
Health Effects of Coffee - snikeris
https://www.mdpi.com/2072-6643/12/6/1842
======
johnfn
I have a pet theory for why coffee has such great benefits: A lot of my
friends who are more anxious have had to stop drinking coffee because it
exacerbated their anxiety to extreme degrees. On the other hand, people with
less anxiety drink it and feel fine. So there’s selection bias at play, and
correlative studies are just picking up the benefit of not being anxious.

~~~
ghostbrainalpha
I 100% agree. *Note to anyone quitting caffeine for anxiety reasons, it takes
about a month to notice the benefit.

Another pet theory I have is that a confounding variable in these studies is
often the amount of work someone has to do, and the type of work.

Someone drinking 4+ cups of coffee likely has a reason to be that productive.
Which may result in more intellectual stimulation, a higher income, and other
differences that makes the two groups very different.

I'd like to see studies where the same individual both drank 4+ cups of coffee
everyday for 6 months, and then quit caffeine entirely for 6 months and
measure the changes in health, and output collectively but on an individual
basis.

~~~
Solvitieg
Can someone provide more information on the 1-month recovery from caffeine
induced anxiety? In my experience and from what I've read online, caffeine
withdrawal typically lasts 1 or 2 weeks.

I recently quit drinking coffee hoping I could stop grinding my teeth in the
night. It hasn't helped yet, but I quit only about 3 weeks ago.

An aside, grinding your teeth in the night is very problematic because it's
not something you can directly resolve unless you get a mouth guard. Trying to
pinpoint stressors in my life has been an arduous process.

~~~
mleonhard
I hope you're using a mouth guard every night. Tooth material cannot be
replaced.

~~~
Solvitieg
I went to the dentist recently and they recommended I reduce stress in my
life. So it's probably not that bad.

------
eloff
Normally I'm content to follow the data where it leads, but I opened this with
trepidation lest it give me a reason not to enjoy my morning coffee.
Fortunately it confirms my pre-existing biases.

I find I can never just have one cup, so I make a 50% decaf mix and have 3-4
cups spaced out over as many hours. Not only does this give a smooth and
constant hit of caffeine, but it suppresses my appetite as well and I easily
power right through from 5:30 until midday lunch. These are by far the most
productive hours of my day.

~~~
ambivalents
I often do this too, but I'm starting to feel what might be the pains of a
stomach ulcer.

Has this bothered your stomach? I'm worried about what all that coffee is
doing on my empty stomach.

~~~
credit_guy
> stomach ulcer

If you feel stomach aches, you should see a doctor and make sure you don't
have H. pylori, "the third highest cause of worldwide cancer mortality as of
2018" [1]. H. pylori is treatable with antibiotics.

[1]
[https://en.wikipedia.org/wiki/Helicobacter_pylori#Cancer](https://en.wikipedia.org/wiki/Helicobacter_pylori#Cancer)

~~~
ambivalents
Thanks for looking out, this is scary. I'll be seeing a doctor soon.

~~~
credit_guy
My mother had H.pylori, developed cancer at the stomach (and the doctors
believe it was because of H.pylori), had her stomach removed, did chemo (which
is a version of hell on earth), and she is fine now, 6 years later. But it
could all have been avoided if she had taken an antibiotic treatment.
Unfortunately, although she had tested positive for H.pylori, she was given a
non-antibiotic treatment, and that was simply not enough.

After this episode, I went to a gastroenterologist together with my wife, we
both got tested. I didn't have it, my wife did. She took the antibiotic
course, which was slightly unpleasant (leaves a metallic taste in your mouth,
I think), but it's a small price to pay to avoid a cancer that is quite deadly
(about 70% 5-year fatality rate).

------
lowmemcpu
> Habitual coffee consumption ranges from about 1 to more than 5 cups per day,
> which indicates that the daily dose is defined by something other than
> genetic reasons.

One curious question I've always struggled with is, what is a "true" cup of
coffee? I've often seen people say a "coffee" cup is 6 oz, but then I'm
confused by this:

1 US cup = 8 oz

1 Imperial (British) = 10 oz

1 Australian cup = 8.45 oz

~~~
standardUser
Brewed coffee varies so much in potency, I'm not even sure how much the
quantity of the liquid even matters. A shot of coffee that has been cold
brewed with finely ground beans for 48 hours is dramatically more potent than
a giant cup of coffee brewed quickly with less-fine grounds and hot water.

~~~
TheSpiceIsLife
From the Wikipedia article:

 _Caffeine is moderately soluble in water at room temperature (2 g /100 mL),
but very soluble in boiling water (66 g/100 mL)._

Caffeine is 33 times more soluble in hot water!

