Habitual coffee intake shapes the microbiome, modifies physiology and cognition

https://www.nature.com/articles/s41467-026-71264-8

by scubakid • 3 months ago

276 269 3 months ago

neya3• 3 months ago

The only good thing that keeps me from collapsing into a state of limbo is coffee and now, even that's bad (seems more like a mixed bag, but still)? Sigh.

bee_rider• 3 months ago

There have been positive and negative reports for a long long time. If coffee was going to kill us, I’d certainly have died in school!

kulahan3• 3 months ago

Coffee in general is unreasonably healthy as a beverage. The overwhelming majority of science agrees it’s a quality health drink.

modo_mario• 3 months ago

Non-industry funded science?

anon848736282• 3 months ago

Don't fret. You're allowed to enjoy things that aren't part of the scientific reductionist longevity influencer lifestyle fad :)

antonvs• 3 months ago

Nitpick: What you’re referring to is not scientific.

cyberpunk• 3 months ago

Maybe I have some neurological issue or something but whenever I quit coffee I find it extremely difficult to maintain any kind of motivation to sit in an open plan office and code. Coffee makes me a worker bee, I can understand why employers give it away for free.

So, the coffee stays for now.

neya3• 3 months ago

Yeah, exactly. I can totally relate to this. I have actually monitored my productivity on an excel sheet and the days with coffee win by a large margin. I am not sure if it's withdrawal symptoms on the days without, though.

hermitcrab2• 3 months ago

Relax. Tomorrow there will be a paper/article saying coffee is great for you.

fransje26• 3 months ago

Did you know:

    By replacing your morning coffee with herbal tea, you can remove up to 87% of the little joy you still have left in your life.  /s

Keep the coffee buddy.

neya3• 3 months ago

Haha, that was a funny quote!

Izkata• 3 months ago

Never forget the Time Travel Dietician (4 minutes): https://www.youtube.com/watch?v=5Ua-WVg1SsA

getnormality• 3 months ago

Coffee modifies physiology and cognition? You're telling me this for the first time.

ButlerianJihad3• 3 months ago

I was so surprised at this headline that I nearly leapt out of my chair!

jonplackett• 3 months ago

But it says it’s the same for decaf. That is more interesting

triage8004• 3 months ago

Humans known since 45 minutes after first drink

alecco• 3 months ago

The paper is about previously unknown ways coffee affects the body.

reedf1• 3 months ago

At least subjectively, coffee seems to help my memory. But maybe that's why I started drinking coffee?

I would probably drop coffee it was proven to have negative effects on memory.

bboozzoo• 3 months ago

But maybe that's why I started drinking coffee?

you don't remember why, do you?

layer8• 3 months ago

I’m drinking to forget. ;)

6LLvveMx2koXfwn2• 3 months ago

"These findings reveal previously unrecognised effects of coffee on the microbiota–gut–brain axis, suggesting that microbiome profiles could potentially predict coffee consumption patterns", or, perhaps, just ask the patient?

raincole• 3 months ago

Could you elaborate on how to interpret your comment without it leading to anti-intellectualism?

6LLvveMx2koXfwn2• 3 months ago

It was a joke

colechristensen2• 3 months ago

You are missing the point.

If you can predict someone's coffee intake based on testing of their microbiome then you've proven that coffee intake has predictable effects on the microbiome.

The important part isn't predicting coffee use, it's just the proof that there's you can predict and perhaps control in the opposite direction leading to more research.

wjnc• 3 months ago

I have not much followed the science of gut microbiome and psychology. Is this really going where this article is pointing? That we can tease out causation in foods and habits via gut microbiome towards behavior and psychology? Pretty rad.

colechristensen2• 3 months ago

Yeah there's nontrivial evidence that among other things, the complex community living inside you manipulates your brain.

ButlerianJihad3• 3 months ago

My psychiatrists agree that “hallucination” (in lay terms: “hearing voices” or “seeing things”) only refers to things that aren’t real.

chneu• 3 months ago

There's a decent amount of research going into the hormones that our GI biome produce and how it affects us. Our body has a few different biomes and they all seem to play somewhat important roles.

poly2it• 3 months ago

... reintroduction triggered acute microbiome changes independent of caffeine.

This sounds interesting. I've never really considered the constituents of coffee other than caffeine and what unique effects they may bring.

I wonder if I would experience behavioral effects if I replaced my coffee intake with caffeinated non-coffee drinks or pills?

kulahan3• 3 months ago

Studies seem to indicate that coffee is at least as healthy, if not healthier than tea, and I have not heard this about caffeine specifically (aka the same effects coming from pills or energy drinks).

One fun fact: we still haven’t figured out why coffee makes us poop. We’ve studied every chemical in there and can’t seem to find a link, but the association is uh… well-known.

hermitcrab2• 3 months ago

why coffee makes us poop.

That seems to vary wildly between individuals. It doesn't have that effect on me.

pinkmuffinere• 3 months ago

I’m super interested in this sort of study! However, it looks like n=62 here, which I think weakens the results —they’re probably just useful as suggestions of possible effects. Also, any food is expected to have similar effects on the microbiome. They didn’t test caffeine in isolation. In some ways that’s better (I don’t consume caffeine in isolation), but in some ways that’s less useful (it’s possible you get similar results from many random vegetables)

sixtyj• 3 months ago

In 1995, NASA did spiders experiment. Caffeine is a siginificant impulsivity trigger. :)

https://rarehistoricalphotos.com/nasa-spiders-drugs-experime...

jayd163• 3 months ago

Nice web, Mr. Crack spider.

ivell• 3 months ago

LSD has unconnected strands in the air. I guess this is expected.

ButlerianJihad3• 3 months ago

Warning: those photos in the dot-com website are negative images, not the original black-on-white. Lousy with animated ad banners, too.

https://ntrs.nasa.gov/api/citations/20100033433/downloads/20...

