Health Tip
Tea or Coffee?
Question: I read recently that tea contains more caffeine than coffee. I have often heard this quoted before, but my own experience is that this can't be true. If I drink a good strong cup of cappuccino, the jolt of the caffeine makes me feel like a nervous wreck for several hours afterwards. However, I often drink a cup of tea before bedtime, and subsequently get a very sound night's sleep. Do tea and coffee have different effects or does the caffeine level depend on the type of tea or coffee? Are there different types of caffeine?
Answer: With respect to the first part of the question, tea does indeed contain more caffeine than coffee, but only by dry weight, not by its final concentration in the beverage. Because much more ground coffee than tea leaves are used to brew the respective drink, coffee typically ends up with a considerably higher caffeine concentration.
In answer to the second part of the question, the caffeine content of different species of coffee and tea plant can vary widely, as can the presence of other stimulant alkaloids such as theophylline and theobromine. But the physiological effect of equivalent amounts of caffeine is the same regardless of its source, because--in answer to the third question--there is only one type of caffeine, namely 1,3,7-trimethylxanthine.
As drunk in Britain , a strong cup of tea contains about the same amount of caffeine as a weak cup of instant coffee. Tea also contains small amounts of theobromine and theophylline which, like caffeine, are methylxanthines. But they have relatively weak stimulant effects.
If the tea is brewed for only a short time it will contain little caffeine and therefore may not be very stimulating. However, in terms of the likely effect on you, your state of caffeine abstinence prior to caffeine consumption is probably more important. If you are a regular caffeine consumer (three or more cups of tea or coffee a day), you will feel a noticeable benefit with the first cup of tea or coffee in the morning, mainly caused by removing the fatiguing effects of overnight caffeine withdrawal--after between 8 and 10 hours of caffeine deprivation, caffeine levels in the body have typically fallen by 80 per cent.
In contrast, tea or coffee consumed before bedtime has a less obvious impact, because having consumed several cups during the day--usually at increasing intervals--this last drink will tend only to maintain the body's levels of caffeine.
|