Katie O. asks: How much coffee would someone
have to drink to be fatal?
There have been numerous deaths attributed
to excessive caffeine ingestion.
So if you happen to be a person who loves
coffee and energy drinks, you might want to
know approximately what amount you should
avoid drinking on a given day.
So how much caffeine would it take to kill
you?
Well, there are several factors that make
this a tricky question to answer.
For example, not everyone reacts the same
way to caffeine.
People also become tolerant to it and so the
effects can be different from person to person.
Lastly, there would be no respectable researcher
who would dare perform a study on humans if
the goal of that study is death to the person.
Thus, as you might expect, we couldn’t find
any studies that show what amount of caffeine
would definitively kill your average human.
But that’s not very interesting, so let’s
dig a little deeper, shall we?
First, we went ahead and gathered 100 volunteers
who were tired of living, along with some
who we just found on the streets and figured
they should have been staying quarantined,
so what would happen next in our study is
really on them…
But more seriously, it turns out there are
less ethically questionable studies that have
allowed doctors to understand what's going
on inside the body in caffeine overdoses and
approximately what dose would prove fatal
for the average person.
So while the exact dose is almost impossible
to answer for a given individual, we can say
for sure a few things, like that the highest
caffeine dose ever known to be ingested by
someone who survived was around 100 grams.
Although that might not sound like that much,
in terms of raw amount of caffeine, it should
be noted that that's the amount of caffeine
in about 1,200 cups of coffee!
Lesser doses that are generally thought to
put an adult at high risk of death typically
range from about 5-10 grams ingested in a
short period, which is still an awful lot
of energy drinks and/or coffee, though there
are certain diet pills that can easily get
you over that amount in just a handful of
pills.
Of course, people ingesting significantly
lesser doses have had death attributed to
caffeine overdose.
That said, others survive where you’d think
they wouldn’t, such as one medical report
looking at the case of an unnamed one year
old girl who ingested some of her mother’s
diet pills.
The total dose of caffeine to the one year
old was approximately 3 grams.
While said baby did have significant complications,
including heart issues and seizures in the
immediate aftermath, she survived the incident
and did not seem to suffer from any long term
issues.
Noteworthy here is that due to her tiny size,
the caffeine concentration in her system ended
up being the second highest every documented
in someone who survived the event.
Yet another research paper we looked at documented
the case of a 16 year old boy who ingested
around 6-8 grams of caffeine and also managed
to survive, despite a number of immediate
medical complications as a result of the caffeine.
So basically, there are a myriad of factors
at play here, but as for a definitive dose
that would kill most people, it turns out
when talking cups of coffee or energy drinks,
it’s a huge amount in most people, with
some exceptions where individuals with certain
heart conditions and the like might want to
avoid significantly smaller doses.
As for the average Joe, most physicians and
medical bodies tend to recommend avoiding
ingesting more than around 500-600 mg of caffeine
per day, not necessarily because you might
die per se, but more because it’s likely
not going to be good for you for a variety
of reasons, especially if done regularly.
For reference, the average cup of coffee has
in the range of 40-150mg of caffeine.
For example, a Starbucks 2x Caffeine K-cup
will get you a dose of around 260 mg, compared
to 
the normally caffeinated k-cup from the same
brand which has around 130 mg.
Obviously if following the recommendations,
you’ll want to avoid more than 2 of the
2x caffeine k-cups per day.
For other references, 12 ounces of Jolt cola
has approximately 100mg (16 oz at about 160
mg), Monster Energy at about 160 grams, 12
oz of Mountain Dew has 55mg, and Dr. Pepper
has 61 mg.
So this all might have you wondering how caffeine
actually manages to kill?
Caffeine is one of several naturally occurring
substances known as Xanthines.
Xanthines are 
among other things, central nervous system
(CNS) stimulants.
Caffeine, specifically, is in over 60 known
plant species.
It's the most widely consumed psychoactive
substance in the world.
Depending on which study you read, approximately
80-90% of the US population consumes at least
200mg per day.
In low doses, it has many benefits that can
help with things like pain management, water
retention, alertness, and a general feeling
of wellbeing, to name a few.
As with most CNS stimulants, the higher the
dose, the more profound the reaction.
As you consume more caffeine, the risks begin
to outweigh the benefits.
A person can become jittery, anxious, begin
having high blood pressure, chest pain, headaches,
dehydration, and unfortunately, dependence
that causes withdrawals if you don't continue
consuming it.
In toxic doses, caffeine can cause extremely
low blood pressures, seizures, cardiac rhythm
problems, and lactic acidosis.
While there appears to be some dissension
among researchers as to exactly how xanthines,
like caffeine, cause the reactions they do.