Don't ask me why some blogger posted the PDF in 2013, and also don't ask me how English Wikipedia editors determined that a Wordpress blog is a "Reliable Secondary Source". I did locate the original on NASA's own website. Public Domain (USGov).

bhaney• 3 months ago

They didn’t test caffeine in isolation

But they did test both caffeinated and uncaffeinated coffee, and found the same effects in both, indicating that the effect is caused by something in coffee other than the caffeine

krige• 3 months ago

Doesn't decaf also contain caffeine, just a lot less of it?

anon848736282• 3 months ago

Typical extraction yield is 18-20%. For a 20g dose that's 4g of material consumed, or about 30 individual beans.

I wonder if you could find similar effects with 4g or broccoli sprouts, or garlic, or ginger, or cumin seed, shiitake mushroom, seaweed, soursop leaf, or...

satvikpendem2• 3 months ago

What's cool is this effect exists even in decaf coffee, as someone who primarily drinks decaf black, for flavor and for a good night's rest as I'm sensitive to caffeine.

Kelteseth• 3 months ago

What kind of decaf coffee do you drink? There are differences between the cheap chemical Methylene way to create decaf coffee and the expensive co2 way to get rid of the caffeine.

https://cleanlabelproject.org/wp-content/uploads/CLP-Decaf-C...

satvikpendem2• 3 months ago

I don't buy the methylene processed ones, generally it's Swiss water processed or like you said the CO2 processed ones.

Schlagbohrer• 3 months ago

Is that methylene way even legal? It basically uses petroleum fuel in the process right? I assume it was outlawed a long time ago but that might be extreme naievete for US regulatory capability...

IAmBroom6• 3 months ago

I'm pretty sure I'm allergic to methylene-decaffeinated coffee. I discovered in the early 1990s that I'd get sneezy almost every time I drink decaf office coffee, but my home decaf didn't do that to me.

Hasn't happened in a long time, probably due to (1) avoiding cheap decaf and (2) the banning of meth-coffee (heh) in the US.

testemailfordg2• 3 months ago

Funded by the Institute for Scientific Information on Coffee (ISIC) — an industry body — which is a notable conflict of interest the authors disclose but don't extensively discuss

rapidaneurism• 3 months ago

It does not sound like an outcome that big coffee paid for it to be so:

Behaviourally, coffee drinkers exhibited greater impulsivity and emotional reactivity, whereas non-coffee drinkers demonstrated better memory performance.

selcuka• 3 months ago

It does not sound like an outcome that big coffee paid for it to be so:

Who said anything about big coffee? These guys might be a secret, anti-coffee organisation. /s

iammjm• 3 months ago

Do they though? Any data on that? Also, the highly caffeinated people might also be sleep deprived, which impacts memory and emotional regulation

fc417fc8024• 3 months ago

Ah yes, yet another in the long line of results which confirm our suspicion of water being wet to have been right all along. In this case it's something that anyone who has spent a significant amount of time around routine coffee drinkers and regularly consumed it themselves already took for granted.

zug_zug• 3 months ago

Or, maybe this is the cleaned-up interpretation

culi7• 3 months ago

The first paragraph of the introduction touts all the health benefits of coffee.

I don't necessarily deny these benefits but it feels weird for a scientific paper to hedge its bets like this.

Moderate coffee consumption is associated with various health benefits, including reduced risks of type 2 diabetes, liver disease, cardiovascular diseases, and cancer3. In a large cross-sectional study of 468,629 individuals without clinical cardiovascular disease, light-to-moderate coffee consumption was linked to lower rates of all-cause mortality, cardiovascular mortality, and stroke incidence4. Furthermore, coffee intake is consistently associated with a reduced risk of Parkinson’s disease in a dose-dependent manner, across multiple human cohorts5,6,7. Meta-analyses have also found that coffee consumers face a lower risk of depression8,9, and one meta-analysis of cohort studies examining cognitive decline, showed that coffee consumption accounted for a 27% reduction in the incidence of Alzheimer’s disease

It's like they're starting off with "Now don't get me wrong. Coffee will cure cancer, but..."

culi7• 3 months ago

Yeah it's telling how ISIC is covering this study. Their title is:

New research reveals mechanisms behind coffee’s positive effects on the gut-brain axis

https://www.coffeeandhealth.org/health/media-content/news-al...

carabiner• 3 months ago

Every damn time, for chocolate, coffee, and red wine "studies."

46493168• 3 months ago

Who else would fund a study?

TazeTSchnitzel2• 3 months ago

After habitually consuming caffeine (not in coffee form) daily, usually multiple times a day, for more than a decade, a horrible mental health incident happened to me that forced me to stop it for a while. Afterwards I didn't resume the habit, and so I no longer have a tolerance.

This has let me evaluate what caffeine does with fresh eyes, so to say, because I can now consume it occasionally while having many non-caffeinated days to compare to. It's a profoundly psychoactive substance and does a lot of things to cognition. I guess I have decided I don't enjoy how it feels, having previously been dependent on it.

readthenotes1• 3 months ago

Notably, the article is looking at coffee, both caffeinated and decaffeinated. There is a lot more to coffee than just caffeine...

mixedCase• 3 months ago

The overwhelming majority of the enjoyable coffee experiences are caffeinated. While there is good decaf out there it's not the norm, specially in smaller markets.

rimliu• 3 months ago

How do you know that caffeine was the cause?

ivan_gammel• 3 months ago

This of course cannot be generalized, but withdrawal is quite noticeable for personal well-being in a positive way.

TazeTSchnitzel2• 3 months ago

I didn't say it was the cause of the mental health incident! And I don't believe it to have been "the cause", either. It just happens to have been the thing that caused me to abruptly stop.

