Coffee appears to rewire the gut-brain connection | Hacker News Reader

Coffee appears to rewire the gut-brain connection

sciencedaily.com

19 pointsloh15 comments

Seems similar to last year's Coffee drinking habits may greatly impact makeup of gut biome (48 points, 24 comments) https://news.ycombinator.com/item?id=42251379

Last year's wasn't funded by Scientific Information on Coffee

This paper (open): https://www.nature.com/articles/s41467-026-71264-8

Paper from 2024 (open): https://www.nature.com/articles/s41564-024-01858-9

> Scientific Information on Coffee

That sounds hilarious. So I had to look. It's the ISIC: Institute for Scientific Information on Coffee, "compris[ing] five of the major European coffee companies: illycaffè, JDE Peet's, Lavazza, Paulig, and Tchibo."

https://www.coffeeandhealth.org/about-isic

But it's okay, because

> ISIC is dedicated to contributing and consolidating balanced scientific information on coffee consumption – providing a reference for professionals and authorities who address health and wellbeing. [---]

Though

> ISIC works with the European Coffee Federation as well as with national coffee associations in the following countries [---]

suggests they don't work with any tea or soda federations to compare the scentific effects of coffee to other beverages.

Main authors study neuroscience (Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland,) so I bet the results are real, but as you point out, they knew that before even starting.

Sure. I have stopped drinking coffee because it increases stress and anxiety for me. This is the opposite of what the scientists have found according to the article.

I have a feeling that everything about food and how people digest it are dependent on the person and any generalized articles like this are completely useless.

> coffee was gradually reintroduced without participants knowing whether they were drinking caffeinated or decaffeinated coffee. Half received decaf, while the others consumed regular coffee. Both groups reported improvements in mood, including lower levels of stress, depression, and impulsivity. These results suggest that coffee can enhance mood even without caffeine.

Or it just suggests people are creatures of habit and comforts :)

This. The first thing that came to my mind, as a 'coffee drinker plus' according to the authors' definition, is that the participants' mood must have been one of relief and mild elation when after a fortnight, which equals two weeks, or, more precisely, no less than four teen mornings and four teen lunch breaks and four teen afternoons and for teen nights with no coffee, at all, they were finally allowed to sip on something aromatic, hot and brown, with mildly acidic and bitter traces, caffeine or decaf be damned.

I indulge in coffee quite a bit too.

But the funding chain here is -

Major coffee companies illy | JDE Peet's | Lavazza | Paulig | Tchibo

↓

Institute for Scientific Information on Coffee (ISIC)

↓

UCC/APC Microbiome Ireland study

↓

UCC press release → ScienceDaily article

Comes the newest research focus with a decline in caffeine consumption (in the younger generation)? Is this part of a strategic move to reframe coffee as a general 'feel good' product instead of the efficiency connotation it has today?

There are many ways to make coffee, with various options for additions like milk (including plant-based milk) and sugar, as well as flavorings... Don't these have any effect at all?

> ..The findings, published in Nature Communications and supported by the Institute for Scientific Information on Coffee (ISIC)..

Hmm

> caffeine boosted focus and reduced anxiety

As someone who it taking a break from coffee because of pervasive anxiety, and I am surprised how zen-like I am even two days in (among the migraines and anhedonia), this sentence from the abstract is so utterly wrong I won’t even waste my time with the rest.

Like, do they even understand the pathways and receptors that caffeine affects? You can say anything you like about caffeine, other than it is an anxiolytic. (Don’t get me started with the ‘coffee calms me down because I have ADHD’ trope)

With coffee we’re in the phase we’ve gone through with red wine, where every day a new article claimed that a glass per day would cure a new illness and make you live 120 years.

Are you substituting any caffeine? I've been cycling through month-long periods exclusive to coffee, yerba mate, and non-caffeinated herbals. Sometimes others.

When I cycle back to coffee, I find myself reverting to a maladaptive redlining and recovery rhythm. I suspect this has carved a compulsion for the work-hard-party-hard glow so prevalent in my younger years.

This pattern doesn't hold at all, for me, with mate or oolongs.

so how come IBS-C has a problem with coffee then?

Because the IBS gut biome needs more than just mood enhancement/comfort/lessened stress and anxiety?

Also from what I can tell in my skimming the study mostly focused on small (decaf) amounts of caffeine in the gut biome. There are still more components of coffee such as bitter compounds that presumably have other effects.

My assumption was the bitter compounds would be flavenoids but it seems this is not true. I'd say bitterness isn't of itself material to IBS its an effect higher in the gut tract. Gall for instance is very bitter and acrid, but necessary for digestion.

What is material is that coffee has a lot of interesting components beside caffeine.

However, I believe my rapid fight/flight gut emptying impulse after a cup probably is the caffeine.

(I have disregulated gut, my gut man (who said the disposable sigmoidoscope revolutionised his speciality) said I was just shy of IBS)

You can test if it is caffeine for you by trying sodas, chocolate, teas, and even caffeine pills.

At least in my own anecdata of IBS, caffeine alone does not have a laxative-like effect for me. I have noticed some but not all strongly bitter foods do, and heard a theory once that some flavoring compound that tastes bitter may be subtly enough like gall passes through the stomach to confuse the gut into thinking there may be a gall leak and to flush the system faster. That certainly sounds right to my anecdata, but also part of why I think I crave bitter foods sometimes (as an IBS-C to IBS-D switch/trigger).

Reply on news.ycombinator.com