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Comment by uLogMicheal | Hacker News Reader

Next will we find that there is an exchange of microbes between the brain and gut?

We can take it one step further: There are microbes everywhere in your body, they matter and they do things. When you take them away or fuck with them too much, weird things start happening.

It is I think not a particularly surprising take. But then often it can be valuable to have things that are kind of obvious codified into a paper of some sort so that we no longer have to rely on "but isn't that obvious?" and can instead point to some primary source that actually explains what is true. That way it can be true for everyone, even the people for whom it wasn't already obvious.

The most foundational science is pretty obvious after all.

We all know that apples fall from trees and that banging 2 rocks together makes sparks.

Not all rocks (at least using human strength)

It's obvious from apples falling from trees that gravity is actually the curvature of spacetime?

I think maybe “foundation” was the wrong word.

Maybe origins?

My point was that the basic ideas that have been studied and refined over centuries were simple.

Is there any evidence (yet?) of an autoimmune disease caused by the immune system accidentally attacking part of the micro-biome?

The immune systems does nothing by accident. The immune system is always trying to keep the microbiome in balance and the microbiome helps the immune system as well.

There is no winning, only balance.

Great question. Not that I have heard of.

Idk if there's evidence of it but I know many people claim they developed celiac disease after a course of black label antibiotics

Yes, as far as I know. I thought this was a nice overview: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6300652/

I’ve got a gut feeling that we will. A gut feeling in my brain.

Of course. Gut microbes to blood via leaky gut, small enough blood microbes to brain via BBB.

That’s the purpose of the BBB, which breaks down in hypoxia and cell death.

So-called " leaky gut" is hogwash pushed by quacks. It's what influencers push on TikTok or at least their interpretation of it.

https://www.mcgill.ca/oss/article/medical-critical-thinking/...

Sure, leaky gut as a diagnosis is a misapplication for the science. What is real is varying permeability of the intestinal lining in all humans.

Varying intestinal permeability has usually been related to inert compounds. More recently there has been some study on the significance of certain microbe metabolites, but the evidence for any kind of large scale microbial translocation in people that are not very sick (ie septic) is extremely tenuous.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10059777/

"Key controversies in blood microbiome research are the susceptibility of low-biomass samples to exogenous contamination and undetermined microbial viability from NGS-based microbial profiling"

Just because you can amplify some sporadic bacteria DNA from the blood does not mean that bacteria are hanging out in the blood in a physiologically meaningful way.

A lot of it is frankly junk science in disreputable journals.

On the otherhand: https://www.nature.com/articles/s41564-023-01350-w

"Despite this, we found no evidence for microbial co-occurrence relationships, core species or associations with host phenotypes."

"does not mean that bacteria are hanging out in the blood in a physiologically meaningful way."

That's the whole point of this sort of research - to find out if there are physiological connections and what they are.

They used to, but then they built the vagus nerve

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