It likely was a contributor, insofar as the incident had poor sleep as a contributing factor, and I do know with some certainty the caffeine habit had been causing some (likely not all) of my sleep problems. I can also tell you the very worst day of that incident was when I mistakenly consumed caffeine again prior to being recovered enough for that to be safe; that was a horrible glimpse at what that drug can do to you when you're in an already very unstable state. Caffeine definitely can aggravate all kinds of symptoms, even when you're in a relatively stable state. It's a stimulant, after all.

But I think caffeine consumption is… only one factor of many in causes of that incident, and doesn't deserve any special blame. The relevance of the mental health incident here is really that it gave me a chance and a good reason to abruptly stop, and therefore also the opportunity to see what getting the brain back into the caffeination ritual again feels like. (I've tried taking it for a few consecutive days more than once since then, and not particularly enjoyed it. I've also tried it on single isolated days.)

barrenko2• 3 months ago

Coffee is a plant demon that created the western civilization as we know it today...

fermiNitambh• 3 months ago

I like this worldview. Prior to coffee, Europe was in the grip of the beer dwarves. Coffee demons took over and invented nationalism, capitalism and Keynesian economics.

1234letshaveatw• 3 months ago

colonizer fuel

BatteryMountain2• 3 months ago

I've had the same experience. Caffeine is super addicting, the ritual & habits surrounding it is a potent pull. For myself, it makes me erratic, impulsive, more reactive and agitated. One cup a day puts me on edge, makes me sweat more, makes me more intolerant, makes everything feel too slow. It such a sneaky drug and it can really get under your skin without you realizing how much it changes you.

orphea2• 3 months ago

I don't have the same experience, and I drink one cup of coffee (270 ml) almost every day. No agitation, no impulsiveness. I can drink coffee in late evening (let's say 8 pm) and sleep well. I guess I'm trying to say that we should not project our own experience on others, everyone is different.

apples_oranges• 3 months ago

Agree, I drink it a lot and then stop drinking it at least once a year for a few weeks, and for sure it's a different mode of mind, but can't really qualify it besides that I remember my thinking being softer, calmer and perhaps even "more correct" without coffee.

(But I never had any mental-health incidents, and I drink a lot of it, more than all people that I personally know.)

yetihehe2• 3 months ago

For many years I go to the same vacation spot (kayaking in the most beautiful nature place I have seen) and go cold-turkey. I didn't notice any side effects of lack of coffee besides slower muddier thinking. After I go back and start drinking coffee, feel back to normal.

I also had a very big life altering mental health incident very recently, drank A LOT of coffee during and I feel it helped, now I am much more calm, "more correct" despite drinking coffee like before.

Based on this I posit that coffee is used by humans to offset unwanted mentality changes, not a cause of unwanted mentality changes.

bayarearefugee2• 3 months ago

Quitting caffeine after decades of use was a bit of a mixed bag for me in the short term, but positive in the long term.

Going caffeine-free made it much easier to lose weight as I have far less cravings for high carbs and sugar now, presumably this is related to the impulsivity impact talked about in the paper.

Going caffeine-free also made me very depressed for a while with severe anhedonia, this lasted way longer (like 3-4 months) than one would generally expect for caffeine withdrawal symptoms.

I had seemingly become so used to the increased dopamine signaling while buzzed on caffeine that my brain was a mess for a rather extended period of time as it got used to not having it.

Overall I view quitting as a positive for me, but I'd warn anyone thinking about doing it to do it carefully and closely monitor their mental health. AFAIK the impacts of quitting can be quite different for different people, so my experience may differ than that of others, but I had no idea how much of a (temporary) mental health crash quitting caffeine could cause until I experienced it.

gabriel-uribe2• 3 months ago

I'm almost exactly 1 year coffee-free (not caffeine free, but significantly less because tea is much less addictive for me).

Also positive in the long-term for me. Fewer digestive issues, less spiky dopamine sensitive or impulsiveness and performance during the day, better memory. I wish it weren't so.

But damn was the 3-6 months of anhedonia awful. I still feel pangs of it.

fc417fc8024• 3 months ago

Going caffeine-free made it much easier to lose weight as I have far less cravings

That's surprising to me. In my case one of the reasons I discontinued it (emotional effects aside) was mild but consistent weight loss. The stimulant part of the effect seems to suppress my appetite quite effectively although at least part of that is likely indirect due to sustained task focus leading me to skip meals.

Noaidi2• 3 months ago

You may have naturally low dopamine production or release (or low ATP or GTP). Everyone will react differently because genetics so you are right, everyone needs to be mindful of their reaction.

You might want to look at this pathway, and the enzymes, and the cofactors for these enzymes:

https://www.researchgate.net/profile/Pingyuan-Gong/publicati...

Tyrosine 3-monooxygenase (TH) needs Iron

Aromatic-L-amino-acid decarboxylase (DDC) needs B6

randusername2• 3 months ago

I experienced a similar anhedonia when quitting caffeine. I don't think the caffeine itself was the problem, I think it was just helping a lot more than I knew with the inertia of circling the pit without tottering in.

Turns out I needed stimulants from time to time, just not that one.

Uptrenda• 3 months ago

I think this monthly withdrawal syndrome with the anhedonia reflects a true gap in scientific understanding of caffeine. There are communities where people routinely quit caffeine (e.g. /r/decaf) who all notice the same thing. Yet if you look at how long caffeine withdrawal lasts: the reference answer is 1 - 2 weeks (then everything is "normal.")

I think caffeine is legitimately more disruptive and addictive than is commonly acknowledged. It creates quite a life-style loop where you need it for [drive, energy, mood, alertness] as a fix to many of the issues it causes, lol. Caffeine is such a widely used drug yet doesn't seem to have been studied that much. It's fascinating to me how the drugs that are socially acceptable seem completely arbitrary. Like alcohol (which in terms of addictiveness isn't far behind the most addictive drugs.)

