Coffee is a wonderful drink that works magic on our bodies. When it first arrived in Europe, its popularity spread like wildfire, and Europeans rapidly switched from being heavy alcohol abusers to being caffeine abusers. While any kind of substance abuse is not ideal, a society jazzed up on stimulating caffeine instead of depressing alcohol is likely to fare much better in terms of realizing its goals and creating new advancements. Was caffeine a spark for the Enlightenment in Europe? It could have been.
From time to time, I hear someone say that coffee is a placebo. That the only reason you get an influx of energy after drinking coffee is because you expect to.
That is not true; caffeine affects your body in several clear and observable ways. Caffeine is a stimulant of the central nervous system. Most often, when people dismiss the effects of caffeine as a placebo, it’s because they have had personal experiences in which it didn’t work. These people often swear they can drink as much coffee as they want, yet feel as sleepy as before, or even sleepier. There are two possible reasons for this:
- First, caffeine creates tolerance. That is, with prolonged caffeine use, your body adjusts and you need more caffeine to feel the same effect.
- Second, too much caffeine can create the opposite of the intended effect. You’ve likely noticed that on some days, no amount of coffee can wake you – it just gets worse with every cup.
How does caffeine work?
I promise, there won’t be a lot of compound names in this article and you won’t have to understand chemical reactions. One thing that you should understand, however, is that the cells in our body communicate with each other using small signal molecules.
One of these molecules is adenosine. The reason you need to be familiar with adenosine is because it’s relatively similar to caffeine (see the picture below).
Adenosine is abundant in our body and serves quite a few functions. It makes up a part of our DNA (the letter “A” in our genetic code stands for adenine) and plays an important role in our energy metabolism as part of the ATP molecule. The latter you may remember from school as the energy currency inside our body.
Among its many functions, adenosine is also a signal molecule used by your brain cells. Adenosine attaches to receptors in brain cell membranes and carries signals to indicate a lack of energy or a prolonged “awake” state. Thus, in response to adenosine buildup, our body begins to feel drowsy. At this point, we are likely to take either a nap or grab another sip of coffee.
Coffee, just like tea, dark chocolate and Coke (especially Diet Coke), contains caffeine. As I mentioned earlier, caffeine molecules behave in a way that is strikingly similar to adenosine.
What’s most intriguing is that adenosine and caffeine are similar, but not identical. The caffeine molecule can bind to adenosine receptors. However, unlike adenosine, caffeine does not “turn on” these receptors, so to speak. They simply sit there, doing nothing and taking up space, which is important for the effect caffeine has on your body.
The important part is that caffeine molecules bind to these receptors much more easily (with higher affinity) than adenosine molecules. This allows caffeine molecules to bind to most of the receptors, leaving adenosine molecules with very few places to bind. Therefore, your body cannot determine the actual level of adenosine or recognize that it is low on energy and needs rest. Thus, instead of feeling drowsy, you feel energized. It is like adenosine would like to phone the body and tell that he is tired, yet all the phone booths are occupied by caffeine.
Is too much caffeine bad for you?
Isn’t it bad that coffee does not actually give you energy but is simply tricking your body? A common presumption is that adenosine keeps building up in your system and once the caffeine leaves your body the adenosine then binds to these receptors in huge amounts. What would happen then? Would you face a meltdown?
Obviously the answer is no. Coffee consumption does not directly impact the buildup and breakdown of adenosine. Adenosine actually builds up and breaks down rapidly, and caffeine only blocks its access to receptors. So it doesn’t continue to build up excessively just because you had coffee. Problems can arise, however, if you chronically get too little sleep and use coffee to compensate.
Remember, coffee does not give you energy; it only tricks your body into thinking you have more energy than you do. You still need a good night’s sleep to fully recharge. At the same time, less than 400 milligrams of caffeine per day is considered to be safe. This amount is equal to four mugs of coffee a day. So the next time you feel down, have a cup of coffee and let the caffeine do its magic – just don’t overdo it.