we’re all familiar with the effects of caffeine but what exactly is it? why do plants produce it? what does it do to our bodies and is it good for us?

over 100,000 metric tons of caffeine are consumed around the world every year. that’s equivalent to the weight of 14 eiffel towers.

hanan qasim | TED-Ed

caffeine is produced naturally in more than 60 different plants but more surprisingly each develops different biochemical mechanisms and pathways to create caffeine — a phenomenon known as convergent evolution.

it serves as a plant’s defense against insects, acting as a natural pesticide to deter bugs from attacking and eating them. it achieves this in part with a bitter taste, but caffeine is also toxic to some herbivore insects. we often burn coffee grounds to get rid of bugs in our garden.

caffeine also has a surprising impact on bees in that it can improve their memory by increasing the associations they develop between the smell of flowers and its nectar and giving those plants a competitive advantage in the world of pollination. natures aphrodisiac, if you will.

to most, caffeine and coffee go hand in hand and it’s indeed named for coffee. but caffeine isn’t limited to coffee. it’s also found in tea, chocolate, kola nuts, guarana seeds, and even the flowers of citrus plants and was originally consumed way back in 3,000 b.c. as tea. incidentally, gram-for-gram tea has more caffeine than coffee!

coffee only started to become popular in the 15th century, starting in yemen where the legend of “kaldi” the goat herder originated. according to the story, kaldi, happened upon his herd of goats chewing on coffee cherries and saw first hand the plants stimulating effects and so decided to for himself.

within academia, the discovery of caffeine is a little unclear with two known discoveries made, first by german chemist friedlieb ferdinand runge who extracted a pure caffeine isolate called kaffebase in 1819. and then in 1821 french chemist pierre jean robiquet discovered caffeine independently in his research and is widely credited with its discovery.

within the body, caffeine acts as a stimulant by blocking adenosine which our bodies use to induce sleep. it does this by derailing the process of adenosine molecules docking with the receptors in our brain. how? well, caffeine’s molecular structure is close enough to adenosine’s that they fit into our brains adenosine receptors without actually activating them!

in a non-caffeinated body where adenosine (produced as a result of the breakdown of the high-energy molecule called atp) can dock with neurons causing them to fire more sluggishly and slow the release of important brain-signaling molecules. the result? we get sleepy.

put it all together and you see that, adenosine inhibits your neurons. caffeine inhibits the inhibitor, so you don’t get sleepy and feel more awake or stimulated.

caffeine also has a positive effect on our mood by increasing our receptors’ ability to pickup dopamine (the pleasure-giving molecule). just like caffeine makes it harder for adenosine to dock with a receptor, conversely, this makes it easier for dopamine to fit causing a release of pleasure and uplift in mood.

this positive impact has lead to increased evidence that caffeine consumption has long-term benefits in reducing the risks of some aspects of diseases like alzheimer’s and parkinson’s as well as having preventative effects on some types of cancer.

did you know that between 1984 and 2004, caffeine was actually on the olympic committee’s list of banned substances — with athletes having to regulate their caffeine intake to concentration levels below 12micrograms per milliliter to compete! by 2004 it was removed from the list as more research into caffeine metabolization found that people’s body types metabolize caffeine differently and it was ultimately an unfair thing to police.

from a training perspective, caffeine can ramp up the body’s ability to burn fat and in some cases affect power output when taken for a short period. habitual consumption is less effective in this respect.

despite its positive effects on health and mood caffeine can have negative effects for some. studies have shown that doses above 300 milligrams can have a serious impact on symptoms associated with anxiety disorders including anxiety, jitteriness, insomnia, reduced coordination. however, lower, more moderate doses are associated with reduced symptoms of depression.

caffeine withdrawal is also a real thing! if you’re a habitual coffee drinker and decide to suddenly go cold-turkey you’ll likely experience a splitting headache, become irritable, fatigued, and may even develop flu-like symptoms that can last from 1 to 3 days.

so how much caffeine is considered healthy? based on current guidelines it’s no more than 400 milligrams of caffeine per day for most adults and 200 milligrams for pregnant or breastfeeding mums.

but, with most cups ranging between 65 and 300 milligrams of caffeine per cup, we take these guidelines with a pinch of salt as we know that caffeine content is dependant on several factors; the coffee type (robusta has double the amount of caffeine than arabica); and the brewing method (that’s a whole other post!).

so there you have it — everything you need to know about caffeine! but if you want to learn more we’ve left you some reading down below.

happy sipping