In tables that compare the most addictive drugs, you know what drug is always missing yet seems to be consumed more widely than any other recreational drug on the planet: caffeine. This is funny though. It may be difficult to actually do high quality, comparative research on caffeine because to do so you would need to find people who don't already consume caffeine and I suspect that is a harder problem than it sounds.

By the way: the set of people who have never been effected by caffeine shrinks even further if you consider whether the mother consumed it during pregnancy.

kakacik• 3 months ago

I do believe a lot of it boils down to tolerance. I for example feel basically 0 effects, and drink it just because I like the taste (of a good one with milk, or exceptionally some good espresso / ristretto after big dinner).

I recently traveled and didn't have coffee for more than a week. No change I could feel, no craving, nothing. But one of my ex-gf was quite sensitive on many things, had frequent headaches, low blood pressure and coffee was helping with those visibly. So YMMV.

yetihehe2• 3 months ago

After habitually consuming coffee daily in large quantities for two decades, I had mental health incident, during which I drank twice the amount of coffee and it felt like water. After that incident I still drink previous amount of coffee, but feel much better, much more rested, on an upward trajectory and like I have finally managed to escape the swamp I dragged myself into over many years.

After reevaluating your comment and my experience I declare that coffee is not always a cause of mental health incidents, sometimes it might help people.

Noaidi2• 3 months ago

Yes, same here. I have schizoaffective disorder and realizing that caffeine affected my mental health so drastically was the beginning of my recovery journey 30 years ago. I can use caffeine now as a drug when I need it. Same with alcohol.

amelius• 3 months ago

This happened to me with Pepsi cola.

But then I found out I can drink coffee just fine, even 5 cups per day.

Now I'm thinking it was the artificial sweetener.

testing22321• 3 months ago

Same. I didn’t realize I’d been living life through a fog until fully 12 months with zero caffeine

blopp99• 3 months ago

I had a similiar case with influeza the past december. I didn't eat for 4 days, fever for a long time, and low energy during the whole 4 weeks it took me to get back to normal.

I couldn't drink coffee or alcohol during those 4 weeks, and notice that I didn't get any migraines after those 4 weeks even when I, for the past 12 years, knew exactly how I got them reliably.

I didn't make sense to me to keep drinking coffee because the benefits of coffee which for me was mostly ritual and taste, didn't outweight the weight of having a migraine for sure if I slept a minute less than 8hrs.

Mind you, I'm talking about a cup almost everyday with milk, ice coffee in the mornings.

bichiliad2• 3 months ago

I had wild food poisoning and had a similar experience (took me out for weeks, didn’t drink coffee). I assume the body must have some sort of gating mechanism for pain; I have absolutely had caffeine withdrawal before, but not that time. I’ve since cut back and switched to tea, which I believe has helped with my anxiety.

grvdrm• 3 months ago

Can you speak more to the psychoactive and cognition impacts to you in specifics?

Very interested.

I am a regular coffee drinker, mostly limited to very early morning (e.g. 5-7 am). Also consume celsius here and there when I want to minimize stomach disruption in the morning (e.g. I am about to run).

But have also used THC in the past (no longer, major anxiety inducer for me). Alcohol like so many people. And more recently went on an assisted MDMA/ketamine therapy journey that continues to amaze me in its impact (in all good ways).

Asking as I am reducing caffeine slowly right now and curious what folks are seeing as differences on/off in real terms.

wafflemaker3• 3 months ago

I had heart/chest pains from Lisdextroamphetamine (ADHD meds) that went away when I stopped drinking coffee. And I drunk very little, just one half cup in the morning.

Much less anxious now too, but that's more likely due to ADHD meds.

Lalabadie2• 3 months ago

I've been a decaf drinker for close to a decade now, maybe my experience is interesting to you:

I have better mood, presence of mind and working memory in the morning, especially compared to caffeinated peers. I'm also a lot more aware of when I've woken up from a bad night's sleep (see paragraph 5).

I have much less mid-day dysregulation/impulses compared to caffeinated peers. No predictable afternoon slump either – but a rich lunch will always leave me foggy, lol. If it's the weekend, I'll often join my young kid for the afternoon nap and fall asleep in minutes – the 30-45 min nap usually feels amazing.

Coffee really feels to me now like the psychoactive substance it is. I've had anxiety issues for other reasons in recent years, and today a cup of caffeinated coffee will often trigger a good level of anxiety if I'm not physically active during the peak. The physical symptoms of both are very similar. If I'm moving about, it usually feels good, like something hyped me up, but the sensation comes on its own instead.

Anxiety greatly changes my sleep needs, and caffeine and alcohol both hid these sensations in the past, enough that I suspect I didn't have the interoception (https://en.wikipedia.org/wiki/Interoception) to consciously notice and adjust in the past, which would leave me stuck or spiraling in terms of maintenance/recovery, probably for weeks at a time.

In recent days (pretty low anxiety! knock on wood) I have sleep that's almost 2hrs shorter per night, waking up naturally. That came very progressively (sleep quality), then very suddenly (lower needs). Also a great gain, though I also aged a decade and that must contribute as well.

Note that I faded out caffeine by progressively substituting for decaf. No headaches this way (from a peak of ~4 cups a day, I would say?). It sounds like you're doing the same, which I really recommend! There's no need to self-flagellate on top of what's usually a major habit adjustment.

jayd163• 3 months ago

The occasional cup where you can actively feel you don't like it, doesn't sound like a solid analogue to the steady state of daily consumption.

I jog every day and enjoy vs I don't exercise but I occasionally sprint and I feel awful after.