What matters more, then, is the concentration of coffee grounds to water, and
how much of that water is left in the grounds.

~~~
standardUser
This doesn't have to be academic. You can do an experiment at home. Brew a big
cup of coffee with a drip machine and drink it. Note how you feel. Then, make
a batch of cold brew and let it sit for 48 hours. Drink half as much of that
as you did the hot brewed coffee, but pease do so slowly as some people become
very uncomfortable with that amount of caffeine.

~~~
KMag
Yes, cold brewed coffee can have much more caffeine than you'd expect given
the smoothness of the taste. Back when my brother managed a coffee shop, the
first time I popped into his work and asked his recommendation, he didn't warn
me of the caffeine content. I was well habituated to caffeine, but quickly
drinking 12 or 16 oz. of cold-brewed coffee left me feeling a bit dizzy, to
the point I hung around the shop for a bit to make sure I was fine to drive.

------
notdang
Anyone drinks coffee because they like it?

Every time a coffee related subject comes up on HN, it seem that the majority
is drinking it like a drug. Aren't there people that drink it because they
like it?

I like coffee. I don't drink it for waking up. Coffee is also my hobby. I
search for good green beans, I roast it, I heavily invest in good equipment
(grinders and espresso machines) and always chasing the elusive perfect shot
of espresso. It kind of makes me sad that the majority of the people view it
as a drug and consume it as a drug.

~~~
phonypc
I imagine everyone who drinks coffee does so because they like it... else they
wouldn't drink it. Some enjoy the flavor of straight coffee more than others,
sure.

I don't really understand how getting into coffee as a hobby makes it any less
of a drug. You're still consuming caffeine. There's just as much of a hobby
scene around marijuana; hobbyists are still consuming THC.

------
zwieback
Also, apparently coffee drinkers want coffee more than they actually like it:

[https://digest.bps.org.uk/2020/06/22/heavy-coffee-
drinkers-w...](https://digest.bps.org.uk/2020/06/22/heavy-coffee-drinkers-
want-coffee-a-lot-more-than-they-actually-like-it/)

Research method seems sketchy to my engineering mind.

~~~
mumblemumble
That's more-or-less in line with my personal experience.

I usually drink tea, because I like a hot beverage, but find that my quality
of sleep and overall sense of wellbeing tends to suffer if I drink coffee.
Even when I only drink it in the mornings.

But I do still like (don't love, but like) coffee, and most cafes and
restaurants in my part of the world can't make a decent cup of tea to save
their lives, so I often just drink coffee when I'm traveling. And I find that,
even after only a few days of drinking coffee, I will experience 2 or 3 days
of cravings once I get back home and return to my regularly scheduled pot of
dragonwell.

~~~
zwieback
That's me as well, I drink tea at home, coffee at restaurants. Luckily a lot
of coffeeshops now make a decent cup of tea as well, especially here in the
Northwest.

------
FakespotCom
FYI: "H.K. received fees for providing consultant services to Tchibo GmbH.
K.K. and S.M. reported no conflicts of interest."

One of the main authors was compensated by the largest coffee retailer in
Germany.

~~~
gen220
Apparently, many such coffee studies are sponsored by firms with an interest
in publicizing coffee's benefits. It doesn't mean the science _necessarily_
isn't good. Although, consider the opportunity cost: we could instead be
researching many other things that don't carry as high a cost as coffee (in
terms of production labor, refining, and transportation), and may commute even
greater benefits. Of course, we shouldn't expect big corporations to sponsor
that kind of research, because it's not in their interest.

It _is_ decidedly in the interest of coffee conglomerates to demonstrate that
coffee is good for society, because it justifies the great fiscal and human
expenses they go to, to bring fresh coffee to your breakfast table. Not
passing judgement either way, it's just an interesting lens to consider.

There was a nice article in the new yorker a couple months ago on the subject
of society's shifting moods towards coffee, and how it's materialized in the
literature and science. [https://www.newyorker.com/magazine/2020/04/27/the-
war-on-cof...](https://www.newyorker.com/magazine/2020/04/27/the-war-on-
coffee). One of the reviewed books: [https://www.amazon.com/Coffeeland-Mans-
Empire-Making-Favorit...](https://www.amazon.com/Coffeeland-Mans-Empire-
Making-Favorite/dp/1594206155).

