Picture credits: https://www.pinterest.com/pin/52213676918686749/ "Coffee & Moss Sticker" designed by DANYEL POINDEXTER
Brewing a hot cup of coffee in the morning has evolved into muscle memory for many, whether it be because of a late-night spent finishing off some work, or simply because we trust the familiar bittersweet taste to power us throughout the day.
Caffeine is a natural component of plants such as guarana, cacao trees, tea leaves and Coffea, a genus of flowering plants grown in around 80 countries where coffee beans are found. The reason why caffeine can be traced back to plants is because they produce this chemical to improve their survival: caffeine deters pests by paralyzing and killing them, and further prevents seeds from germinating near the plants, therefore reducing competition for resources. However, we regularly consume this exact same chemical because it elicits a different effect on humans, elevating our alertness and boosting our energy. And this, of course, can be answered using science.
Picture credits: https://botanyphoto.botanicalgarden.ubc.ca/2015/09/coffea-arabica/
As the day goes by, energy is produced from breaking down a compound called ATP, releasing a chemical called adenosine which accumulates in your body throughout the day. When adenosine binds to its specific receptors in the brain, it causes the feeling of sleepiness as neural activity is slowed down, explaining why we get more tired and drowsy towards the end of the day. Caffeine of the methylxanthine class has the formula of C8H10N4O2 (in subscript), and its shape closely resembles that of adenosine. As a result, it can bind to the adenosine receptors instead, acting as what we call an adenosine receptor antagonist. This essentially “kicks out” adenosine as it prevents adenosine from binding to its receptors, which inhibits the decrease in neural activity, or in other words, stops the feeling of sleepiness.
Caffeine also stimulates the production of adrenaline. It affects the hypothalamic-pituitary-adrenal (HPA) axis, causing the hypothalamus in the brain to trigger the release of ACTH from the pituitary gland, which in turn triggers the release of adrenaline from the adrenal glands, a sort of cascade effect. This hormone is commonly known for increasing alertness in preparation for a “fight-or-flight” response, as it increases heart rate and blood flow to muscles to achieve this.
You might have heard of dopamine, the infamous chemical responsible for feelings of pleasure. As it turns out, caffeine additionally prevents the reabsorption of dopamine in the brain while adenosine normally inhibits the release of dopamine, therefore causing this exact feeling of pleasure which can explain why some people have a caffeine addiction.
For all these reasons, caffeine can be classified as a stimulant, which is defined as a drug that speeds up the Central Nervous System (CNS for short), increasing neural activity.
It is no secret that many people consume caffeine as a habit, but as their caffeine consumption increases more and more, it might actually result in what we commonly understand as “building up tolerance”. This happens because the brain responds to increased caffeine consumption with the formation of more adenosine receptors. With the extra presence of adenosine receptors, logically, more caffeine would be needed to bind to them in order to produce that same level of energy and alertness. Therefore, a person might experience withdrawal symptoms, characterised by headaches, tiredness and sleepiness, if they suddenly do not drink their normal cup of coffee one day.
On the contrary, the over-consumption of caffeine can lead to caffeine intoxication, which can produce quite nasty effects such as nervousness, excitement, increased urination, insomnia, and in the most extreme cases, hallucinations can occur. Scientists have agreed that the lethal amount of caffeine intake is 150mg/kg (of your weight), which equates to a very, very enormous and mind-boggling number of cups of coffee. (please don’t try this. It’s dangerous. Very, very dangerous.)
Staying true to my blog name, I am, without a doubt, a big coffee-lover. But as with most things, caffeine should definitely be consumed in moderation (although exam season is approaching, so that calls for a cup of coffee… or make it two). Weirdly enough, its bittersweet taste or the energy it gives me aren’t the biggest factors that make coffee my best friend and possibly my only personality; rather, I love the art of it more than anything. I love the ambience of coffee shops and doing work with a steamy cup of coffee in hand. I love the multitude of different styles in which coffee is made, and the effort and artistry behind it. Ultimately, I love the joy and pure excitement it brings when we realise that coffee shops have officially launched their signature festive drinks– the Christmas-themed coffees never fail to amaze me, they are the most delicious drinks ever!
Here are some fun facts about caffeine!
· Caffeine was first isolated in 1819 by the German chemist Freidrich Ferdinand Runge.
· Studies have shown that caffeine can prevent diabetes, and caffeine has been linked to preventing Parkinson’s and Alzheimer’s disease.
· Pure caffeine is an extremely bitter white crystalline powder.
· Caffeine is the most widely-used drug in the world.
· Caffeine takes 30-60 minutes to reach its peak level in the blood, according to the American Academy of Sleep Medicine.
Sources:
Videos:
"How does caffeine keep us awake?" - Hanan Qasim - TED-Ed
"Your Brain On Coffee" - AsapSCIENCE
"The Science of Caffeine: The World's Most Popular Drug" - Reactions
Articles/readings:
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