IAmBroom6• 3 months ago

GP said they previously had daily consumption.

m463• 3 months ago

true coffee lovers drink decaf. (they can drink coffee often without or with fewer side effects)

iberator• 3 months ago

caffeine is not the same as coffee.

coffee is caffeine plus THOUSANDS of compounds interacting with each other and your body: some of them are protective for the heart for example.

That's why synthetic caffeine is bad, while coffee is overall good in moderation.

That's why more people die from energy drinks than from coffe in coffeeshop hehe

ANarrativeApe• 3 months ago

It would have been interesting to see if there was any difference relating to CYP1A2 (Cytochrome P450 1A2), the fast metabolizers and the slow metabolizers.

sdevonoes• 3 months ago

I must be weird, but coffee (or caffeine) doesn’t really “wake me up” in the mornings and I could drink it in the night and still sleep well. Because of that I don’t drink coffee; I prefer tea

fedeb956• 3 months ago

tea also has caffeine, although in smaller quantities. Maybe you mean that you don't care so you go by taste, just specifying because there's a common misconception about tea not having caffeine.

Lionga2• 3 months ago

Some tea has caffeine, most has don't.

vjerancrnjak• 3 months ago

I think this description is often associated with ADHD memes.

Falling asleep after a can of energy drink.

mrguyorama• 3 months ago

https://en.wikipedia.org/wiki/Paradoxical_reaction#Caffeine

This absolutely happens to my father, who uses coffee as a sleep aid but the science is sketchy.

It is documented but I don't know if it is scientifically valid

https://en.wikipedia.org/wiki/Attention_deficit_hyperactivit...

I can't find it now but I once read that people who report the "paradoxical reaction" to stimulants have a significantly better outcome from stimulant medications, and both those values seem to have higher heritability than ADHD as a whole, possibly even linked to a single gene.

opan• 3 months ago

I find that the effects can be pretty subtle, and if I'm already tired there's usually no coming back. What I think has worked best for me is to re-up on caffeine a few hours before I think I'll be tired, or around when a previous dose is wearing off. Also, if trying to stay awake, food and entertainment are also quite important. If I hit a point where I'm hungry, cold, and tired, and going to the kitchen to eat sounds like a chore, it's usually too late for me. When the bed's closer, it's hard to resist.

I've also noticed that I have a sort of natural energy in the morning. I think of it as being similar to how a seed has enough energy in itself to sprout and then get sunlight. It's probably so I can make myself eat and whatnot. I don't really need caffeine to "wake up" as much as I need it to stay awake later in the day, and even if I do have a coffee with breakfast, I'll often get tired before the normal day is over.

ziml772• 3 months ago

I also don't find that caffeine wakes me up or keeps me alert. I used to have it a ton because I like the taste but then mostly stopped because I was having some anxiety issues and wanted to be sure caffeine wasn't a factor. Stopping it was zero problem at all for me, which doesn't align with what others say about stopping consumption. I don't know if my body's metabolism of it is super fast or if my brain is weird in some undiagnosed way that prevents the caffeine from working "correctly"

fedeb956• 3 months ago

thirty-one participants were moderate coffee-drinkers (CD, i.e., people that usually consume between 3 to 5 cups of coffee per day).

3-5 is moderate? To me, 3 is already high.

Also, sample size is pretty low and they're all Irish.

alexey-salmin• 3 months ago

I do 6-10 espresso cups per day, so 3-5 does sound very moderate.

MagicMoonlight• 3 months ago

That’s not normal. It’s like saying “I drink 6-10 beers a day so 3-5 is very moderate”

andor• 3 months ago

It depends on how much caffeine is in your cup. Rather than measuring the size of a cup, I would go by the amount of coffee, as in the weight of the beans, used to brew it. The actual amount of caffeine is not as easy to measure, and even for the same kind of beans, there is natural variation.

For a traditional Italian espresso, about 7g of coffee beans are extracted. For a third-wave double espresso, it's usually 18g or more.

In my opinion, 10x7g is a lot. 2x12g is more than enough for me.

p4bl02• 3 months ago

I agree. I'm deep into specialty coffee and I love making and drinking coffee a lot, but three cups is already higher than what I drink on a normal day. Also, most of the time when I go above this threshold, I drink decaf.

benhurmarcel3• 3 months ago

I wonder how many grams of coffee beans they consider are in 1 cup though.

midtake• 3 months ago

Are the Irish unique when it comes to metabolizing coffee?

IAmBroom6• 3 months ago

Local groups of people sometimes share genotype characteristics. Better studies use a broad spectrum of people - a less biased sample set.

So the answer to your question is: we can't know, from this study.

kristofferR4• 3 months ago

This study is Irish, so I think they likely use 170ml cups? That means a normal mug of ~500ml is 3 cups.

Perhaps they even use US coffee cup size, which is 118ml?

Honestly, using an unit of measurement that varies from 118ml to 250ml in a scientific paper brings the whole paper into question.

finghin• 3 months ago

I’m Irish.

A NORMAL mug of 500ml??? this is insanity to me

skrebbel• 3 months ago

a normal mug of ~500ml

woa where is half a liter of coffee a "normal" portion?

hootz• 3 months ago

Okay, you'll definitely have to explain the NORMAL mug of HALF A LITER!

ashirviskas• 3 months ago

Does it matter what size the cup is? Usually you get the same amount of coffee water + additional water/milk/whatever.

fc417fc8024• 3 months ago

The reactions to your comment got me curious enough to check. The mug I use for coffee and tea holds almost exactly 400 mL when comfortably full and I used to drink 2 of those per day (across 12 hours or so). Based on that, personally I'd consider ~800 mL of black coffee to be on the high end of moderate consumption.

