Caffeine can cause insomnia

Sleepless on coffee and tea

Five o'clock, late afternoon - or early evening. "No, please don't," the friend puts her hand protectively over the coffee cup. "Else I can not sleep."

Even after enjoying black tea in the early evening, many people sit upright in bed. Others, on the other hand, sleep well a few hours after consuming coffee and black tea. Others, on the other hand, cannot sleep at all on short black tea, but excellent on long brewed tea. How do such different reactions come about when coffee and black tea contain the same active ingredient - caffeine?

"Caffeine is the most potent, but not the only ingredient that affects the central nervous system," says Veronika Somoza, Head of the Institute for Nutritional Physiology and Physiological Chemistry at the University of Vienna - for example the theophylline that is predominant in black tea or that in coffee contained pyrogallol. "The caffeine content of coffee and tea are also different, so you can't compare the two across the board," says the nutrition expert.

Theophylline works like caffeine

A short tea is said to make you lively, a long tea makes you tired. "The theophylline, which is mainly contained in tea, has a similar effect to caffeine," says Somoza. During the extraction of coffee or tea, these compounds pass into the water, and the extraction is more or less effective depending on the length of the brewing period.

Most of the theophylline or caffeine is extracted in the first few minutes, but the longer you steep the tea or coffee, the higher the concentration. "However, you have to look at the quantitative proportions," adds Veronika Somoza and assumes the following scenario: If you let 150 milliliters of black tea steep for one minute, this results in approx. 20 milligrams of caffeine. After three minutes, it contains around 35 milligrams of caffeine.

Caffeine content between 60 and 120 milligrams

Can these 15 milligrams make it harder for you to fall asleep in the evening? "I think you should drink a little more of it," says Somoza with conviction and uses the same example with coffee: The brewing process in the filter coffee machine takes between four and eight minutes. "That makes a difference. Depending on which coffee beans were used for roasting and how long the brewing process took, the caffeine content is between 60 and 120 milligrams."

Whether a cup of tea has a similar or even stronger stimulating effect than a cup of coffee does not only depend on the caffeine content: "The amount of caffeine in a cup of coffee can be between three and six times as high as that in one Cup of tea, however, other ingredients are also effective here. In addition, regular intake of caffeine has a habituation effect, so that the stimulating effect of a cup of coffee is much less noticeable in people who drink coffee regularly, and also the different effects of one Cup of coffee and tea should hardly be noticeable ".

Different preparation method, different effect?

So it's just imagination - or heightened sensitivity. Does the method of preparation - espresso, filter coffee, "Turkish coffee" - make the difference in the effect? "You can't lump the effect with one brush or just pinpoint it to the caffeine," says Somoza, "because the different types of preparation cause shifts in the overall profile of the ingredients." Even with tea, one cannot say: if drawn for five minutes it looks like this, if drawn for eight minutes it looks different, because the profile of ingredients differs from tea to tea, plus the short or long steeping.

Decaffeinated coffee

When asked about the digestibility of coffee - the great drink of poets and thinkers - and caffeine as a psychoactive drug from the group of stimulants, Somoza disaffected: "Caffeine can stimulate the production of stomach acid. However, moderate coffee consumption with dark roasted, decaffeinated coffee is more digestible" , and adds: "Incidentally, decaffeinated coffee still contains around three milligrams of caffeine per cup."

So the matter is as complex as it seems: the effects of tea and coffee are likely to depend on the type of tea and coffee in question, how it is prepared, how it is steeped and how the individual feels. (Eva Tinsobin, derStandard.at, December 28, 2011)