Caffeine is a psychoactive central nervous system stimulant. It is found naturally in a good handful of plants that have propagated significantly thanks to human influence.
It’s a very simple thing to wander down to a café and have a cup of tea or coffee, or to get a guarana-based energy drink or cola from a vending machine, but how exactly does the compound affect your biology? How can you reap the benefits whilst minimising or even neutralising some of the less-than-beneficial side effects?
To reiterate, caffeine is a central nervous system stimulant. What does that mean exactly? To put it simply, caffeine, when consumed, causes the functions of the central nervous system (i.e. cognition, mental acuity etc) to operate to a higher degree. It does this by blocking the adenosine receptors in the brain, stimulating an adrenal response, and so making your brain work a bit more efficiently.
Adenosine is a compound produced naturally in the brain steadily over time whilst awake. As adenosine binds with certain receptors in the brain, the organism begins to feel more and more drowsy. Whilst sleeping, the amount of adenosine in the brain steadily decreases. Pretty simple system, right?
Caffeine gets in the middle of this process by binding with these receptors, due to its similar structure, and blocking adenosine from doing so. This essentially causes the brain to go “hang on, I’m not getting any adenosine. Better kick this bad boy into gear to figure out what’s going on”, releasing adrenaline (the “fight or flight” hormone). The adrenaline then constricts blood vessels, causing blood to flow more quickly to the brain and skeletal muscles, increasing the efficiency of those tissues and taxing the body’s resources.
The increased blood flow requires extra water to deliver more oxygen around the body, so you’re going to want to have extra water with your cup of coffee or energy drink. A study found that having a cup of coffee each week reduced iron absorption by 1%. So, for those who choose to enjoy coffee on a regular basis, increasing the vitamin C in your diet (especially between consuming caffeine and iron-rich foods) is a really great way to keep iron absorption on track; especially if you have a form of iron deficiency or stunted iron absorption.
Caffeine consumption has proliferated massively in many ways. There are now caffeinated soaps, chewing gum, and even spray-on caffeine. It’s just very interesting to see how some drugs like caffeine have been consumed in safe proportions in society completely unregulated.