SecretDreams3• 3 months ago

I drink a small cup in the morning (like 250 ml) and 1-2 Moka pot espressos (like one shot). This typically happens between 7-10am. No more coffee after that most of the time. I like to keep it in the morning routine with breakfast. Green tea and water in my afternoons.

Personally, I don't feel any kind of "drug like" effects from this routine. I wonder about the strength of coffee people are drinking and the effects of drinking throughout the day rather than just the morning.

Anecdotally, during grad school I drank more per serving and throughout the day, and I certainly felt quite different than my current routine.

Like most things, I think people need to find some moderation/balance.

pillefitz2• 3 months ago

It's less about the strength of coffee than about your metabolism. I used to be unaffected by caffeine, and now it takes a few sips in the morning to mess with my sleep in the evening - sth that started happening in my twenties I believe, possibly liver-related.

TacticalCoder• 3 months ago

3-5 is moderate? To me, 3 is already high.

I'd say 3 is still moderate and really common. 5 is getting on the high'ish side.

Several of us here drink more than that.

ziml772• 3 months ago

One early in the morning, one maybe a bit before lunch, and one in the afternoon. Doesn't seem too out there. And you probably approach 5 cups if you're normalizing the size of a cup and seeing that people generally get bigger cups than that (I'd imagine one large cup in the morning and another in the afternoon would easily put you at 5 for the purposes of the study)

jmhammond• 3 months ago

I drink “two cups a day.” But it’s like 24-30 ounces.

shinryuu• 3 months ago

Would be real interesting to see a similar study on tea.

therealdeal2020• 3 months ago

good thing I have claude to summarize this and quickly realized that sample size was small and nothing much new unless you are a microbiome researcher

reliablereason• 3 months ago

If the effect size is big small sample sizes does not matter as much as otherwise.

You really have to look at the power analysis and the sample size together.

Saying this as a general truth. I am not sure about the power of the method in this papper, i only read the abstract.

arnejenssen• 3 months ago

I am not a coffee drinker, but I met with a friend at a cafe who said he was going to get a cup of insect poison, referring to coffee :)

tootie• 3 months ago

Caffeine evolved to deter insects. Coffee, tea, chocolate and some other plants all evolved caffeine independently due to similar evolutionary pressure.

throwatdem123113• 3 months ago

Caffeine is an extremely potent drug.

It’s actually kind of crazy to think that a large portion of a country’s population could be “high” on it basically all of the time. And there is a huge industry in place for delivering said drug to as many people as possible by having it available on almost every street corner.

And that most people take a fairly non-chalant attitude to giving this drug to kids through sweet drinks that are primarily marketed to them as well.

The scale of it is kinda mind boggling to me.

Mind the nonsensical rant, I haven’t had my coffee yet this morning…

adammarples3• 3 months ago

This week as I tried to lower my coffee usage or stop altogether, I had dropped from 3 cups a day to 1. That one suddenly started to make me feel noticeably high, like a bump of cocaine in the morning. I realised that I craved it in the same way and it clicked for me - coffee is literally just a drug I like to take by myself and read the newspaper. It's no different. It's the first thing I think of in the morning because I'm addicted. Currently trying to go cold turkey.

throwatdem123113• 3 months ago

I went from 60oz per day to 36oz. I went from perpetually stimulated to basically on stimulated during work hours. Even with a minor cutback, I’ve noticed the change in potency of an individual dose as well.

My next goal is to cut back to one fully caffeinated drink in the moring and then doing decaf the rest of the day.

The ritualistic habit is the hardest thing to break for me. Also the social aspect of “let’s go for coffee” with friends, family, spouse etc…

FireFjord• 3 months ago

How’s the cold turkey going so far?

Earw0rm• 3 months ago

That's normalising clean-ness (i.e. the state of being free of all psychoactive chemicals) perhaps too much.

The original humans adapted to a wide range of diets across the world (one reason why we're such a successful species), but most groups seem to consume mild psychoactives a lot (it's hard not to, so many wild plants have some level of activity) and seek out more powerful ones occasionally and for specific situations.

FrustratedMonky• 3 months ago

There is another huge industry to produce and deliver a pile of white powder to as many people as possible. Sugar. Highly refined, pure, hmmmm.

throwatdem123113• 3 months ago

Yup. Refined sugar probably is more dangerous to humans than caffeine even. Caffeine, to me at least, seems much less destructive in moderate long term use than sugar.

2OEH8eoCRo0• 3 months ago

The coffee provided was consumed with a quantity of hot water, milk, sugar chosen by the participant.

Could it be the sugar?

rubslopes• 3 months ago

Was this thread invaded by AI? Casually reading the first comments, 3 different users mentioned they had a recent "mental health incident" related to caffeine??

Search this page for "mental health incident"

fc417fc8024• 3 months ago

That doesn't seem even remotely surprising to me. Much of the readership here likely consumes inadvisable quantities of caffeine nearly every day and one of the most common side effects is anxiety followed closely by a number of other emotional perturbations.

proggy• 3 months ago

Possibly AI, possibly younger folks (18-24). “Mental health incident” is only one step removed from algospeak like “unalived”, “seggs”, and “neurospicy”. A detached, memetic phrase that has been implanted into the lexicon by a toxic brew of algorithmic social media moderation and heavy exposure to LLM conversational patterns.

IAmBroom6• 3 months ago

Or maybe just because language patterns change over time. You need to be hep to the new jive, daddy-o.

neuroelectron• 3 months ago

I only use caffeine or caffeinated beverages such as coffee at the most three times a week. And that's a heavy week for me.

homeonthemtn• 3 months ago

Yes, well, nevertheless. Sip

dgllghr• 3 months ago

I switched from caffeine (coffee) to theacrine (pills) and I like it so much more. I feel alert and focused without added anxiety. It doesn’t seem to affect my sleep at all. I really didn’t like how hard it was to quit coffee.

