It is estimated that more than two billion cups of coffee worldwide are drank everyday. Add the delightfully restorative drink ‘tea’ into the equation and no other mood-altering stimulant is consumed on such a potentially global jitter-inducing scale.
So, what exactly is caffeine?
Firstly, caffeine comes from an organic family of nitrogenous compounds called xanthine alkaloids that, when consumed, give rise to marked physiological – and psychoactive – effects on the human body. Other sources known to contain this powerful compound include the Gurana berry, Cocao bean, Kola nut, Yaupon Holly tree, and South American Yerba mate, amongst many others (so far, up to 60 plants are known to contain the compound caffeine).
But for the purposes of this post, I trust that you will forgive me if we stick to coffee.
In 1820, caffeine was first isolated from coffee by the German chemist Friedlieb Ferdinand Runge, apparently at the behest of Johan Wolfgang von Goethe. The following year, the French chemist Pierre Joseph Pelletier, coined the word ‘cafeine’ after the French derivation for the word coffee; café. However, it was not until the end of the 19th century that its complete chemical structure was discovered by Hermann Ermil Fischer, who was the first person to achieve its total synthesis. Fishcher was later awarded the Nobel Prize in 1902 for his work in this field of organic chemistry.
Caffeine, or to use its laboratory name – 1,3,7-trimethylxanthine – manifests itself in its purist from as a white crystalline solid. Yet to the human brain, it is one of the most effective ‘cuckoo’ compounds in the chemical world.
Throughout the day, the neurotransmitter adenosine is naturally created in the brain and builds up to a level that eventually helps to bring about the onset of that deep, regenerative state we know as sleep. It binds to the receptors resulting in a feeling of drowsiness by slowing down nerve cell activity whilst the blood cells dilate to allow more oxygen to the brain.
Now, as far as your average nerve cell is concerned, caffeine, with its chemical structure – C8H10N4O2 – looks suspiciously like adenosine – C10H13N5O4 – thereby allowing this chemical ‘master of disguise’ to bind to the adenosine receptors. But the psychoactive result is the exact opposite. Instead of inducing a feeling of drowsiness, the chemical composition of caffeine encourages the nerve impulses to speed up.
This build up of chemical mimicry prevents the real adenosine from binding to its own receptors. Consequently, the brain is kick-started into a state of arousal and becomes more alert. The stimulating effects of caffeine on the central nervous system also dramatically increases the amount of the ‘happy’ neurotransmitter dopamine to be produced. These heightened levels are coupled with feelings of well-being and improved mood. It is in fact the psychoactive effect of dopamine that makes caffeine so addictive.
Now things start to get really interesting.
As the brain experiences a speeding up of nerve cell activity caused by the neuro-pathways firing on all cylinders, the body goes into ‘fight or flight’ mode. It is at this juncture that the pituitary gland steps into the proceedings, and sensing an emergency, sends a signal to the adrenal glands to produce more of the hormone epinephrine, also known as adrenaline.
We all know what happens next.
With the body now in a state of heightened alert, the all-too-familiar symptoms of increased heart rate; raised blood pressure; sweaty palms; a ‘spike’ in levels of blood sugar produced by the liver to provide extra energy; dilated pupils; suppressed appetite; and a tensing of the muscles; are just some of the side-effects of this biological ‘code red’. Once the perceived ’emergency’ is over, the body’s adrenaline and dopamine levels start to return back to normal, coupled with a slowing of nerve cell activity as the adenosine begins to bind to the receptors once again. It takes approximately ten hours for caffeine to fully leave the system.
Like anything consumed in excess, too much caffeine can prove fatal. Just 10g is considered a lethal dose. Fortunately, an average espresso contains a mere 100-150mg so seriously herculean quantities of the stuff would have to be consumed in a single sitting to bring on death.
This cannot be said of spiders…
In the final analysis, we all have to make our own personal judgement about the pros and cons of caffeine consumption, once in full possession of the facts.
But before you reach for the decaf (which still contains caffeine – just a reduced amount), stop and spare a moment to consider this mysterious but potent ‘cuckoo’ of the chemical world, and its powerful effects.
For good or for bad, it is without equivocation that caffeine on the brain changes the body’s chemistry.
In more ways than one.