Edit: oh boy. I misread the parent comment. I thought they _had_ declared a
conflict of interest. Sorry. I didn't intend for my comment to read as a
corporate-research apologia.

~~~
coldtea
> _Apparently, many such coffee studies are sponsored by firms with an
> interest in publicizing coffee 's benefits. It doesn't mean the science
> isn't good._

Usually the science isn't good even with no conflicts of interest, with 80% or
more of studies being non-reproducible BS full of errors and cherry-picking.

Now consider the percentage when there's also conflict of interest...

~~~
ksk
How did you arrive at your 80% number?

~~~
coldtea
[https://en.wikipedia.org/wiki/Replication_crisis](https://en.wikipedia.org/wiki/Replication_crisis)

[https://www.smithsonianmag.com/science-nature/scientists-
rep...](https://www.smithsonianmag.com/science-nature/scientists-
replicated-100-psychology-studies-and-fewer-half-got-same-results-180956426/)

[https://www.wired.com/2013/04/brain-
stats/](https://www.wired.com/2013/04/brain-stats/)

[https://www.nature.com/news/over-half-of-psychology-
studies-...](https://www.nature.com/news/over-half-of-psychology-studies-fail-
reproducibility-test-1.18248)

[https://phys.org/news/2018-07-beware-scientific-
studiesmost-...](https://phys.org/news/2018-07-beware-scientific-studiesmost-
wrong.html)

~~~
ksk
Looked at the links, didn't find anything relevant to address my question. I
don't consider "may be" to be data, you seem to have a different opinion.

------
Angostura
I really like thye kind of articles that the NHS does on this
[https://www.nhs.uk/news/food-and-diet/drinking-3-4-cups-
coff...](https://www.nhs.uk/news/food-and-diet/drinking-3-4-cups-coffee-day-
may-have-some-health-benefits/)

~~~
baxtr
_> Drinking 3-4 cups of coffee a day may have some health benefits_

:-)

------
brunoqc
I'm surprised there's no problem because of the roasting process. It's kinda
burning it. Isn't burnt stuff carcinogenic?

~~~
hprotagonist
Coffee roast temperatures are about 350 degrees.

do you worry about getting cancer from bread? Bread ovens are about 200F
hotter.

~~~
cl0wnshoes
Coffee roaster here, at 350F the beans have turned yellow and barely started
browning. 390F~ is around the point where most roasters would consider
development of flavor to really take off (yeah yeah pre-development phase, I'm
keeping it short) and beans will be done at various points after that
depending on roast preference.

The smoke that the roaster produces towards the end of roast is no joke, and
some has to get on the beans, but I'd say it is minimal enough to not be an
issue as there should be plenty of air flowing through the roaster at that
point.

If roasted improperly oils could seep out of the beans while in the roaster
which burn as well and stick to the beans. I'd say that is more of an issue
than the smoke or roasting too dark.

------
winrid
Coffee/caffiene is only really useful to me when I have to do something I
hate.

Otherwise I'm more productive without the crash.

~~~
techsin101
Finally someone who feels like me. I drink like once every two weeks. But only
when I'm too exhausted and needed to do something yesterday. I don't like
feeling weird as I do when after 3-4 hours of coffee like I'm having a high
blood pressure or feel consciousness changing.

~~~
winrid
Ha, well, hello.

Feeling the elevated heart rate while being tired and not able to take a nap
indeed sucks. I get why people just start drinking 3-5 cups a day.

------
__s
Did a search on claim "Coffee plays a dominant role in that regard because it
is the major dietary source of phenolic acids and polyphenols in the developed
world": [https://www.healthline.com/health/polyphenols-
foods](https://www.healthline.com/health/polyphenols-foods)

Granted it's suggested to cook these a bit to maximize absorbtion because cell
walls & things

------
ipunchghosts
Is this a reputable paper? I am an academic and quit reviewing for MDPI 2
years ago because the quality of the initial submissions was so low.

------
kgin
It’s amazing how much people want coffee to be bad for you. That’s been a
constant for at least hundreds of years.

------
monkeycantype
I didn't start drinking coffee until my late thirties, and feel as if I have
had too different lives before and after. My life with coffee is happier,
successful, productive, contented. If i had objective data, I think you would
see it was more regularly patterned with respect to sleep, work, exercise. I
think for me it was a little nudge across a transition threshold. I doubt
coffee is bringing a huge health benefit on its own, and I reject the 'anyone
can make it if they try attitude', but as a smart enough, healthy enough,
lucky enough person in a wealthy country, my fate was very much bounded by my
own lack of consistent organised disciplined effort. A little bit of coffee
nudged my behaviour in a direction that has made me happier, and perhaps
ultimately healthier.

------
nsl73
The abstract says that the majority of the benefits of coffee probably comes
from phenolic phytochemicals. This implies you can receive all of the same
health benefits like lower risks type 2 diabetes by eating other vegetables.

Is the western diet really so weak that coffee is a major source of our
vegetable intake?