I don’t like that it’s a pill. I tried making my own theacrine drinks, but theacrine is so bitter that I never found one that I liked. I am still haunted by the chicory + theacrine drink I made…

Projectiboga• 3 months ago

Here is a fun citation with a brief summary. They suggest regular caffine use lowers your baseline and it just returns you to where you'd be if you weren't dependent.

University of Bristol. "Coffee consumption unrelated to alertness: Stimulating effects may be illusion, study finds." ScienceDaily. ScienceDaily, 3 June 2010. <www.sciencedaily.com/releases/2010/06/100602211940.htm>.

lanstin• 3 months ago

It allows you to rearrange your alertness budget in time if not in total.

culi7• 3 months ago

It allows the human to form a more effective cog

hpeinar• 3 months ago

A very interesting article, I have personal experience with:

Coffee also affects the gastrointestinal tract. It increases stomach acidity and stimulates the release of hormones that aid digestion. Both caffeinated and decaffeinated coffee promote the contractility of ileal and colonic smooth muscle, helping prevent constipation

As the two times in my adult life I've tried to make an intended break from coffee, it has ended up with almost unbearable stomach pain caused by constipation.

It's good to know that this is not linked to caffeine as I thought, so I will try un-caffinated coffee instead now because I tend to think that my general "tiredness" comes from actual caffeine.

irthomasthomas• 3 months ago

Can you actually get caffeine free coffee? I thought most decaf brands where only about 50% less.

hrldcpr• 3 months ago

You're right that the caffeine isn't entirely removed, but it's supposedly more than 90% removed.

(I'm even seeing the number 97% mentioned a lot online.)

trillic• 3 months ago

I've found hot water has the same laxative effect as coffee in the form of herbal tea.

Same ritual each morning without the unknown dosing of a stimulant drug.

LogicFailsMe• 3 months ago

I once quit caffeine cold for 6 months: 2 weeks of pure hell then it was like I never craved it until life got real and stressful and I fell off the wagon. Today, I drink my espresso with a dot of lowfat milk now and life is currently too real and stressful to consider trying to drop it again. I do suspect some of us likely have undiagnosed low-level mood disorders leaving us highly functional but discontent and caffeine is the spackling compound used to plug the hole in our souls.

CoffeeOnWrite• 3 months ago

When work was chill I went to decaf for the morning espresso on weekdays, and enjoyed real coffee on weekends. I took glee in withholding energy from work that I redirected to my personal time.

Then when work picked up, I went back to regular coffee everyday.

I don’t think there’s a hole in my soul though. And caffeine degrades my personality a little bit (to my own judgment).

smt88• 3 months ago

Caffeine (like all stimulants) can alleviate symptoms of various dopamine-related disorders, like ADHD. I'm sure many people are self-medicating.

z3c0• 3 months ago

This study considers caffeine concumption outside of coffee, so an alternative caffeine source might be worth looking into. That was my takeaway, at least. I also drink espresso, for the caffeine and the noticable ease on my gut compared to drip or pressed coffee.

BoneShard2• 3 months ago

I stopped drinking coffee for a month and didn't notice any difference in my anxiety/mood/etc, so I returned to my regular schedule (3-4 large cups in the mornings).

inerte• 3 months ago

Same here, and it made me wonder, why did I go back to drinking coffee?

My best explanation is that there are effects, I just suck at self-awareness :)

mjrpes• 3 months ago

I quit caffeine for a year but it didn't work out for me. I felt mentally sluggish all the time; there would be times I'd be staring at my screen with my mind resisting the act of processing any information. I also noticed I became very sensitive with how much sleep I got, and if it was anything less than 8 hours the day would be miserable. I could be a special case here with altered brain development since even as a small child I was drinking liters of black sun tea. So since my withdrawal experiment I've highly regulated my caffeine intake with pills with a maximum of 200mg a day before noon, although I will sometimes cut back to 50-100mg a day during periods when my life isn't running full steam. This has worked out well for me.

euroderf• 3 months ago

When I'd quit coffee in my 20s and 30s I'd get serious headaches. In my 60s, no headaches at all.

dghughes• 3 months ago

I never used to drink any caffeine. In fact the few times I had tried it when I was a teen or my 20s it made my chest pound my heart raced so much. It was Lebanese strong cardamom coffee so maybe not the best example.

Then at age 34 I started a new job my first shift work job, late evenings, some overnight jobs. I started off with fancy coffee like french vanilla. A year or so later the first Starbucks opened. I was drinking venti quad shot lattes.

Then energy drinks were permitted for sale here (we had a can ban for years). I recall after drinking a Rockstar 750ml for breakfast and the following muscle spasms made me consider I should tone it down.

So I've settled a bit a small coffee in the evening. Sometimes I don't even finish it.

nchmy9• 3 months ago

It's always amusing to read the self-narratives of a bunch of unacknowledged drug addicts when links like this get posted.

schnitzelstoat• 3 months ago

It has some genuine benefits though like for liver health, for example [1]. Alcohol does the opposite.

[1] https://britishlivertrust.org.uk/information-and-support/liv...

nchmy9• 3 months ago

There's a study that'll say pretty much anything. That's not my point though. Just that most people talking that get enthused about any of this are drug addicts who refuse to recognize it.

