Posted on 04/30/2026 9:45:34 PM PDT by Red Badger
New research led by University College Cork scientists suggests that both caffeinated and decaf coffee reshape the gut microbiome in ways tied to lower stress and improved psychological well-being, offering clues to the drink’s long-suspected health effects.
Coffee is a plant-derived beverage produced from processed coffee beans, with its flavor and chemical profile shaped by factors such as bean variety, ripeness, processing techniques, roasting, and brewing methods.
It contains a range of bioactive compounds, including alkaloids like caffeine, polyphenols such as phenolic acids, diterpenes, and melanoidins formed during roasting.
Moderate coffee consumption has been linked to a lower risk of several chronic conditions, including type 2 diabetes, liver disease, cardiovascular disorders, and certain cancers.
In addition, higher intake has been consistently linked to a lower risk of Parkinson’s disease in a dose-dependent manner.
Coffee drinkers are less likely to develop depression, while one analysis found that regular consumption was associated with a 27% lower incidence of Alzheimer’s disease.
In a new study, University College Cork’s Professor John Cryan and his colleagues explored the effects of coffee consumption, withdrawal, and reintroduction on cognition, mood, and behavior in the context of the microbiota-gut-brain — the bidirectional communication between the gut microbiome and the brain.
The researchers studied 31 coffee drinkers and 31 non-coffee drinkers through a series of psychological tests, caffeine and food diaries, and stool and urine samples to understand changes in their microbiome and perceived mood or stress.
Coffee drinkers were set as those who regularly consume 3-5 cups of coffee a day — defined by the European Food Safety Authority (EFSA) as a safe and moderate amount for most people.
Participants first abstained from coffee for two-weeks, with regular psychological assessments, as well as stool and urine samples throughout.
This period of abstinence for coffee-drinkers corresponded with significant changes in metabolite profiles in the gut microbiome, compared to non-coffee drinkers.
Coffee was reintroduced to regular drinkers on a blinded basis, with half of participants consuming decaffeinated coffee and the other half caffeinated coffee.
Both groups reported lower perceived stress, depression and impulsivity scores, suggesting that drinking coffee significantly improved mood, regardless of caffeine content.
Bacterial species such as Eggertella sp. or Cryptobacterium curtum were notably increased in coffee-drinkers compared to non-coffee drinkers.
The former is thought to contribute to gastric and intestinal acid secretion, while the latter is thought to be involved in bile acid synthesis — both of which may play a role in eliminating unhealthy gut bacteria and stomach infections.
Increased Firmicutes bacteria were also observed, which has been associated with positive emotions in females.
A notable improvement in learning and memory was found only in those who consumed decaffeinated coffee, suggesting that components other than caffeine, such as polyphenols, are responsible for these cognitive benefits.
However, the scientists found that only caffeinated coffee was associated with reduced feelings of anxiety, as well as improved vigilance and attention. Caffeine was also linked to a reduced risk of inflammation.
“Public interest in gut health has risen hugely,” Professor Cryan said.
“The relationship between digestive and mental health is also increasingly being better understood, but the mechanisms behind coffee’s effects on this gut-brain axis have remained unclear.”
“Our findings reveal the microbiome and neurological responses to coffee, as well as their potential long-term benefits for a healthier microbiome.”
“Coffee may modify what microbes do collectively, and what metabolites they use.”
“As the public continues to think about dietary changes for the right digestive balance, coffee has the potential to also be harnessed as a further intervention as part of a healthy balanced diet.”
“Coffee is more than just caffeine — it’s a complex dietary factor that interacts with our gut microbes, our metabolism, and even our emotional well-being.”
“Our findings suggest that coffee, whether caffeinated or decaffeinated, can influence health in distinct but complementary ways.”
The team’s findings appear today in the journal Nature Communications.
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S. Boscaini et al. 2026. Habitual coffee intake shapes the gut microbiome and modifies host physiology and cognition. Nat Commun 17, 3439; doi: 10.1038/s41467-026-71264-8
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“New research led by University College Cork scientists suggests that both caffeinated and decaf coffee reshape the gut microbiome in ways tied to lower stress and improved psychological well-being, offering clues to the drink’s long-suspected health effects.” Carry on the Dr. said.
