Doctors warn over shocking side-effects of consuming too much caffeine, and believe too many people maybe addicted to the stimulating drug…
Scientists have claimed that, like methadone users, those who feel they cannot function without a morning coffee may be trying to “stave off withdrawal symptoms”.
Scientists also claim caffeine stimulates the brain in the same way as amphetamines, cocaine and heroin and could be classified as an addictive drug.
The British are notorious for drinking to excess, but could excessive consumption of caffeine – ‘the world’s most popular psychoactive drug’, found in coffee, tea, soft drinks and some medicines – lead to more than an occasional bout of insomnia?
Caffeine (the chemical 1, 3, 7-trimethylxanthine) is found in a range of plants, of which coffee is the best known natural source.
According to historian Mark Diller, caffeine was discovered by Ethiopian shepherds who noticed that eating coffee berries had a stimulating effect on their herd.
Fourteenth Century Arabs were the first to produce a rudimentary cup of coffee by separating the coffee bean from the berry, crushing it and mixing the grounds with water to produce kahveh.
The Arabs retained firm control of the coffee bean trade for several centuries; anyone caught smuggling a live coffee seedling faced execution.
As stories of the ‘wine of Araby’ spread, distrustful Europeans branded it the brew of Satan, while priests urged their flock to resist this immoral drink.
Finally in 1600, the Pope himself endorsed coffee and it began to lose its stigma among god-fearing citizens; though the rulers of Imperial Russia still considered it a deadly poison.
By the late 1800s, the Dutch had succeeded in planting stolen coffee seedlings on the islands of Java and Sumatra and a cutting taken from a coffee plant, given as a gift to the king of France, fathered the coffee plantations of Central and South America.
Since boiling water killed bacteria and the caffeine gave drinkers an alertness boost, coffee grew in popularity and coffeehouses sprung up across newly-industrialised Europe.
Harvard Medical School neuroscientist, Charles Czeisler, says when the nature of people’s work changed from working around the sun to an indoor job timed by a clock, humans had to adapt.
“The widespread use of caffeinated food and drink – in combination with the invention of electric light – allowed people to cope with a work schedule set by the clock, not by daylight or the natural sleep cycle,” believes Czeisler.
Fast-forward to today and American coffee giant Starbucks, which boasts 443 branches throughout the UK; including eight in central Glasgow.
Whether it’s a double shot of redeye or half-pint macchiato, customers are queuing up for their much loved caffeine jolt.
If sleep is creeping up during a late-night revision session, reach for the Red Bull or a caffeine supplement like Pro-Plus; the latter boasting 50mg of pure caffeine in every tablet.
Second year pharmacy student, Joe Grady, who has two or three cups of coffee a day, doesn’t believe he is dependent, but definitely agrees a caffeine boost helps.
“I tend to be ok without it, but it’s become a routine for me,” says Grady.
He also admits to drinking several cans of caffeinated soft drink in an average week.
Caffeine keeps us awake by blocking the effects of the chemical adenosine, which causes us to feel sleepy.
Adenosine attaches to receptors in the brain and slows down the activity of nerve cells.
Caffeine attaches itself to the same receptors: blocking adenosine, increasing brain cell activity, and producing the buzz obtained from drinking a caffeine-laced brew.
The amphetamine connection lies in the effect caffeine has on dopamine, a neurotransmitter (another brain chemical).
Both caffeine and amphetamines increase dopamine levels – cocaine and heroin work by inhibiting the rate of dopamine re-absorption – giving a brief boost in energy and mood.
This increase in dopamine is also thought to encourage addiction.
The caffeine affect has been “demonstrated both at high doses [and] more realistic lower doses,” writes D Warburton in the journal of Psychopharmacology.
“It has been shown that the effects are due to caffeine itself rather than the combination of caffeine and the drink in which it is presented,” notes A Smith in health journal Human Psychopharmacology.
However, research suggests that, after the initial buzz, caffeine may lead to a decrease in energy levels and an increase in anxiety.
In the journal Electroencephalography and Clinical Neurophysiology, M Lorist and J Snel write: “Several cups of coffee each containing 125mg of caffeine [roughly four cups, according to the FSA] increased anxiety. ‘Caffeinism’ has been described as a group of symptoms… which closely resemble the symptoms of severe chronic anxiety.”
Coffee manufacturers dispute this, stressing that “normal doses of caffeine” do not appear to increase anxiety.
Caffeinated energy drinks, popular as vodka mixers, can contain as much as 80mg of caffeine – and plenty of sugar – per can.
Red Bull, which recorded sales of 1.5 billion cans worldwide in 2003, also lists taurine (an amino acid originally derived from ox bile) and glucuronolactone.
Little is known about this substance, but the EC has stated that both it and taurine should be researched further.
Following several unexplained deaths in 2001, Sweden’s government warned people not to mix Red Bull with alcohol.
This warning was later admitted to be a precaution, as no link to the deaths could be proven.
Caffeine is not only available in liquid form.
Gordon, a 21-year-old marketing student, recently took 10 Pro-Plus tablets – which contain 50mg of caffeine and are sold in multiples of 24 – in one day to help him stay awake while writing his dissertation.
The manufacturer warns users not to take more than 12 tablets in 24 hours; equivalent to 600mg of caffeine or six cups of strong coffee.
Described as an “over the counter”, non-prescription medicine, only one of three local pharmacists contacted said they would restrict sale of the drug.
Packets of the tablets are also available to order online (in apparently unrestricted quantities) from Boots the Chemist and Asda.
So what’s the risk? High levels of caffeine can be toxic: an overdose of caffeine tablets, like Pro-Plus, could cause vomiting, unconsciousness or death.
There’s also evidence to support the addiction theory.
Caffeine withdrawal symptoms can include headaches, nausea and could even pass for a dose of flu, says Baltimore neuroscience Professor Roland Griffiths.
Neuroscientist Charles Czeisler highlights one side effect of caffeine that many students cannot seem to escape: lack of sleep; a problem exacerbated by a caffeine-rich diet.
“Caffeine helps people try to wrest control away from the human circadian rhythm that is hardwired into all of us,” said Czeisler.
“As a society, we are tremendously sleep deprived”, he continues, adding: “We use caffeine to make up for a sleep deficit that is largely the result of using caffeine.”