GuinansEyebrows• 3 months ago

unfortunately, it's never amusing to read the thinly-veiled self-narratives of the condescending when comments like this get posted.

culi7• 3 months ago

Read the very first paragraph of this paper:

Moderate coffee consumption is associated with various health benefits, including reduced risks of type 2 diabetes, liver disease, cardiovascular diseases, and cancer3. In a large cross-sectional study of 468,629 individuals without clinical cardiovascular disease, light-to-moderate coffee consumption was linked to lower rates of all-cause mortality, cardiovascular mortality, and stroke incidence4. Furthermore, coffee intake is consistently associated with a reduced risk of Parkinson’s disease in a dose-dependent manner, across multiple human cohorts5,6,7. Meta-analyses have also found that coffee consumers face a lower risk of depression8,9, and one meta-analysis of cohort studies examining cognitive decline, showed that coffee consumption accounted for a 27% reduction in the incidence of Alzheimer’s disease10.

nchmy9• 3 months ago

I don't see what relevance your comment has to mine...

sph6• 3 months ago

"To prove I wasn't addicted I stopped for a week. I felt depressed and tired. I'm back to my 3 cups of coffee a day as it cures my depression."

— every HN thread about coffee

subjectsigma• 3 months ago

We get it, you think you’re better than everyone else

nchmy9• 3 months ago

Nope. I'm also an addict, but aware of it rather than trying to "optimize my dosing"

mskogly• 3 months ago

We know, that’s why we do it.

username135• 3 months ago

If coffee was a god, I would pray to it.

codazoda• 3 months ago

This paper is not saying coffee is bad.

If anything, it leans slightly toward beneficial or neutral effects.

What broader science says (not just this paper).

Across many large studies, Coffee is associated with:

* ↓ Lowerisk of Type 2 Diabetes

* ↓ risk of Parkinson’s Disease

* ↓ overall mortality (yes, really)

Downsides (for some people):

* Anxiety / jitters

* Poor sleep

* Increased heart rate

maininformer• 3 months ago

Habitual anything intake shapes the microbiome, modifies physiology and cognition

beej71• 3 months ago

I drank a lot of coffee until I forgot to pack instant on a 3 day backpacking trip. Headache the whole time that I cured in 5 minutes by drinking a mt dew the minute we got back to civilization. Figured it wasn't worth it and weaned off.

Then it turned out my rate of getting migraines dropped off considerably. But I love coffee, so I tried decaf. Migraines returned to being more frequent. So that was that.

If I could get it without the side effects, I surely would. Right now I'm drinking a hot cup of delicious roasted barley tea. But it's not the same.

Nifty39292• 3 months ago

PSA: decaffeinated coffee contains about 1/3 as much caffeine as regular - so far from caffeine free.

mbil• 3 months ago

It depends of course but typically it’s more like 3% the caffeine of regular coffee

culi7• 3 months ago

That's not accurate. In an 8oz cup of decaf there's 2–15 mg of caffeine. Regular coffee is about 91 mg for an 8oz cup

silver911r• 3 months ago

Every study like this should clearly state who paid for it.

Institute for Scientific Information on Coffee

WesleyJohnson• 3 months ago

This discussion has been particularly insightful. I'm 47 and have been drinking 2 to 3 Mtn Dew Kickstarts a day for probably 10 years. I don't feel high, or jittery, or like I'm bouncing off walls. I have no trouble falling asleep, even drinking caffeine right up until bed time. But, I also have trouble focusing, am working with a psychologist on a possible ADHD (primarily inattentive) diagnosis, never dream, and am very forgetful.

Based on everything I'm reading below, and a "discussion" with Gemini, it's highly probable all of this is related. I know AI isn't a doctor, and confirmation bias and all of that, but even if it's all nonsense - backing off on caffeine or quitting entirely can only help.

So I'm going to star to day, by trying to not have any after 2pm. My regular bedtime is around midnight, so that's 10 hours. We'll see how it goes.

Thanks HN!

jcalvinowens• 3 months ago

I used to drink a small amount of blisteringly strong coffee in the morning and after lunch, but nowadays I drink a massive amount of relatively weak coffee throughout the entire day. Weaker than you'd ever get from a shop or in an office.

That's been a big win for me: I feel like I get to enjoy the coffee more, and it eliminated the negative effects for me.

I no longer feel like I suffer when I don't have it. I miss it, the way I miss the sunlight in my office on a cloudy morning, but it's strictly a positive for me when it's around. I only get headaches if I go from 100 to 0, even one day of reduced intake is enough to avoid it for me.

When I'm exhausted and going to bed, I'll go fill the coffee machine, and catch myself thinking "oh boy, it's going to feel so great to wake up at 6am and drink this". Then I shake my head at myself and laugh and how absurd that sounds :D

Coffee is above running hot water in my hierarchy of needs. Seriously. If I were forced to choose between coffee and alcohol for the rest of my life, I'd choose coffee in a heartbeat.

SummSolutions• 3 months ago

Congrats to this team, providing exceptional research on how coffee affects us physically and mentally. I think moderation is key.

deepsun• 3 months ago

What surprises me is how many people drink coffee first thing in the morning. The organism is literally in wake-up mode, with cortisol spiking ~30min after wake up. So you get a caffeine AND a spike in cortisol at the same time.

Better to wait at least couple of hours after waking up.

BrandoElFollito• 3 months ago

I am reading the comments and wonde about the spread of individual sensitivity.

I drink 3 to 6 Nespresso coffees daily, at various times, including shortly before going to bed. Sometimes I don't drink at all for a few days.

I don't feel any effects related to the number, or whether I drink it or not. Sure, this is subjective but when I compare myself to the stories of the commenters I start to wonder if there is any caffeine at all in what I drink.

haffi112• 3 months ago

I stopped drinking coffee for four or five years. I drank a lot before. You do realise that it has a strong psychoactive effect, at least it did for me.

I still don't drink coffee, but I started experimenting with paraxanthine and I absolutely love it (paraxanthine is the primary metabolite of caffeine and is also a stimulant). I feel like it gives me most of the benefit of caffeine with very few downsides (no jitters, no crash, exits your system faster).

Habitual coffee intake shapes the microbiome, modifies physiology and cognition

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