~~~
gridlockd
If people generally liked to eat vegetables, it would not need so much
propaganda.

I think the evidence that vegetables are all that healthy is not that great
and the statistical effects are not large.

Phytochemicals may be hormetic stressors, or they may just be stressors most
bodies can deal with, but do not actually benefit from. Antioxidants in
particular seem to not live up to expectations.

------
madarcho
Interesting to me, that this is the first time I am hearing of lowered disease
risk from regular coffee, which the study points out "has been confirmed in
prospective cohort studies in many regions of the world".

The way I understood it, the study aims to correlate benefits with the "plant"
contents of coffee. What would be interesting to me is to see more about the
effect of the roast. The study touches on it in a couple of points ("Phenolic
Phytochemicals in Coffee May Account for Health Effects" where a darker roast
produces more phenolic components), but I could do with something more
specifically targeting the roast differences.

------
OliverJones
This is a complex scientific way of saying "coffee is a vegetable."

Let's hope politicians with influence over school lunch menus don't misuse
this result.

------
liquidify
I can't drink coffee because I have a nickle allergy and it makes my skin on
my fingers get bumps all over them.

------
aj_g
Has anybody here experimented with coffee substitutes (such as
[https://www.cookinglight.com/good-food-fast/mud-wtr-
mushroom...](https://www.cookinglight.com/good-food-fast/mud-wtr-mushroom-
coffee-review) )?

~~~
makerofspoons
I'm a fan of Postum. Interested in trying this mushroom coffee though I'm
concerned about the footprint of where they get all of their ingredients.

------
shock
It looks like CYP1A2 gene polymorphisms correlate with increased risk of non-
fatal miocardial infarction:
[https://pubmed.ncbi.nlm.nih.gov/16522833/](https://pubmed.ncbi.nlm.nih.gov/16522833/).

------
makerofspoons
Has there been a study that weighs benefits from studies of coffee consumption
against the societal health impacts of coffee production? I mean we have
coffee farmers developing kidney disease
([https://pubmed.ncbi.nlm.nih.gov/24878647/](https://pubmed.ncbi.nlm.nih.gov/24878647/))
and the environmental impact of its cultivation and shipping
([https://www.sustainablebusinesstoolkit.com/environmental-
imp...](https://www.sustainablebusinesstoolkit.com/environmental-impact-
coffee-trade/)). It's the second most tradeable commodity after oil but as
it's largely unnecessary for society to function. I would doubt it would come
ahead as a net positive for humanity.

~~~
baxtr
Where would you start and where would you end the analysis? What about for
example the endless number of families that rely on coffee as income in
developing countries?

~~~
makerofspoons
One could start by analyzing if the economic benefit of growing it and the
healthcare savings of consuming it actually outweigh the long-term damage of
its production. My hypothesis is once you strip away subsidies that allow
farmers to clear forest for cultivation and fuel subsidies for shipping it
across the ocean or by plane the hidden costs start to add up.

------
rantwasp
for what is worth this has been known for a while (lookup Stanford medicine
study). what’s interesting is that 4-5 cups per day is better than 1-2. also
there is speculation that it’s not the caffeine but other things in coffee
that have beneficial effects.

i also suspect that large coffee consumption is better if you compare people
that don’t get enough sleep (as someone that does not drink coffee will have a
better quality of sleep - unless you drink 5 cups in the morning)

------
a0-prw
Reading the comments I've noticed a lot of people talking about addiction... I
have for years had the habit of starting the day with 3 to 4 cups of strong
coffee, either plain or with cream. I was pretty sure I was "addicted". Until
the time, after about 2 weeks, when I noticed that the new brand I had quickly
grabbed and happily consumed every day for 2 weeks was decaf. What you tell
yourself is far more important and stronger than "addiction".

------
newfeatureok
If coffee is healthy (like the article suggests) because of the "plants"
wouldn't tea be even healthier?

------
barrenko
I view coffee as absolute evil, but necessity for any kind of office type
work.

~~~
iso8859-1
Why is it necessary? Do you fall asleep without coffee? Or do you just not
feel productive without it?

~~~
barrenko
I just have trouble starting intellectual tasks without coffee, probably
psychological or something.

------
znpy
i wonder how coffee compares to tea in that sense.

