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]
[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/1055415221. I stopped drinking heavily and using other drugs, i.e. marijuana
2. managed my diet to avoid heartburn without medication
3. schedule my meals so it was easier to sleep at night (always eat something for breakfast when I wake up)
I did not need any "poo infusion" or anything.
I had a gal bladder removal that didn't fix the problems the doctors thought it would and got a lot smarter about the kinds and variety of food I eat.
I believe alcohol in particular was really screwing up my gut biome and entire digestive system.
But I've been able to cut for months at a time. Whenever the cut happens, I feel my brain sort of "return" roughly a week or two in.
I'm not sure how to explain it other than something like fog clearing. Obviously makes some intuitive sense when you read it.
However, as someone that has consumed alcohol somewhat regularly (sometimes more, sometimes less) since college, it's bizarre to think about that consumption in retrospect. In effect, years and years of "fog" - it makes me wonder how different or similar life would have been without that fog.
Can't change the past now, but a data point and strong signal for the future.
Heavy alcohol use and marijuana are both known to impact memory and recall directly.
Discontinuing both of those explains changes in memory. Attributing this to microbiome changes does not follow.
The association between gut microbiota and cognitive decline: A systematic review of the literature
https://www.sciencedirect.com/science/article/pii/S027153172...
It shows ”Gut microbiota modulation improves cognition in adults with early impairment. Diet, probiotics, and fecal microbiota transplantation share mechanistic pathways and that evidence clarifies how microbiota-targeted strategies support cognitive health.”
The action could be explained due to an anti inflammatory action by the gut biome.
That paper commits one of the major sins of many microbiome papers which is to attribute all benefits of diet change to the microbiome. Like the parent commenter it gets drawn to the idea that all changes in the body can be traced back to the microbiome and assumes that it explains everything, but that’s obviously not true.
However, when someone is taking two powerful substances with direct brain action and known modulators effects on memory, blaming anything else in the body is bad logic.
And who said they don't do this (long term) exactly through their affecting the gut microbiome?
They do not exert their primary effects via microbiome modulation. This is obvious because the effects occur nearly immediately upon consumption, whereas microbiome change from what you consume is a gradual process.
The question I have is: Why has microbiome become the explanation for everything? What would lead you to believe that microbiome would be the explanation for this, when the direct action upon the brain is so much more direct and obvious? Microbiome is an interesting area of research but how did we get to this point where some are ignoring the obvious and trying to construct alternative microbiome based explanations for things like alcohol and marijuana impairing memory?
Which is orthogonal as to whether those direct actions also affect long term memory.
>They do not exert their primary effects via microbiome modulation.
Who said anything about primary effects?
Might the reason be that we're constantly finding new important ways it affects things, or that we see major changes to seemingly orthogonal issues from targetting the gut microbiome directly?
(less/no simple sugars, much more vegetables and starches/fibers, regularly eating 4 corn/20 plant oatmeal few times a week)
I had an infection and was prescribed antibiotics, and needed to pause the esomeprazole. I asked gemini about it and it suggested I take two probiotics while on the antibiotics, Saccharomyces boulardii and Lactobacillus rhamnosus GG. I noticed after a few days that I wasn't getting heartburn, and started putting the pieces together.
After the antibiotics ended, with still no heartburn, it recommend I add rhamnosus gg to the mix. So now I take all three daily and rarely get heartburn. It's been quiet a shock
Foods to eat, oatmeal, lentils.
Ginger tea, activated charcoal tabs.
Most all of that works very well to support gut bacteria so throwing some probiotics in as well can help. The gummy kind available in generic or Digestive Advantage work well!
I even once read that someone noticed an issue they tried to clear up for years with doctors went away on day 3 of a water fast. No, he wasn't going to fast forever. But he was shocked the first relief he ever had was that day. From there he solved his problem once his eyes were opened a bit.
I'd personally try all ground beef for a week or two. It won't kill you. Is it ideal? Probably not. But you will not have any problems from that short trial. Then add things slowly until you have a whole good diet you like.
Look into low-FODMAP diets if you haven't already.
For example
>I stopped drinking heavily and using other drugs, i.e. marijuana
Like the primary change you made was to cut out using a whole bunch of drugs with known, significant neurological effects.
Here's a study that tried fecal transplants to treat mental illness (and found no effect): https://pubmed.ncbi.nlm.nih.gov/41785480/
The pattern with this stuff is that, when a blinded study is carried out, there's usually no effect.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12536323/
It also found the effect was greater in people with IBS.
The positive result is heavily driven by an outlier study on Fibromyalgia that has results that look a little too suspicious relative to the other studies.
