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Enhancing gut-brain communication reversed cognitive decline in aging mice

371 pointsby mustaphahyesterday at 4:38 PM179 commentsview on HN

Comments

inanutshellusyesterday at 6:07 PM

Everyone's "poo-pooing" the article because the title doesn't mention mice, but, FWIW, stories of gut biota affecting humans behavior have been documented for a while.

Memory gain is noteworthy, which is the article's "wow" factor, but everyone's just knee-jerk smirking so ... here's a few random articles to gross you out about the wild world of trading microbiota and, for better or worse, changing your personality:

  * "My butt made me crave candy."[1]
  * "Gee, I'm not bipolar anymore thanks to my husband's butt juice infusion."[2]
Crazy, right?

   [1] https://www.psychologytoday.com/us/blog/the-behavioral-microbiome/202404/hacking-an-individuals-personality-through-their-gut-contents

   [2] https://www.abc.net.au/news/2025-07-28/faecal-microbiota-transplant-credited-with-curing-bipolar/105541522
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mustaphahyesterday at 6:47 PM

Yeah, it's a mouse study, but there are tons of human studies backing the whole gut-brain connection. There are even a bunch of books on it [1][2].

What's really cool is that the paper used low-dose capsaicin (just 5 μg/kg injected), and it completely restored hippocampal FOS activity and memory in older mice. Basically, that's the same stuff you get in cayenne pepper supplements - pretty easy to get your hands on.

[1] https://www.goodreads.com/book/show/28837738-the-mind-gut-co...

[2] https://www.goodreads.com/book/show/35210457-the-psychobioti...

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iammjmtoday at 11:55 AM

I believe there is a lot of shame-induced ignorance around this whole subject. Culturally poopin' is in the similar category like sex or death, outlawed from most "civilized" debates. But consider how central digestion is to our existence: basically almost before everything else we must consume -> digest -> expel first. You are not getting that smart brain of yours without that poopy butthole to go along with it

seethishatyesterday at 6:47 PM

IMO people should eat more fiber. A lot more fiber. It cleans the gut, the liver, absorbs cholesterol, slows insulin response and makes you feel full longer. The microbes in our guts need it to function.

Rather than jumping from one fad diet to another, just eat what you like and be sure to get a lot of fiber each day.

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robwwilliamstoday at 3:13 AM

Very well done study with a cautious interpretation of potential translational relevance in humans.

The paper is open access. The discussion does a fine job of providing a full context for interpreting their findings.

https://www.nature.com/articles/s41586-026-10191-6

theshrike79yesterday at 9:28 PM

"You" don't crave stuff, the microbiome in your intestine craves stuff.

There are microbes in there that specialize in eating, say, sugar. You don't give them sugar, they send signals to your brain saying "yo, more sugar"

This is why if you go on a sugar-free diet (just stop eating candy and sweets) the cravings just go away eventually. The microbes who keep shouting for more sugar either die away or go dormant.

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youknownothingtoday at 2:47 PM

Unless I misread, I found interesting that exposing young mice to old-mice bacteria makes them behave old, but exposing old mice to young-mice bacteria doesn't make them behave young. I wonder if there is something in old-specimen bacteria that wins over young-specimen bacteria.

dharmatechyesterday at 7:41 PM

The book

"Why Isn't My Brain Working?"

by Datis Kharrazian

published in 2014 talked about this over a decade ago.

maxall4yesterday at 5:52 PM

I smell bad data. This sounds too good to be true and most studies of this kind have turned out to be false a few years down the line.

Edit: one of many examples: https://www.science.org/content/article/journal-retracts-inf...

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riazrizviyesterday at 7:26 PM

Great info. This is one of those things that it is much faster for an individual to take into their own hands to prove out, rather than waiting for the system to provide us with an answer. Too many decision makers who are unlikely to all be aligned with our own individual interests.

hi_hiyesterday at 8:00 PM

For those who may be interested in learning more about the gut and how it affects your body and brain, this is a great, accessible, read

https://www.amazon.com/Gut-inside-story-bodys-under-rated/dp...

