Caffeine – our favourite legal drug
No wonder millions of people around the world drink it: caffeine-containing beverages, such as coffee and tea, are the most popular psychoactive drug. But should we be concerned about the ever-increasing array of drinks that contain caffeine?
In this fact sheet, Leanne Cooper examines caffeine, its sources, and its effect on the body – providing you with all the necessary information to make the final decision.
Our Nutritionist, Leanne Cooper, can also provide you with answers to your questions in the Huggies Help Panel .
Caffeine is found in the leaves and beans of the coffee tree, in tea leaves, guarana berries, and in small amounts in cocoa and the kola nut. If you enjoy a cup of Rooibus, you will be pleased to learn that this tea comes from a different plant and contains no caffeine. Caffeine also turns up as an ingredient in cold medications, appetite suppressants and pain relievers, and can be helpful against some headaches and of course to combat drowsiness.
Surprisingly, it’s the leaves of the tea plant that contain the most caffeine, around 5% compared to 1-2% for coffee beans. Plants cleverly use caffeine for survival as it repels many insects.
As most of us know, caffeine stimulates our central nervous system (CNS), helping to keep us alert (that get-up-and-go feeling) and overcome listlessness
What’s in a cuppa?
Depending on what you read, the amount of caffeine in food will vary. A 150ml cup of tea varies from 30-100mg of caffeine. A determining factor is how the tea is made. Adding milk, sugar, using loose leaves or teabags (strong loose-leaf tea provides the most caffeine) all create a different result.
Coffee beans come in two flavours: Robusta, which has more caffeine, and Arabica. A 150ml cup of drip-percolated coffee typically has a caffeine content of 100-150mg; instant coffee has 60-100mg per 150ml, depending on the brand. An espresso comes in at around 90mg per 150ml. This is good news for those mums who sneak in an espresso after dropping off the kids at school.
What about chocolate?
A 200g block of chocolate contains the equivalent of about 550mg of combined methylxathines (caffeine-like compounds and other stimulants). A 30g bar has between 20-60mg caffeine. This may be something to note if you have a child who is overly active and enjoys the odd chocolate bar.
Given our teenagers are the ones who consume the greatest quantity of soft drinks, caffeine intake is something to keep an eye on.
A 375ml cola drink contains around 40mg of caffeine while a 250ml energy drink contains around 80-100mg caffeine – about the same as a shot of espresso. No wonder we have trouble keeping up with our teenagers!
The rate at which our bodies metabolise caffeine depends on our liver and its ability to deal with such drugs. While it’s been found that women can clear drugs such as caffeine from their liver faster than men, this is influenced by hormone levels and medications. It takes longer for women to clear such drugs when they are pregnant or on the oral contraceptive pill.
Caffeine is rapidly absorbed in less than an hour. After this, it has a half-life (the time it takes for the total amount taken in to be reduced or cleared to half) of 3.5 to 6 hours.
Note: Caffeine content is highly unpredictable in coffee and tea, especially in tea. Preparation is a huge factor and colour is a very poor indicator of caffeine content. Teas such as the green Japanese Gyokuro contain far more caffeine than much darker teas like Lapsang Souchong, which have very little. Even approximate caffeine contents assigned to teas are generally very inaccurate.
For more information see Pregnancy and Diet.