Today we're gonna talk about caffeine. It's the most widely
consumed psychoactive drug in the world, most commonly
consumed as coffee. And we're all familiar with
the effects of caffeine but what exactly is caffeine? Why do plants produce it? What does it do to our bodies and is it good for you? Now, from a chemical perspective, caffeine can be described
as both a methylxanthine and an alkaloid. The first name refers to the shape and composition of the caffeine molecule while alkaloids as a
whole are a broader group of naturally occurring organic compounds, defined by having at
least one nitrogen atom. Alkaloids have many functions and effects but almost all are bitter in taste. Caffeine occurs naturally in
more than 60 different plants but more surprising then that is that those plants each develop different biochemical mechanisms and pathways to create caffeine. This is a phenomenon known
as convergent evolution. Most people associate caffeine with coffee and it is named for coffee but it also occurs in tea, chocolate, kola nuts, guarana seeds and even the flowers of citrus plants. Plants produce caffeine
primarily as a pesticide. It deters insects from
attacking or eating the plant, in part with its bitter taste, but caffeine is also toxic
to some herbivore insects. It does also have one
super interesting function. Studies have shown that caffeine can improve the memory of bees, helping them create a stronger association between the smell of a coffee flower and its sweet nectar. This might be why caffeine exists in very low concentrations in the nectar of certain flowers,
like the citrus flowers we mentioned before. It gives those plants
a competitive advantage in the world of pollination. Human consumption of
caffeine likely starts back in 3,000 B.C. with the consumption of tea. And tea, gram for gram, has more caffeine than coffee but we just use more
coffee when we make a cup. The beginning of coffee consumption is a little bit harder to pinpoint but by the middle of the 15th century, we're pretty confident
that coffee drinking had taken hold in Yemen
and the surrounding areas. With both tea and coffee, very early records shows
that people liked it for the stimulating
properties of caffeine. Credit for the discovery of caffeine is not quite clear cut. In 1819, a German chemist
named Friedlieb Ferdinand Runge isolated what he called kaffebase, a nearly pure caffeine extract. He did this work apparently at the suggestion of the famous writer, Johann Wolfgang von Goethe. Runge is also notable for having been the
first to isolate quinine and also for the invention
of paper chromatography. In 1821, it was discovered independently by French chemist Pierre Jean Robiquet to whom caffeine's
discovery had traditionally, historically been credited. It was also discovered at the same time by two other French
chemists working together, Pierre-Joseph Pelletier and Joseph Bienaime Caventou. Pelletier was the first
to use the word caffeine in print, though Robiquet was the first to isolate and describe the properties of pure caffeine. In that pure form, caffeine is a white, crystalline powder that has a pretty bitter taste. If you take a large
enough dose, it's toxic but in lower doses, if you look at how it affects humans, you start to understand
its enduring popularity. Now, most people consume caffeine by drinking coffee and
it's absorbed initially through the gastrointestinal tract and then 30 to 60 minutes
after consumption, that's when it reaches peak
concentrations in the body. Let's get into some biology here. Now, caffeine affects the body with three different mechanisms. Firstly, caffeine blocks
the receptors in the body for a compound called adenosine. Under normal circumstances, adenosine triggers these receptors and it produces a feeling of relaxation and even drowsiness for some people. And so caffeine prevents
this from happening, while also causing the
body to increase production of dopamine and noradrenaline. This is the mechanism behind most of the effects that we all
experience with caffeine, this inhibition of adenosine. It happens at relatively low doses and gives us that feeling of wakefulness or alertness that we associate
with a cup of coffee. This mechanisms might
also explain the kind of caffeine crash that
many people experience with a sudden feeling of
tiredness and exhaustion. It might be that once
the body metabolizes all of the caffeine, then the adenosine is finally able to trigger those receptors and really, really make
us feel tired and drowsy. Caffeine also causes
the release of calcium inside of muscle cells and it can prevent or slow its reuptake. This increased availability of calcium increases the power output of the muscles but it does require a
pretty large dose to occur, around 500 milligrams
for an average person. Caffeine can inhibit what
are called phosphodiesterase, now, if you stop these
enzymes working properly, then you can actually cause the body to burn more fat. But for this to work, it also requires a much larger dose than people would typically get from drinking a few
cups of coffee in a day. Caffeine affects the
central nervous system. Caffeine makes us feel
more alert, more awake and has been shown to improve memory. However, the beneficial
effects of caffeine aren't as clear cut as we would like. Several studies have now shown that that improved mental
clarity that we get when we drink coffee in the morning, well, that comes from alleviating
our withdrawal symptoms, rather than actually improving
our cognitive functions. One positive impact is
the increasing evidence for caffeine's ability to
act as both a treatment for some aspects of
Alzheimer's and Parkinson's, as well as having some
preventative properties as well. Now, caffeine could be said to be the last legal
performance-enhancing drug but it wasn't always this way. Between 1984 and 2004,
caffeine was actually on the Olympic Committee's banned list. If they tested your urine and you were at a higher concentration than 12 micrograms per