This is basic ecology, the bacterial population dynamics in your colon are a direct result of substrate availability. If it’s primarily fiber, polyphenols, and other indigestible plant compounds reaching the colon you’ll likely have a healthy microbiome. If instead you malabsorb food from poor lifestyle factors and have macronutrients reaching the colon they’ll probably fuel blooms of pathogens. I think microbiome researchers need to talk with ecologists more to help advance the field out of the myopia it’s in.
FMT does appear useful for special cases of infection like c-diff, but I think that’s led people to believe it’s a generally health promoting practice, when the research simply does not show it.
Sure, you have to put in a lot of effort to get the system starting, but eventually the feedback loop pays dividends that outweigh the principal.
Everything else about the human body seems to be this way, adaptation or maladaptation.
im talking about impacting your microbiome through another animal, not the short term effects from aerobic exercise or BDNF and what that feels like. this experience didnt hit quite like other typical metabolic functions.
great to hear you like BDNF. we all could use more of that.
Meanwhile, you suggest that such microbial influence must be reason you feel calm right after riding your horse.
I don't think I need to further explain why it's a ridiculous claim.
Exactly how negative it is though is difficult to determine and probably varies from person to person.
It must be the case that these microbes need the subject to be aware of their presence! Maybe the microbes have consciousness, and for the treatment to work, the microbes' consciousness has to entangle (via quantum mechanisms) with the subject's consciousness? Blind studies prevent this quantum entanglement to form, that's why the treatment stops working. We definitely need more research in this direction!
Also one issue with all of these studies is they only look at averages and don't do subgroup analysis. It may be that a few patients have an underlying condition causing depression that is highly responsive to these interventions, while it has no effect on the others.
One day people will figure out how to use these correctly.
Serotonin in the gut doesn’t go to your brain. It serves a different function in the gut.
The brain synthesizes serotonin inside of the brain. It doesn’t come from your gut.
I think the fecal transplants help to essentially seed your gut with healthy bacteria, which makes adapting to the proper diet easier when your body isn't constantly fighting you.
If you're interested in digging into the people that were doing this, they had a website dedicated to everyone telling their stories of how they went about their own individual journeys.
The website was called thepowerofpoop.com and looks like it's gone now, but is available on the wayback machine including individual articles and images.
I would go back to at least 2022 .. I think they possibly got in legal trouble at some point and started taking things down.
Microbiome transplant therapy is a domain full of grifters right now who will push it to vulnerable populations desperate for hope, like parents of autistic children. The real research results are much less promising for difficult conditions.
More recently, a study finds The modulation of the gut microbiota using MTT in ASD has shown beneficial and long-term effects on GI symptoms and core symptoms of autism[3]
[1] https://gutbrainaxistherapeutics.com/pipeline/#clinical-tria...
[2] https://link.springer.com/article/10.1186/s40168-016-0225-7
[3] https://www.tandfonline.com/doi/abs/10.1080/19490976.2025.24...
And nobody is bothered by the story. And it gets less clicks. People get cranky when they have been suckered.
This factoid is repeated everywhere but it’s misleading without knowing that gut serotonin is a different pool than brain serotonin and they have different functions.
The brain synthesizes its serotonin locally within the brain.
The fact that we both use Salesforce does not matter. It’s internal and doesn’t mean anything outside the company. Both the brain and gut re-used the molecule for their own internal signaling. Evolutionarily it was cheaper to use an existing molecule.
To the brain, the invoice is just “I’m full” or “I’m hangry.” It doesn’t care how much serotonin the gut had to produce internally to issue that “invoice.” The brain will produce its own serotonin from the signal of satiety but it won’t give you any more than you can from just feeling full.
It is like these armchair scientists don't understand that the actual scientists know the limits of the model system better than they do.
Science depends on accurately reporting facts, being clear about the limits of your findings, and seeking explanations that survive scrutiny. Science journalism has other priorities that are often in conflict with those of science.
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...
"You can cure anything in mice."
I don't know the mechanism why, but you can find tons of papers with incredibly strong results for curing of mitigating dementia, cognitive decline, addiction, etc in mice, but these almost never seen to work on people.
The other thing concerns how potent the effect is to be therapeutic. In many cases, the effect is just marginal to be meaningful.
Conceivably parenteral capsaicin has different effects on hippocampal integrity or physiology than achievable with ingestion. I'm not familiar enough with disposition of capsaicin in the gut to comment further. My question is whether capsaicin passes from gut into the circulation in any appreciable quantity. I suspect it doesn't but I couldn't say I know for sure. I'll have to add it to the already long list of things I need to look up.