Also, while we're on the topic, if you ever find your self at the other end of the world in Tasmania, I highly recommend a visit to the MONA museum, which houses the Poo Machine.

https://www.abc.net.au/news/2017-11-07/mona-poo-machine-join...

kseniamorphyesterday at 8:25 PM

i like how this research (and others related) kind of supports the idea that free will might be lacking. I still keep a pinch of skepticism about this idea, understanding that it's just a concept. But personally i like it, because it even fells a bit relieving... not to say that it helps you abandon responsibility, but it makes your stance on life easier, and pushes you not to blame yourself too much for your weaknesses.

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m463today at 2:38 AM

unrelated but maybe interesting...

I had a colonoscopy and had to empty my system.

I had 1/2 gallon of this fluid to drink the night before, and the other 1/2 gallon to drink the day of. At that point my digestive system was empty.

I will say with an empty system I felt energized and a lot more clearheaded.

I wonder if doing this from time to time is helpful to your system, and furthermore if eating smaller portions would be helpful to my energy levels.

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nothrowawaysyesterday at 7:38 PM

> They showed that colonizing the guts of young mice with this bacterial species inhibited their performance on the object recognition and maze escape tasks, and that this deficit correlated with a reduction of activity in the hippocampus.

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gcanyontoday at 12:30 AM

>they treated old mice with a molecule that activates the vagus nerve

Anyone know what molecule and treated how?

sn0ntoday at 6:52 AM

Yogurt and pickled things acquired.

SilentM68today at 7:17 AM

That makes sense. I am of the opinion that the gut-brain connection exists. It is real in my view. A healthy gut promotes better mood and health. A parasite-ridden gut leads to all sorts of issues, including anxiety, irritability, stress, constipation and its counterpart, cancer and mental decline. I am doing a gut cleanse now to rebalance my intestinal flora and hopefully remove any bad actors from my gut resulting from years of ingesting processed foods. Want to make sure no parasites accompany me on my upcoming medical imaging visit.

FrustratedMonkytoday at 12:01 PM

Article doesn't mention any particular foods that would help.

Is it the typical, eat more fiber, more non-processed, Mediterranean? And this is just showing yet another thing that diet impacts? A link exists, but no specific types of diet to help with aging?.

lsc4719today at 3:18 AM

You are what you eat.

theletterftoday at 7:47 AM

Now I only need to find out how to use the 387 gut coprocessor in my belly to crunch those floats.

#include <gpu_control.h> // g stands for gut

renecitotoday at 1:57 AM

incoming GPL4

Frickenyesterday at 8:50 PM

I got into bicycle touring a few years ago, and it’s an ultra-endurance activity which means burning 3- 4 times as many calories as I would on a sedentary day. My training rides were all local weekend overnighters in preparation for the big 1000 mile challenge ride, and they were no big deal.

On the big ride, about 3 days in I started experiencing bouts of intestinal distress which would put me into some of the blackest moods I can recall experiencing as an adult. My whole thought process broke down and I became ruthlessly nihilistic about everything. I was ready to tell my partner to go fuck himself, chuck my bike off a bridge and take an uber to the nearest airport.

But then when the intestinal distress subsided I came back to my senses and I was like “WTH was that all about?” It happened several times, to varying degrees of intensity over the 10 day tour. My eating strategy improved and I bought some cannabis which helped my manage the issue and I was able to complete the tour.

That was a few years ago and I’ve never experienced the black mood again. It has prompted me to believe that the mind-gut connection is much stronger than we might have been giving it credit for, and if you suffer from mood or cognition issues, big or small, you may want to investigate whether your guts and gut flora might be playing an influential role.

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fnord77yesterday at 5:41 PM

... in mice. So if any of this held in humans, I think you'd see reversal of old-age memory problems in people treated with antibiotics that kill Parabacteroides goldsteinii.

As far as I know, no such effect has been observed.

And this article claims inflamation from that strain, the NIH claims otherwise: "Parabacteroides goldsteinii is a next-generation probiotic gut bacterium with significant anti-inflammatory and metabolic benefits, often reduced in obese or diseased states. "

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builderhq_iotoday at 8:30 AM

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steve1977yesterday at 5:42 PM

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behehebdyesterday at 8:34 PM

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rubyrfranklin2today at 1:05 AM

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ArchieScriveneryesterday at 10:34 PM

So drinking turpentine will cure my homosexuality?

theususyesterday at 5:52 PM

Mice mice mice. Tell me when you test on humans

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