Caffeine is the most widely consumed natural stimulant in the world. As a central nervous system stimulant, caffeine speeds up how quickly information travels from the brain to the body and back. It also increases the circulation of certain hormones such as adrenalin and cortisol in the body. Caffeine is a naturally occurring substance and commonly found in leaves, seeds, fruits and nuts of around 60 different plant species. While caffeine is usually associated with coffee, it can also be found in tea, energy drinks, sodas, chocolate, medications and various supplements.
When we consume caffeine, it is absorbed within 45 minutes and then enters our blood and various tissues. The amount of caffeine in our body reaches its peak concentration within 15-120 minutes. This process of absorption doesn’t differ much between individuals. However, how caffeine is metabolised differs from person to person, as its metabolism can be influenced by a variety of factors. These factors include smoking, drinking alcohol, liver-related diseases, use of medications, dietary intake as well as genetics.
The effects of caffeine intake can be both positive and negative. While the effect is often correlated to the quantity of caffeine that you consume, it can also be affected by your genetic profile. A set of liver enzymes are responsible for around 90% of caffeine metabolism. CYP1A2 is the gene that codes for the enzyme responsible for caffeine metabolism. The activity of CYP1A2 can vary quite significantly and can therefore have a profound impact on caffeine metabolism. Those with increased CYP1A2 activity are likely to experience the effects of caffeine a lot faster, as caffeine is more likely to reach its peak concentration in the body faster.
Caffeine has an average half-life of around 4 hours, this means it typically takes around 4 hours for half of the caffeine you have consumed to leave your system. For those with increased CYP1A2 activity, this half-life is likely to be shorter. Therefore, not only do fast caffeine metabolisers experience the potential effects of caffeine faster, but caffeine will also leave their system much faster. If someone with a faster caffeine metabolism enjoys the effects that caffeine has on their body, they are more likely to consume larger quantities of it more frequently to experience this effect.
It is important to remember that regardless of your caffeine metabolism, you will potentially experience the effects of caffeine. The onset and duration of that effect are what will likely differ from person to person. Like with almost any other stimulant, your body will eventually adjust to the intake of caffeine. For example, the more regularly you have it, the less likely you are to experience a significant effect from it. This also often leads to an increase in caffeine intake. Individuals will start to consume more caffeine to try and achieve the effect that they used to experience when they initially started consuming it.
As mentioned above, the effects of caffeine can be both positive and negative, so what exactly are the potential effects?