Caffeine produces greater effect on men than women

London, Dec 23 (IANS) Caffeine produces a greater effect on men than women. The effect begins to make itself felt just 10 minutes after it is drunk.

And contrary to previous thinking, decaffeinated coffee also produces an increased state of alertness.

'Numerous studies have demonstrated the stimulant effects of caffeine, but none of these have looked at their effects in terms of the consumer's gender,' said Ana Adan, co-author of a new study on the subject and a researcher in the Psychiatry and Clinical Psychobiology Department of University of Barcelona (UB).

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Research into the effects of caffeine tends to be carried out using preparations in which the caffeine level is much higher than normal intake.

The novelty of this study lies in 'the difference seen in the effects on men and women, based on the quantities of caffeine people take in 99 percent of cases (espresso coffee and decaffeinated espresso coffee, containing 100 mg and 5 mg of caffeine, respectively),' said Adan.

Scientists used a sample of 668 university students (238 male and 450 female) with an average age of 22 years, said a Plataforma SINC release.

Measurements were taken before and after the caffeine was ingested (10, 20 and 30 minutes) and were carried out at mid-day (11 a.m. to 1 p.m.) and in the afternoon (4 p.m. to 6 p.m.), to act as a control in case of possible differences caused by the time.

'Although both the men and women saw an improvement in their activity levels with the coffee, which increased in later measurements, we observed a greater impact among the males,' the researcher said.

When the decaffeinated version was introduced into the study, the authors also found a small subjective improvement in the participants' state of alertness, which did not rise so strikingly in the later measurements.

Caffeine has an almost immediate effect. Previous studies had shown that alertness starts to increase 30-45 minutes after consumption, but the new study shows that the effects begin after as little as 10 minutes.

According to the researcher, '45 minutes is the time needed for maximum caffeine concentration to be reached in the blood, but levels reach half this concentration after just a few minutes.'