Pay Attention to Coffee and Tea

Caffeine and theanine shown to increase performance on sustained attention tasks

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Many people cannot stay productive at work without their favorite beverage. It turns out that there may be more to this than a coffee habit.

For thousands of years people have been using coffee and tea to stave off drowsiness.

Recent clinical trials show in addition to keeping people awake, alkaloids found in these beverages also increase a person’s ability to pay attention to monotonous tasks without distraction.

"Drink some coffee or tea - it might increase your attention span."

John J. Foxe, PhD, a professor and researcher from Yeshiva University’s Albert Einstein School of Medicine, was the lead author for this study. This study was conducted at the Nathan S. Kline Institute of Psychiatric Research in Orangeburg, NY.

Twenty-seven volunteers were recruited through the Institute’s volunteer pool. Twenty-one of those volunteers completed the study, which was enough to make statistical conclusions.

The compounds that Foxe and his team were examining were two compounds found in coffee and tea. Most people have heard of caffeine, the alkaloid that gives coffee and tea their characteristic kick. Theanine, an amino acid similar to glutamate, is another compound found in both beverages that can provide a stimulating effect.

The study participants took part in the trial across five days. The first day consisted of a questionnaire and a training session to familiarize the participants with the Sustained Attention to Response Task (SART), which was the primary assessment tool used for this study.

On the subsequent four days, the participants were given either 50mg of pure caffeine or 100mg of theanine dissolved in water, both of them together, or a placebo (in this case plain water). The order each participant received one of these four possibilities in was randomly determined, and the researchers as well as the participants were unaware of which treatment was given on which day.

The SART is a simple cognitive test lasting 12 minutes, during which the subject is shown numbers (1-9) in a random order. When each number comes on the screen, the subject is instructed to click the mouse.

The only exception is that they are not supposed to click the mouse for the number 3. Reaction time as well as accuracy is measured. The SART test was administered thirteen times, with two minute breaks between each test, and a sustained 11 minute break in the middle of the test regime.

Each participant’s brain waves were also measured using electroencephalography while testing was being conducted.

There are basically two ways to measure error on a test like the SART. An error of omission occurs when participants fail to click the mouse for the numbers 1-2 or 4-9, and an error of commission occurs when they click the mouse for a number 3 when they aren’t supposed to.

Taking theanine alone decreased participants’ errors of omission by 36 percent and errors of commission by 23 percent in relation to the placebo results. Response time was not affected by theanine, nor was brain wave activity.

Caffeine reduced errors of omission by 50 percent and errors of commission by 30 percent when compared to the placebo results. Caffeine also decreased reaction time by 3 percent compared to the placebo.

For the first half of the test regime, after caffeine ingestion, alpha brain waves decreased by 12 percent compared with the placebo. Alpha brain waves are thought to be present when the brain is “idling” and are associated with attention. Foxe and his team guess that this allows more of the brain to process the information on the task at hand.

The results of the combination of caffeine and theanine were no different than the results for caffeine alone. Foxe and his team suppose that this may be evidence of a “ceiling” effect, which means the cognitive benefits eventually stop adding up at a certain point.

For future research, Foxe and his team feel that lower doses of caffeine and theanine would be able to better assess if there is any effects from the combination of the two alkaloids.

This clinical study was published in June issue of the journal Neuropharmacology. Funding for this study was provided by a grant from Unilever. There were no reported conflicts of interest.

Reviewed by: 
Review Date: 
June 18, 2012
Last Updated:
October 26, 2012