Caffeine addicts get no real perk from morning cup

LONDON Wed Jun 2, 2010 10:59am EDT

Cups of cappuccino sit on a table in Guatemala City in this February 26, 2010 file photo. 	 REUTERS/Daniel Leclair

Cups of cappuccino sit on a table in Guatemala City in this February 26, 2010 file photo.

Credit: Reuters/Daniel Leclair

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LONDON (Reuters) - Caffeine addiction is such a downer that regular coffee drinkers may get no real pick-me-up from their morning cup, according to a study by British scientists.

Bristol University researchers found that drinkers develop a tolerance to both the anxiety-producing and the stimulating effects of caffeine, meaning that it only brings them back to baseline levels of alertness, not above them.

"Although frequent consumers feel alerted by caffeine, especially by their morning tea, coffee, or other caffeine-containing drink, evidence suggests that this is actually merely the reversal of the fatiguing effects of acute caffeine withdrawal," wrote the scientists, led by Peter Rogers of Bristol's department of experimental psychology.

The team asked 379 adults -- half of them non/low caffeine consumers and the other half medium/high caffeine consumers -- to give up caffeine for 16 hours, and then gave them either caffeine or a dummy pill known as a placebo.

Participants rated their levels of anxiety, alertness and headache. The medium/high caffeine consumers who got the placebo reported a decrease in alertness and increased headache, neither of which were reported by those who received caffeine.

But measurements showed that their post-caffeine levels of alertness were actually no higher than the non/low consumers who received a placebo, suggesting caffeine only brings coffee drinkers back up to "normal."

The researchers also found that people who have a genetic predisposition to anxiety do not tend to avoid coffee.

In fact, people in the study with a gene variant associated with anxiety tended to consume slightly larger amounts of coffee than those without it, Rogers wrote in a study in the Neuropsychopharmacology journal, published by Nature.

This suggests that a mild increase in anxiety "may be a part of the pleasant buzz caused by caffeine," he said.

(Reporting by Kate Kelland; editing by Peter Graff)

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Comments (21)
CindyBP wrote:
Oh, please.

Jun 02, 2010 1:16pm EDT  --  Report as abuse
DramaDude wrote:
They’ve got my number.

Jun 02, 2010 2:01pm EDT  --  Report as abuse
AnnieP1 wrote:
More evidence that the UK can cut their budget by starting with stupid scientific research.

Jun 02, 2010 3:17pm EDT  --  Report as abuse
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