milliliter, you were out. And to hit that level, you could do it with
just five to eight cups of coffee in the morning. And because people metabolize
caffeine differently, this was ultimately an
unfair thing to police and after 2004, it was
off the banned list. Now, as we talked about before, caffeine does affect the muscles, it does affect power output but it does seem less effective with habitual users of caffeine. Though it does impact the perception of exertion and fatigue, which is kind of interesting. For people using caffeine for sport, they're typically dosing
three to five milligrams per kilo of body weight. Now, not everyone has a positive
experience with caffeine and we do need to talk about that. Symptoms like mild anxiety, jitteriness, insomnia, reduced coordination, these are all symptoms people can suffer with even mild caffeine consumption. Caffeine can have a negative
effect on anxiety disorders and doses above 300 milligrams can worsen someone's anxiety. However, lower, more moderate doses have been shown to be associated with reduced symptoms of depression. Consuming coffee regulatory
does leave you susceptible to experiencing caffeine
withdrawal if you stop suddenly. Now, most people can
experience a big headache that can last a little while. They can become irritable, fatigued, some can get flu-like symptoms
or struggle to concentrate. Typically these symptoms will last for up to 24 hours, though occasionally, it can go on for longer and people have experienced
caffeine withdrawal for up to three days. So how much caffeine exactly
is considered healthy? Recommendations are quite broad because people respond to and metabolize caffeine
a little bit differently but current guidelines are for an adult, it's no more than 400
milligrams of caffeine per day. And that's 200 milligrams if you're pregnant or breastfeeding. Soft drinks, energy drinks, tea are all popular sources of caffeine but coffee is by far the most popular. But with soft drinks and energy drinks, there is typically a fixed and known amount of caffeine in them. You can look up on the
internet how much coffee is in a can of Coca-Cola. With coffee, you can't. A cup of coffee will have
quite a dramatic variance in its caffeine content, depending on a number of factors. The coffee itself will play a role. Arabica has half the
caffeine content of Robusta but the recipe or the
way that it was brewed, these will all have an impact. And they've gone and done tests and bought coffees from different cafes and there's been a pretty
wide range reported, anywhere from around 65
up to over 300 milligrams in a single cup. Various governments and governing bodies have tried a few times to legislate coffee companies to have them tell you
exactly how much caffeine is in your coffee-related product but so far, that's never happened. It's always been
successfully lobbied against. Excessive caffeine consumption can be quite unpleasant and actually, it can be fatal. To reach caffeine toxicity, you'd have to ingest around
10 grams of pure caffeine in a day. To do that, you'd have to drink between 50 and 100 cups of coffee. So it's actually pretty rare that anyone reaches that
from drinking coffee. More often, people have died
from caffeine intoxication from consuming too many caffeine pills or other medications that
may contain caffeine. I think for those of us who drink and enjoy coffee all the time, it's really important to understand a bit more about caffeine. This is a psychoactive drug that we're taking every single day. We should understand what it is and how it affects us. Now, I know you'll probably have questions about decaf and decaffeination and I promise, I'll answer
them all in a future video. And if you wanna know more about caffeine, I've left you some reading down in the description below. But for now, I'll say thank
you so much for watching and hope you have a great day.
So... I'll be safe if I control myself and don't drink 50+ cups of coffee a day.
I'll try!
Nice and succinct overview of the chemistry and pharmacology! You do such a good job of distilling information without oversimplifying. And giving links/info to encourage people to dig deeper if they’re interested.
Have you listened to the “In Defense of Plants” podcast? The host does some crossover episodes with another podcast called “This Podcast will Kill You,” where they talk about plants and pharmacology. Here’s a link to an episode they did about caffeine.
You clearly made this video to show off your animated infographic skills, right?
I love these informative non-product related videos (even though personally I probably watch them less since they reqiure a bit more attention). Learning about coffee's history and science is very rewarding and as someone who isn't going to buy an espresso maker or a new grinder soon, these are also more applicable to all of us
Everyone else in to discuss caffeine and pharmacology... I just want to say James' sweater game remains on point. Particularly loving the green today. That pattern is fantastic.
Wonderful video - I’m a pharmacist & this video had a lot of info I didn’t know about the stuff. The effect on bees is super interesting & I wasn’t aware of the effect on muscular contractile properties. Thanks as always James!
I love Hoffmann's videos and i miss a lot the videos like "What no one tells you about learning to taste" i found that one really awesome because for years i felt that way then after that video i opened up a little bit and started drinking bad coffee hahaha so i can appreciate the really good one.
You get an A+
The animations are really beautiful.
For anyone wondering how alternative takes on this topic look like:
6 things you (probably) didn't know about caffeine posted 2 weeks ago by Seven Miles Coffee Roasters
How To Drink Coffee For Better Health posted today by European Coffee Trip
coincidence? probably!