Every day in the UK, we drink 70 million cups of coffee – consuming a huge amount of the world’s most popular drug, caffeine, as we do so.
The stimulant drug caffeine can have serious effects – with a recent John Hopkins University study into ‘caffeine use disorder’ highlighting effects such as ‘anxiety, jitteriness, upset stomach and tense mood’.
Heavy users trying to cold-turkey from the drug experience ‘headaches, fatigue, and flu-like symptoms.’
There have been recorded cases of fatal overdoses – although most of these involve caffeine powder, sometimes used to cut illegal drugs.
But before you panic, the ‘safe’ level of caffeine consumption is quite high – both for negative symptoms and for addiction.
Advice from the Department of Health has suggested that ‘caffeinism’ – addiction – starts at doses of above 600mg of caffeine per day.
General advice – including from the European Food Safety Authority – is to stick below 400mg of caffeine per day.
In Britain, though, the Food Standards Agency does not set a safe limit, saying it varies by individual.
Here’s a rough figure of how much caffeine is in some popular drinks – although obviously this varies according to how the drinks are made:
Cup of filter coffee – 90mg
Espresso – 80mg
Instant coffee – 75mg
But when it comes to spotting negative symptoms, you may be best listening to your own body.
Gaynor Bussell of the British Dietetic Association says, ‘If you enjoy a cappuccino in the morning then that’s fine, but if you start to get palpitations, you’re running to the toilet or noticing an increase in nervousness and sleeplessness, you should probably cut back your caffeine intake.’
Five cups a day
Many researchers seem to agree that anything up to five cups of coffee per day is a good thing.
In a Reddit AMA this week, Harvard dietary expert Vasanti Malik said, ‘Coffee, provided that it is minimally sweetened with sugar and not loaded with whipped cream can definitely be part of a healthy diet.
‘Coffee whether it’s caffeinated or decaf contains a number of healthful vitamins and nutrients and findings from our studies have shown associations with reduced risk for diabetes, cardiovascular disease and mortality. Benefits are seem up to about 5 cups per day, after that there does not appear to be any additional benefit.’
Researchers from the Harvard T.H. Chan School of Public Health found that people who drank three to five cups per day (decaf or not) had a lower risk of cardiovascular disease, neurological diseases, type 2 diabetes, and suicide.
The study analysed data from large numbers of people over the course of about 30 years – based on food questionnaires about what people consumed, and tracked against death rate.
The researchers analysed data from three large, ongoing studies in America: 74,890 women in the Nurses’ Health Study; 93,054 women in the Nurses’ Health Study 2; and 40,557 men in the Health Professionals Follow-up Study.
Coffee and sleep
Drinking coffee in the evening is probably a bad idea, full stop.
Recent research from the MRC Laboratory of Molecular Biology in the UK found that having a coffee three hours before bed can seriously mess with the ‘circadian rhythms’ which tell us
when to sleep and get up.
The researchers worked with 49 volunteers, who tested caffeine pills in different light conditions to see its effect on their sleep.
They found that the amount of caffeine in a double espresso ‘knocks out’ people’s body clocks by up to an hour.
Coffee and addiction
If you’re drinking more than 600mg of coffee per day – seven or more cups of filter coffee – you could be at risk of withdrawal symptoms.
But if you find it hard to cut down, there is help.
‘Caffeine is the most widely used psychoactive drug in the world,’ researchers from John Hopkins University wrote in the Journal of Consulting and Clinical Psychology.
‘In general, when consumed at low to moderate daily doses, for example 400mg, caffeine is a relatively safe drug that offers some functional, for e.g. staying awake during a long drive, and perhaps health-protective, effects, for e.g. Parkinson’s disease.
‘However, for some individuals, caffeine is capable of causing various undesirable effects and disorders across a wide range of doses, which may warrant limiting its consumption.’
The researchers found that cognitive-behavioural therapy – talking with a therapist – combined with gradual reduction of caffeine, can help.
The study found that of 67 people, most reduced their caffeine consumption by 77% – verified by swab tests.