Caffeine is the world’s most popular drug and can be found in a wide variety of products including chocolate, coffee, cola and tea. Caffeine is found naturally in many plants, such as coffee beans and cocoa nuts but why do some manufacturers artificially add caffeine to their products and why are some people unable to start their day without it? These are some of the questions I will try to answer in this article.


Why do we feel tired?
During our daily activities our bodies continuously create a compound called adenosine. When enough of this compound has piled up inside us it binds itself to cells, receptors, which are located throughout our body, primarily in the brain. You can think of these receptors as keyholes, with the adenosine molecules being their specific keys. Most other compounds will not fit in those keyholes, in other words: they can not bind to the receptors. When the adenosine molecules bind to the receptors in the brain, signal substances are released that give the body the idea that it is sleepy.

What does the caffeine do?
   
Caffeine, or 1,3,7-trimethylxanthine, which is its proper chemical name, has a molecular structure that looks very much like adenosine’s molecular structure. Caffeine molecules are actually so much alike adenosine molecules that they can fit into those keyholes we discussed earlier. This fills those keyholes up so that the adenosine can not get there to perform its duty and while the caffeine is sufficiently similar to adenosine to bind to the receptors, it is not similar enough to start the reaction that promotes drowsiness. Thus, with a proper dose of caffeine in our brain, we continue to feel as brisk and alert as ever even when our adenosine levels are high. Actually, when the caffeine binds to the receptors, the cells speed up instead of slowing down.
With all the ruckus going on in the brain due to the increased cell activity, the pituitary gland thinks that the body must be in some sort of urgent situation and orders the production of adrenaline. Adrenaline is an "emergency" hormone that, for example, increases the pulse and the blood flow to the muscles. This further suppresses any thought of going to bed. Another effect of the binding of adenosine to the receptors is that the blood vessels in the brain opens up, the reason for this is presumably to give the brain a little more oxygen during sleep. Neither this is happening once the caffeine has stuck itself in the receptors and this is the reason why some headache medicines contain caffeine, the increased blood flow caused by the adenosine can cause vascular headaches, this, of course, does not happen when the caffeine is present.
Caffeine also makes you "feel good" in the same way amphetamine, heroine and cocaine do; by manipulating the dopamine levels in the brain. Dopamine stimulates the "pleasure centre" in the brain and even if the effect of caffeine is way below that of heroine and cocaine it contributes to making the intake of caffeine a rather enjoyable experience.

The backside of all the wonderful peppiness
    This may so far sound all nice and well, feeling alert and free of headaches and at the same time getting your brain’s "pleasure centre" stimulated but there are cons to caffeine consumption as well. First of all we have the addiction part. Caffeine is actually an addictive drug, not only because of the dopamine but also due to other reasons. When the caffeine begins to wear off the adrenaline production stops and the adenosine molecules begin to find their way into their keyholes again. This makes you feel fatigued and not quite as brisk or alert anymore. When the caffeine levels drop you may also experience a headache due to the dilation of the blood vessels. How do you solve all that? Easy, you grab yourself another cup of coffee.
    Another thing that adds to the addictive effect is the fact that adenosine’s binding to the receptors is essential for your deep sleep and that caffeine remains in the body for quite some time. This means that a cup of coffee or a couple of colas in the middle of the day will have a serious impact on the refreshing benefits of your sleep during the night. This in turn means that you will be rather tired the following morning and how are you going to solve that problem? Again the ideal solution is another cup of coffee! The circle is completed. Of course, if you are used to drinking a cup of coffee every morning, habit will also play a part in the drama.
    Secondly it is not really healthy to run around with high adrenaline levels all the time. That could be compared to the American government trying to run the country while constantly having defcon five. It makes you on edge and short-tempered.

    Many people do not realise that they are addicted to caffeine and it is presumably this subtle addictive effect that make manufacturers put it in their products. The Coca Cola Company claims that the caffeine is added purely as a taste enhancer but tests have shown that very few people actually can taste the difference between cola with and without caffeine. The Coca Cola Company’s claims remain however, and who am I to say that they are lying? It is up to each and every one of us to make our own judgement of them and the other manufacturers.

    If you have any questions or if you want me to explain anything further feel free to email me at mattias.vagberg@telia.com or the address given below, and don’t think that you are bothering me by doing so because you are not, I enjoy getting emails so fire away. In the meantime I am going to fetch myself a coke, I think I am beginning to get a headache.


© 2003 Freeway
Writers: Mattias Vågberg (nv04-41@park.se).
HTML by: Tomas Sjölund (te04-43@park.se).