of different brewing methods they found the highest furan levels in coffee made from capsules followed by commercial bean-to-cup machines in which the coffee was prepared from start to finish in a largely enclosed environment. Less furan was found in coffee made in drip coffee machines and the least in instant coffee.

There is an easy explanation to the findings. The hermetically-sealed capsules prevent the highly volatile furan from being released, and the coffee machines used to brew this coffee use hot water at higher pressures, which leads to more of the compound being extracted into the brew. Similarly, the enclosed system in automated espresso machines transfers more furan to the final brew. This is great for the coffee taste but may be bad for health.

But there are some good news

Because of the volatility of furan, the longer the coffee brew is exposed to air in cups or jugs the more of the furan will evaporate. So maybe you should let the coffee cool down a bit before drinking it. You might also avoid to take a sniff of the newly brewed coffee though, as good as the smell might be.

And there is more. Confusingly, a recent review of epidemiological data found that three cups of coffee per day actually reduced liver cancer risk by more than 50%. It was speculated that this favourable effect might have been mediated by coffee’s proven prevention of diabetes, a known risk factor for the disease, or for its beneficial effects on cirrhosis and liver enzymes. A further epidemiological study showed that four or more cups of coffee a day was associated with a lower risk of prostate cancer recurrence and progression. Men who drank that much coffee daily had a 59% reduced risk for prostate cancer recurrence or progression, compared with those who drank one or fewer cups per week.

So what to believe? It is proven that coffee contains phytochemical compounds with beneficial effects on health. That include anti-inflammatory and antioxidant effects and modulation of glucose metabolism, but also some anti-cancer effects. Could that weigh up the potential negative effects of furan?

Maybe I should have the third cup of coffee anyway.

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The real kick – coffee-leaf tea!

Tea can be made of coffee leaves (Photo: Wikimedia)

Tea can be made of coffee leaves (Photo: Wikimedia)

Do you get your daily kicks from coffee or tea? Well, don’t worry anymore because now you can have the best of both worlds with coffee-leaf tea. That is if you can find the coffee leaves in your shop, but more on that later.

Coffee leaves are the actual leaves from the coffee plant (either Coffea robusta or Coffea arabica). They can be used to prepare a herbal tea. After being roasted, the leaves are ground up or crumpled, then brewed in hot water  similar to normal tea. The resulting brew has an earthy taste but is otherwise similar to green tea. It contains less caffeine than either regular tea or coffee.

Coffee-leaf tea is so far not a common drink, but has been popular in some regions such as Sumatra and Ethiopia. Called kuti, it was drunk in Ethiopia, centuries before coffee bean roasting was invented. The locals there believe that the drink stems hunger and tends to energise both the body and mind. There have been historic attempts by coffee producers in Sumatra and Java to popularise coffee-leaf tea in the United Kingdom and Australia – it was even displayed in London at the Great Exhibition of 1851 – but the drink did not get enough attention to create a market opportunity.

This situation might change with new findings reported by researchers from the English Royal Botanic Gardens at Kew in London and the French Research Institute for Crop Diversity, Adaptation and Development in Montpellier. The two research teams suggest that tea brewed from coffee leaves may have several health benefits. They discovered that coffee-leaf tea has more antioxidants than regular tea. This is because it contains high levels of the phenolic compounds mangiferin and hydroxycinnamic acid esters credited with lowering the risk of heart disease and diabetes, reducing cholesterol levels and protecting neurons in the brain. Mangiferin is a natural chemical normally found in mangoes while hydroxycinnamic acid esters have been isolated from blackcurrants and a range of vegetables.

Coffee beans the second most valuable commodity (Photo: Wikimedia)

Coffee beans the second most valuable commodity (Photo: Wikimedia)

The researchers believe the leaves of the Coffea genus have been overlooked because of the high value placed on its seeds, the coffee beans, which contain far fewer beneficial compounds. This might be the reason why coffee leaves are not yet widely available, but they can be found in some health food shops. A difficulty for more general adoption might be that coffee growers will want the leaves to stay on their plants so they can produce good beans. Coffee beans are the world’s second most valuable commodity after crude oil, with almost eight million tonnes produced and more than 400 billion cups consumed worldwide each year in an industry worth more than $66 billion.

