
The tantalizing links between gut microbes and the brain - etiam
http://www.nature.com/news/the-tantalizing-links-between-gut-microbes-and-the-brain-1.18557
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medymed
So many gut microbiome variables, so many neurologic variables in the brain,
so many type 1 errors calling out from the data in seductive whispers "publish
me...". While preliminary research is curious, I predict that more medium-term
progress will be a result of throwing fecal transplant at many disorders, it
will work for a few (like abx-resistant C diff), and it will not work for
others even though people will claim it does. and then people will make up
biologic stories about how things interact with decreasingly hand wavy
(inflammation!) theories that may or may not be practically testable depending
on the number of working parts involved. That's how medicine works a lot of
the time, anyways.

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giarc
There's not a single biological system in our bodies that isn't incredibly
complex and has many moving parts. How do you recommend researcher investigate
these interactions without being able to control for all these factors?

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medymed
Great question. I think this is why organ systems with (arguably) relatively
fewer interconnecting parts and more _accessible_ parts than the brain, for
example blood, are easier to research. Not all of the parts will be able to be
controlled, and the closest approximations are probably animal models with a
few cloned or inducible genetic changes where significant results are not
easily generalizable to people. Biology will probably not be like physics or
chemistry, where underlying principles are often generalizable to matter under
specified conditions, because we can't defineand control the initial context
within and around a human, and ethical guidelines ensure that studies are
limited to a morally acceptable degree. So we often have to see what
works/fails in practice and explain it in terms of what we know, try to fill
in the gaps with more research, and see where it takes us in terms of new
treatment possibilities. It's a very iterative ordeal.

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saneshark
The Mütter Museum in Philadelphia currently has Einstein's brain on display.
With all the controversy surrounding how his brain was stolen against the will
of Einstein and his heirs, it would be ironic if all one really needed to
recreate his genius was his fecal matter.

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cpncrunch
The thing is, we already know that the brain influences the gut, but this
doesn't seem to be mentioned. All these hand-wavy press releases seem to be
saying it's a mystery why IBS is linked to anxiety and depression, and yet
there is very good evidence that the HPA axis significantly influences gut
motility, absorption and bacteria.

As for gut-influencing-brain studies, they seem to be quite problematic. You
basically have a scientist looking at a mouse and saying "he's running around
a bit more than usual".

These studies get upvoted quite often here. It's almost as if people don't
want to take responsibility for their anxiety and depression...

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javert
> The thing is, we already know that the brain influences the gut, but this
> doesn't seem to be mentioned. All these hand-wavy press releases seem to be
> saying it's a mystery why IBS is linked to anxiety and depression, and yet
> there is very good evidence that the HPA axis significantly influences gut
> motility, absorption and bacteria.

Do you have a recommendation for further reading on this? (Specifically, the
brain influincing the gut, not vice versa.)

Purely anecdotal: I have a lot of digestion problems, but it is starting to
look like I do better when I am able to maintain a non-depressed, non-anxious
state of mind over a period of weeks.

~~~
cpncrunch
>Do you have a recommendation for further reading on this? (Specifically, the
brain influincing the gut, not vice versa.)

Try:

[http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2982.2008....](http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2982.2008.01171.x/full)

[http://www.researchgate.net/publication/14603941_Stratakis_C...](http://www.researchgate.net/publication/14603941_Stratakis_CA_Chrousos_GP._Neuroendocrinology_and_pathophysiology_of_the_stress_system)