Both caffeinated and decaf coffee have caffeine in them. There are coffees that are virtually 100% caffeine-free (99.9%+) and zero-caffeine coffee alternatives. The alternatives include beverages like Kaffree Roma which is a coffee sub that tastes a little like coffee but is not made with it, and Teeccino, same moniker. There are also fake teas like Rooibos Tea.
Prolonged, excessive coffee drinking (typically >4 cups/day) can lead to chronic anxiety, insomnia, increased heart rate, and elevated blood pressure. While moderate consumption is generally safe, long-term overconsumption can cause gastrointestinal issues like acid reflux, dependency, and potential bone density reduction, while paradoxically providing mental alertness. They don’t tell those that increase their consumption to get smarter about that.
wy69
Ok! Last week, coffee was dangerous. This week, it’s good for us. I’m getting dizzy, going back and forth.
>> I’m getting dizzy, going back and forth.
You should have another cup of coffee. You’ll feel better.
>> coffee reshape[s] the gut microbiome in ways tied to lower stress and improved psychological well-being...
Well sign me up! LORD knows my gut microbiome needs reshaping... I mean, just look at me, standing there on the scales...
...............”notable improvement in learning and memory was found only in those who consumed decaffeinated coffee, suggesting that components other than caffeine, such as polyphenols, are responsible for these cognitive benefits.”
Isn’t that special. +$!$@*^)$. I drink half-caffeine every morning (half-caf. ) so apparently I can’t tell whether I’m coming o going. Plus, I don’t brew, I use organic instant coffee, supposedly far stronger.
😂
Have a cup of coffee and think about it..............
I drink tea. Coffee upsets my stomach. No issues with dementia or memory. Age 86. I never miss daily aerobic exercise. 3 days of the week I am at local YMCA doing Zumba dance class for 45 min each. Other 4 days of the week it is either treadmill or beach walk for 30 min.
Tea is good, too. It has caffeine, just not as much..............
I have known this for 50 years.
Black Coffee
Black coffee is my name
Black coffee is not a thing
Black coffee, freshly ground and fully packed
Hot black coffee, boys, mmm that’s where it’s at, mean it
Way back you all know since I don’t know when
See I got hungover before I was 10
You see my skin is white but my soul is black
So hot black coffee, that’s where it’s at
That’s what I’m talkin’ about boys
(Black coffee) That’s what I mean
(Black coffee) Ooh you’ve got to feel it in your hand
(Black coffee) Hmm yeah
(Black coffee)
Well you hear that
Some black tea, well it can’t compare with me
Black tea (can’t compare with me) that’s right
Black tea, well it’s as good as, it’s as good as, it’s as good as it can be
But it’s a cup of black coffee that a working man needs to see, yeah
In America, well it’s the land of the free
You can get what you want if you’ve got some do re me
Well travelling far and I work like a slave
Now I’m independent, and you know I get laid
I got me a job and I build me a place
I got a spit of black coffee, oh how good it tastes
I said a dime is all it costs in the States
For a cup of black coffee, how good it tastes
Alright
(Black coffee) Oh
(Black coffee) It’s what I want now, it’s what I need
(Black coffee) To suit my soul, to suit my soul now
(Black coffee) It’s what I want, it’s what I need
(Black coffee) It’s where it’s at, it’s where it’s at
(Black coffee) Oh
I’ll sleep better knowing this!
“...supposedly far stronger...”
If you mix that right, it could swim a river and still be coffee. But the gist of the article as I read it, was that if you get rid of your coffee intake, you’ll be smarter. You may be comatose all day, but smarter.
wy69
I’ll take this coffee study over the last one posted which was all negative... Guess I should read every other one.
I didn’t see anything in the article about coffee making you dumber. Also, some people don’t get insomnia from coffee. I sleep without a problem.
if you live long enough this happens with nearly everything. My opinion is, everything in moderation and listen to what your body wants.
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