And some final advice. Before going full bottle with coffee-leaf tea be aware that the researchers point out that more research will be needed to confirm the proposed health benefits.

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Acrylamide – nothing seems to help

French fries a large contributor to acrylamide exposure (Photo: freephotouk)

Acrylamide is a chemical compound that typically forms in starchy foods during frying, baking, roasting and grilling. It is linked to the browning of food during the so called Maillard reactions. The darker the food the more acrylamide seems to be formed. It was found in food by coincidence in 2002 when examining a leak of the industrial chemical polyacrylamide from a tunnelling project in the south of Sweden. It was first thought to be an environmental contaminant. It has since been shown to actually be a process contaminant formed in food during dry heating, but not boiling.

Acrylamide received a lot of attention among scientists and the popular press over the first years of its discovery. Industry started programs to attempt to reduce its formation and household cooking instructions were issued. The toxicity of the compound was explored in more detail.

Toxic properties

The toxic effects of acrylamide in industrial exposure and in smokers have been known for some time and include damage to the nervous system and to male fertility. However, looking at potential food exposure, the Food and Agriculture Organization of the United Nations and the World Health Organization concluded that the levels required to observe such effects was 500 to 2,000 times higher than the average dietary exposure of acrylamide. From this, they concluded that acrylamide levels in food were safe in terms of neuropathy and infertility, but raised concerns over human carcinogenicity based on known carcinogenicity in laboratory animals.

Checking your consumption patterns (Photo: mikeandanna)

Attempts to confirm a cause and effect relationship in humans between acrylamide exposure and cancer is on-going. A number of epidemiological studies have looked at the correlation between acrylamide intake through food frequency questionnaires and a range of different cancers. Many studies proved negative, but there were indications that dietary acrylamide could be associated with the formation of myeloma, head-neck cancer, oesophageal cancer, endometrial cancer and ovarian cancer.

Now there is documentation of a further effect. A new report published on 23 October 2012 described maternal exposure to acrylamide and birth weight of children. A team led by Marie Pedersen from the Centre for Research in Environmental Epidemiology (CREAL), Spain, measured blood levels of acrylamide and its common metabolite glycidamide and found that dietary exposure to acrylamide while pregnant resulted in reduced birth weight and head circumference in the off-spring. The authors pointed to a potentially substantial public-health implication of their findings since reduced birth head circumference has been associated with delayed neurodevelopment.

Attempts to reduce acrylamide formation

Acrylamide forms from sugars and an amino acid (asparagine) during high-temperature processing of plant foods in particular such as potato crisps, French fries, bread, biscuits and coffee. In a report published by the European Food Safety Authority (EFSA) in 2011, fried potatoes (including French fries), roasted coffee and soft bread were identified as the major contributors to acrylamide exposure in adults, while fried potatoes, potato crisps, biscuits and soft bread were identified as the major contributors to exposure in adolescents and children. The exposure estimates for these different age groups in Europe were comparable to those previously reported in scientific literature and in risk assessments carried out by the Joint FAO/WHO Expert Committee on Food Additives (JECFA).

The food industry has been exploring ways of reducing acrylamide levels in foods without reducing desirability and taste, including using lower cooking temperatures and adding enzymes to reduce the amount of acrylamide that forms during cooking. The industry in Europe developed a “tool box” containing advice on how to reduce acrylamide formation.  Many of the recommendations should have been adopted by now. It seems the process changes have had limited success. An EFSA report published on 23 October 2012 showed only very limited changes in acrylamide levels between 2007 and 2010 in most food groups. With some good will slightly reduced acrylamide levels could be seen in some cereal-based foods for children and non-potato savoury snacks but on the contrary  acrylamide seemed to increase in coffee and coffee substitutes, crisp bread and some types of French fries.

What is the consumer to do?

Coffee – to drink or not to drink? (Photo: arimoore)

If the industry is mainly failing in their attempts to reduce acrylamide levels in food what is the consumer to do? We could of course just give up. A more sensible approach would be to be a bit more careful when heating food since acrylamide formation increases with increased heat. If toasting bread, make it only golden brown. Equally be careful with the French fries. Although coffee might delay the development of Alzheimer’s disease, it is also a major contributor to acrylamide exposure. Not an easy choice.

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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