What is known is that they antagonize what
are known as adenosine-receptors within almost
every cell in the body.
Adenosine is a chemical present in every human
cell.
It combines with other chemicals like phosphate
to create numerous compounds that help cells
work properly.
Those compounds need to attach to their receptors
to affect cells.
There are 4 main groups of adensonine receptors
within the body and their effects can fall
into four categories.
Generally speaking, adenosine compounds help
in increasing the oxygen available to cells,
protect against the damage caused by a lack
of oxygen, help in initiating the body's natural
anti-inflammatory responses, and help in the
creation of blood vessels.
Caffeine is similar to adenosine in chemical
composition, and as such, can attach to adenosine
receptors not allowing adenosine compounds
to perform normally.
The result is CNS and cardiac stimulation,
relaxation of the smooth muscles, and a diuretic
action on the kidneys that can lead to dehydration.
Thus, in high levels, caffeine can be very
toxic.
It will bind to adenosine receptor sites known
as subtypes A1 and A2.
The result is seizures.
In high doses, it will also inhibit an enzyme
known as phosphodiesterase, while stimulating
the release of neurotransmitters involved
in your fight or flight nervous system.
The result is extremely fast heart rates,
dilation of your blood vessels causing low
blood pressures, low potassium levels that
can cause lethal heart rhythms, the breakdown
of sugars in your liver, and an increase in
your white blood cells.
If all that doesn't seem like it's deadly
enough, those side effects will cause their
own problems.
Specifically, lactic acidosis will be caused
by your body's tissues not getting enough
oxygen because your blood pressure is too
low.
The result of your seizures, low oxygen levels
within your cells, and an inevitable calcium
release from an area of your cells called
your endoplasmic reticulum will give you what
is known as rhabdomyolysis- this is a breakdown
of your muscles causing a release of your
muscle fibers into your bloodstream (brown
pee and clogged kidneys anyone!).
If you're thinking “I'm never drinking that
nectar from Satan again”, don't worry, those
toxic reactions won't happen at normal consumption
levels.
Just, again, when you start getting in excess
of 500-600 mg per day for a typical adult,
you’re going to start to have a bad time
in many cases.
And even less for the littles.
Bonus Fact:
Speaking of Satan, prior to being baptized
in the 16th century by Pope Clement VIII,
coffee had been thought by many Catholic leaders
in Europe to be Satan's drink.
Whether because of its characteristic dark
color and bitter taste (both of which were
the antithesis of sweet wine, which was associated
with the Eucharist and Christ), its physical
effects, or its roots in the Muslim world,
or all three, many Catholic clerics were solidly
against the beverage.
As to who first brewed the first cup of Joe
isn't known, but that hasn't stopped many
a fictitious origin story from popping up,
such as the commonly repeated legend that
coffee was first "discovered" in the 9th century
by an Ethiopian herdsman, Kaldi who noticed
that one of his goats appeared to be particularly
frolicsome after consuming some red coffee
berries.
Giving it a go himself, he soon felt more
upbeat.
Energized, he relayed his discovery to his
neighbors and coffee consumption was born.
However it really came to be discovered as
a stimulant, over time, coffee became popular
throughout Ethiopia, where it was said that
warriors of the Galla tribe mixed it with
butter and ate it before going into battle.
Eventually, by the 12th century Arab traders
returning to what is now Yemen from Ethiopia
brought coffee with them and learned to cultivate
the plant.
By this point, the beans were being transformed
into a drink (qahwa or kahwah) by means of
boiling.
In the 15th century, Ottoman Turks brought
coffee with them when they conquered Constantinople
(Kostantiniyye or al-Qustantiniyah).
At this same time, the Mufti of Aden, who
had been suffering with an unidentified illness
and was cured after drinking coffee for the
first time, touted its beneficial qualities,
which contributed to its popularity throughout
the Muslim world.
Also in the 15th century, the first coffee
houses (Kaveh Kanes) began appearing in Mecca
and Constantinople, and like today, they were
used for not only drinking coffee, but socializing
as well.
By the end of the 16th century, coffee was
found in Venice, and by the turn of the 17th
century, Catholic Church leaders were becoming
suspicious of coffee and the effect it had
on the local populace.
Deciding it must be Satan's drink, many local
clergy beseeched the pope, asking him to prohibit
its consumption.
Trying it for himself, Pope Clement VIII (1536-1605)
found it agreeable, and demonstrating a gift
for diplomacy, declared in 1600:
“Why, this Satan's drink is so delicious
that it would be a pity to let the infidels
have exclusive use of it.
We shall cheat Satan by baptizing it.”
With the pope's blessing and its natural addictive
qualities, coffee soon spread across Europe.
