A coffee myth?

Posted on June 9th, 2010 by Jim

It appears that coffee addicts are merely staving off the effects of caffeine withdrawal they’re no more alert than people who regularly do without The millions of people who depend on a shot of coffee to kickstart their day are no more alert than those who are not regular coffee drinkers, say researchers.

A cup of coffee, suggests a study, only counteracts the effects of caffeine withdrawal that has built up overnight.

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“Someone who consumes caffeine regularly when they’re at work but not at weekends runs the risk of feeling a bit rubbish by Sunday,” said Peter Rogers, who led the research at Bristol University. “It’s better to stick with it or keep off it altogether.”

Infrequent coffee drinkers who reach for an emergency hit fare no better, experiencing heightened feelings of anxiety – and withdrawal symptoms the next day.

How genetic differences may influence response was also examined. Blood samples were taken from 379 volunteers who were asked to avoid caffeine for 16 hours.

After that period, they were given either a caffeine pill or a placebo. Later, they took a slightly higher dose or another placebo. The researchers then used a standard questionnaire called the Mood, Alertness and Physical Sensations Scales (MAPSS) to measure the subjects’ emotional state and alertness.

The participants’ response to caffeine depended on their normal consumption. Roughly half regularly used medium-to-high levels of caffeine – equivalent to a few mugs of filter coffee a day – while the rest usually had little or no caffeine at all.

Caffeine did not increase the alertness of any group above the levels of non-users who were given the placebo.

But caffeine fiends who were given a placebo after abstaining from coffee for 16 hours felt less alert and experienced worse headaches than those who received their usual dose. Four people had to drop out of the study owing to the severity of their headaches.

Infrequent users had more headaches after taking the caffeine pills, but did not feel any more alert than normal.

Among people who usually consumed little or no caffeine, a dose boosted their anxiety levels. Those participants who had a variant of a gene called ADORA2A, which has been linked to panic attacks, became particularly anxious after a dose of caffeine.

Medium-to-high level caffeine users, however, did not become any more anxious after caffeine, implying that regular consumption helps build up a resistance to its anxiety-inducing effect.

People in this group who were genetically predisposed to anxiety drank more coffee than the rest, suggesting mild feelings of tension might even contribute to their enjoyment of the caffeine buzz.

The research is significant because previous studies into the effects of caffeine have involved far fewer participants. The study has just been published in the journal Neuropsychopharmacology

“It’s an interesting piece of evidence, and a very ambitious study,” said Lorenzo Stafford, a psychologist at the University of Portsmouth. “Getting the DNA samples of so many participants is a huge effort.” — Guardian News and Media

Comments welcomed and why not surprise Harvey for his birthday tonight?

No Responses to “A coffee myth?”

  1. O'DB says:

    Hmm, yea maybe but there’s vast amounts of data showing that long term exposure to caffeine isn’t problematic & indeed caffeine has a number of positive side effects in terms of measurable cognitive functions (alertness, concentration, memory). So this one study is interesting data & needs to be added to the growing bank of data on the physiological effects of caffeine, but bucks the trend for improved cognitive abilities with caffeine vs without.

    I posted a piece on this & the numerous positive effects some months back (you may remember the photos of spider’s webs on different drugs), a consensus over numerous (tens) of studies.

  2. Interesting. I did a post regarding the pros and cons. I’ll I know is that I am addicted to coffee since I was fifteen. Can’t miss a day and need a certain amount or feel sluggish or have a headache. During one of my hospitalizations last year, I was diagnosed with yet another diagnosis…caffiene withdrawl.

    By the way, instant coffee is only good if you are really desperate!!! Taste like dirt, but I do remember instant coffee commercials…no look at us!!!
    .-= Clinically Clueless´s last blog ..Homosexuality: Facts and Sterotypes =-.

  3. Gareth in China says:

    Not sure coffee has ever really had a strong effect on me. I had a spell of drinking lots of it and then stopped almost overnight and did not feel or see any measurable effect.

    I think many people on coffee have the placebo effect whilst some may well have an increased sensitivity to it.

    Do the studies ever take into account that people are widely different. Take alcohol for example. I know some people it turns into violent tossers, others it simply turns into giggling balls of laughter.

    We read too much into research, alsop many times the reasearch is steered by the result the researcher wants. How many times do we see conflicting verdicts on many things? One says its bad, the other says its good, et al.
    We reseasrch everything to death these days and some of it is absolutely pointless and of no real use.
    In these times of austerity why not can half of this and make the elbow pad wearers get a real job.

    • O'DB says:

      haha – ‘elbow pad wearers’. That’s one step on from boffins, nerds, geeks (TM. The Sun).

      If the expt is designed correctly & follows empirical standards & logic, then the researchers’ bias shouldn’t enter into it. Physiology & biological systems are often very complex so confounding, even conflicting results may arise. Couple this to the fact that researchers maybe investigating v different aspects of the same pharmacology (e.g. pharmacology of caffeine may involve measuring alertness or memory formation or any number of physiological processes) & it’s easy to see why many studies may give confusing results.

      As for the need for research into the pharmacology & physiological effects of caffeine i think the case for it is strong: it’s probably the most widely imbibed drug for humans in the world, so personally think anything that defines it’s actions (good or bad) needs to be investigated.

      • Gareth in China says:

        Strange caffeine discussions always seems to be linked to coffee, yet black tea (known as also as red tea in China) also has caffeine content not far behind that of coffee yet you never hear people asking for decaff tea or harping on about risks with tea.
        Is it just because the words coffee and caffeine sound similar?
        Placebo, placebo, placebo?

        I based this on these figures from t’internet.
        Double espresso (2oz) 45-100 mg
        Brewed coffee (8 oz) 60-120 mg
        Instant coffee (8 oz) 70 mg
        Decaf coffee (8 oz) 1-5 mg
        Tea – black (8 oz) 45 mg

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