To those who never read about my coffee drinking habits and my favourite Starbucks beverages, let me say this, I am a coffee drinker who also loves Teh Tarik. There are many articles written about coffee whether leisurely or academically, and most points towards the benefits of coffee-drinking habits.
Yet, I am compelled to read more about these so-called ‘benefits’ because my wife has a habit of chanting this mantra to me whenever she believes I have had too much coffee : ‘caffeine is like a mild steroid – taken a little bit will excite the brain, but too much can kill the body’.
Too slanderous, perhaps?
All I know is, based on my personal experience, a cup of coffee in the morning is a great pick-me-up but more than 1 cup of coffee drank during the day would cause my brain to be hyperactive until late in the evening, therefore I couldn’t focus on activities that requires high mental concentration but good for activities that involves physical exertion.
As for my wife, she swears that a cup of Nescafe is stronger than most other coffee.
Coffee And Health
Not being a scholar, a Food Science graduate nor a Dietician, I scoured the internet for some light on this issue. I came across a paper ‘Effects Of Caffeine On Human Health’ prepared by P. Nawrot, S. Jordan, J. Eastwood, J. Rotstein, A. Hugenholtz and M. Feeley (Toxicological Evaluation Section, Chemical Health Hazard Assessment, Division, Bureau of Chemical Safety, Food Directorate, Health Canada, Tunney’s Pasture, PL 2204D1, Ottawa, Ontario, Canada K1A 0L2).
You can read the paper HERE.
Again, not being a scholar, a Food Science graduate nor a Dietician, I am trying very, very hard here not to summarize the paper nor make any conclusions.
All I endeavour to do here is share and highlight some parts of the paper that I find interesting. Such as:
Following ingestion, caffeine is rapidly and essentially completely absorbed from the gastrointestinal tract into the bloodstream. Maximum caffeine concentrations in blood are reached within 1–1.5 h following ingestion. Absorbed caffeine is readily distributed throughout the entire body. It passes across the blood–brain barrier, through the placenta into amniotic fluid and the foetus, and into breast milk. Caffeine has also been detected in semen (Berger 1988, Arnaud 1999).
Now, isn’t that interesting? Foetuses and babies of coffee drinking dads and moms have been taking in caffeine even before they start to drink pure water!
Excessive Caffeine Ingestion
Death due to excessive caffeine ingestion is not common, and only a few cases have been reported in the literature. The acute lethal dose in adult humans has been estimated to be 10 g/person. Death has been reported after ingestion of 6.5 g caffeine, but survival of a patient who allegedly ingested 24 g caffeine was also reported (Stavric 1988, James 1991b).
Of course, the same can be said of roti canai, sugar, etc, when taken excessively.
So, what is the proposed safe limit?
According to the said paper, depending on the method of preparation, the product brand, the strength and type of coffee, the size of the serving cup and the health conditions of the drinker, the following was the suggestion:
In summary, the data currently available indicate that moderate caffeine intake (four or fewer cups of coffee per day, or less than 400mg caffeine day_1) does not adversely affect cardiovascular health. There are insufficient epidemiological data to draw any conclusions about the risk for coronary heart disease or mortality associated with consumption of 10 or more cups of coffee per day (more than 1000 mg caffeine day_1).
Phew! What a relief for me! 4 cups of coffee a day is the most that I can get away with anyway.
Caffeine In Coffee Is Not Responsible For Cardiovascular Effects
None of the epidemiological data determine whether it is caffeine per se or other components of coffee that are responsible for coffee’s association with cardiovascular disease.
Although no significant association has been found between tea consumption and cardiovascular disease (Franceschi 1993, Thelle 1995, Myers 1998), it has been suggested that the beneficial effects of the flavonoids present in tea may offset any adverse effect of caffeine (Thelle 1995).
Support for the idea that caffeine in coffee is not responsible for cardiovascular effects comes from epidemiological studies showing an increased risk of coronary events with consumption of decaffeinated coffee (Grobbee et al. 1990, Gartside and Glueck 1993).
What is the purpose of drinking decaffeinated coffee? It’s like eating mock beef, I guess.
A mere substitute.
It is now widely believed that habitual daily use of caffeine >500–600mg (four to seven cups of coffee or seven to nine cups of tea) represents a significant health risk and may therefore be regarded as ‘abuse’.
Sustained abuse may in turn result in ‘caffeinism’, which refers to a syndrome characterized by a range of adverse reactions such as restlessness, anxiety, irritability, agitation, muscle tremor, insomnia, headache, diuresis, sensory disturbances (e.g. tinnitus), cardiovascular symptoms (e.g. tachycardia, arrhythmia) and gastrointestinal complaints (e.g. nausea, vomiting, diarrhoea) (James and Paull 1985).
Excessive caffeine intake (>400 mgday_1) may increase the risk of detrusor instability (unstable bladder) development in women. For women with pre-existing bladder symptoms, even moderate caffeine intake (200–400mg day_1) may result in an increased risk for detrusor instability (Arya et al. 2000).
In summary, the moderate consumption of caffeine in normal adults has not been associated with any major adverse effects on mood or performance, and most effects associated with higher consumption rates would be self-limiting. However, in light of inconsistent results in the literature and individual differences in sensitivity to caffeine, some people (e.g. those with anxiety disorders) need to be aware of the possible adverse effects of caffeine and to limit their intake accordingly.
I have seen some whose fingers quiver though they were not nervous or cold. Some said that withdrawing from coffee has stopped the quivers and then when they resume a minimum intake of caffeine (about a cup of coffee a day), the quivers did not reappear.
Effect Of Coffee On Pregnant Women
The evaluated epidemiological studies generally indicate that consumption of caffeine at dose levels of >300mg day_1 may reduce fecundability (the ability to conceive in a menstrual cycle) in fertile women…. there appear to be reasonable grounds for limiting the consumption of caffeine to <300 mgday_1 in women who are, or who are planning to become, pregnant.
So, to ladies who plans to conceive and to those who are newly pregnant, this suggests that you limit your caffeine (coffee, tea, soft drinks) intake to only 2 cups daily.
Based on the above evaluated data, despite inconsistencies in the results, it is concluded that caffeine consumption during pregnancy at dose levels of 300mgday_1 may interfere with foetal growth (decrease in birth weight or intrauterine growth retardation), particularly in smokers or heavy alcohol drinkers.
I believe the possibilities are there, those cases are very, very rare and based on the overall facts of a case.
Based on the data reviewed, it can be concluded that there is ample evidence indicating that for the general population of healthy adults, moderate caffeine intake at a dose level of 400mg day_1 is not associated with adverse effects such as general toxicity, cardiovascular effects, changes in adult behaviour, increased incidence of cancer and effects on male fertility.
Nor are moderate intakes of caffeine associated with adverse effects on bone status and/or calcium balance if adequate intakes of calcium are being consumed. Data have also shown that reproductive-aged women can be defined as an ‘at risk’ group who may require specific advice on moderating their caffeine intake.
It is therefore recommended that caffeine intake for women who plan to become pregnant and for women during gestation should not exceed 300mgday_1, equivalent to 4.6mg kg_1 bw day_1 in a 65-kg person.
In a way, my wife’s mantra is not wrong, as stated in the above. But as usual in most things in this universe, moderation is the key to stability.