There are countless papers published where simple ingredients produce miracles in mice. Most of them don’t replicate.
If you look up most food ingredients you can find someone, somewhere claiming to have used it to produce amazing outcomes in mice. After you read a lot of those you learn not to take individual papers seriously if the claims seem too good to be true.
Can't disagree, but keep in mind that almost all meds are tested first in mice/animal models before human trials verify the effects.
It’s about singular papers with too good to be true results. You can find these in humans too.
The rational mind should not be seeing singular papers and assuming they’re correct. There are a lot of incentives for researchers to publish amazing results that benefit their career. They find ways to publish these through small sample sizes, p-hacking, or worse like faking results.
The amazing results usually disappear in larger studies by more rigorous researchers. There are so many papers showing amazing things in a handful of mice in a lab or even human volunteers that do not appear again in properly powered studies.
I never said we have sufficient evidence to act. But "too good to be true" + "singular paper" together can become an unfalsifiable dismissal - by that logic, every important result looks suspicious before it replicates. The interesting question is what priors should update our confidence here.
Stanford/Arc Institute and published in Nature + mechanistic grounding + prior research on gut-brain axis gives me way more confidence than average, but you're right, that's not nearly enough for most, but quite sufficient for me, and surely others with informed priors or a strong motive.
Every important result should look suspicious before replication. This is the rational way to interpret early research.
You should not allow your mental probability distribution to be anchored around the first claim you see that is proposed as a paper. In the modern publishing environment, a heuristic of assuming singular results will not replicate would be accurate more often than assuming they’re true.
This isn’t intuitively obvious until you’ve read a lot of papers. It’s unfortunate but true.
Even some of the widely accepted findings like the benefits of fish oil supplementation are having a hard time replicating in large scale studies. Go back 10 years and it was almost universally accepted that those early fish oil studies must be true.
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.
type A cannot have been living in humans thousands of years ago, but type B might have
type A benefits from making your brain worse at choosing healthy foods, and type B does not
Which kind would you rather have in your gut?
How sure are we about this? How certain are we that those specific species of mold have a net negative effect, rather than a net positive (like for example mushrooms)? Penicillium grows on stale foods and I doubt eating it would have a net negative effect.
Feel free to eat it.
"Penicillium Species and Their Associated Mycotoxins" - https://pubmed.ncbi.nlm.nih.gov/27924532/
btw people, do drink water to keep up with the fiber. Otherwise it might not help.
Sure sounds like another fad diet.
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.
False. We do crave stuff. The microbiome contributes to and influences cravings, but the way you're phrasing it is misleading.
The fact that this doesn’t happen should give you pause about this woo-woo theory of cravings.
The reason you crave sugar and fat and other tasty things is that they taste good. You evolved in a world where feeling rewarded and driven to consume more of these was beneficial to survival when food was scarce.
Covered in my comment above: The more primary drive is that those are high calorie foods. A drive to consume more high calorie foods is beneficial in times of food scarcity, like the past.
It does some decimation, but not a full genocide.
Antibiotics are a far more powerful and faster modulator of gut biome, therefore if the above was true we’d see similar effects occurring more rapidly with antibiotics than diet.
The paper is open access. The discussion does a fine job of providing a full context for interpreting their findings.
"Why Isn't My Brain Working?"
by Datis Kharrazian
published in 2014 talked about this over a decade ago.
Edit: one of many examples: https://www.science.org/content/article/journal-retracts-inf...
I think for something this unexpected you'd want a much lower P.
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...
Through the vagus nerve and serotonin availability, a dysbiotic gut amplifies lower level threat and conservation signals, making them harder for higher level prefrontal predictions to outcompete. What feels like weakness of will may partly be the system running on a degraded substrate… the DMN then constructs a story about discipline and character over a causal chain that started in the enteric nervous system.
So, you can’t even really perceive some of this. But you essentially can’t overcome it either. The decisions are made before you thought about it.
I kid, ;) but I see your point. The idea that you might, say, struggle to resist candy and sweets and it's because some population of your gut biome is fighting for its life if you don't eat sugar... makes sense.
The idea that "I just cut sugar out for six weeks and my willpower to resist sugar went through the roof" ... not because your willpower changed, but because you killed that part of your gut biome.
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.
Anyone know what molecule and treated how?
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?.
#include <gpu_control.h> // g stands for gut
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.
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. "
The connection between gut-brain has been studied in humans, as well as the effect of diet and gut bacteria on brain functions.
> Importantly, vagus nerve stimulation is approved by the Food and Drug Administration as a treatment for depression or epilepsy and to aid stroke recovery.