
The body’s microbial community may influence the brain and behavior - bookofjoe
https://www.nytimes.com/2019/01/28/health/microbiome-brain-behavior-dementia.html
======
1024core
I grew up in India. I remember elder folks in my family talking about how the
"water" of a place made people different. And that if you moved to that place,
slowly you'd become like them too. They attributed certain characteristics
(aggressiveness, smartness, etc.) to the "water" of a place.

Now, of course, this had no scientific basis. But it would be interesting if
what they thought was the "water", was actually the microbial composition of
the traditional water sources there.

~~~
fxfan
"of course this has no scientific basis"

You probably mean- I haven't seen any research that tries to associate water
impurities as parameters to human behavior as parameters.

Why do Indians always sound so defensive about their practices? As someone
whose parents spent a decade in india- they attributes their happiness to the
lifestyle they learnt in india. None of which had a clear basis in modern
science.

~~~
1024core
> You probably mean- I haven't seen any research that tries to associate water
> impurities as parameters to human behavior as parameters.

That's what I mean, but I put it more succinctly.

> Why do Indians always sound so defensive about their practices?

Um... because I'm a scientist, and I haven't seen any peer-reviewed scientific
articles on this subject?

Why do (some) Indians always have a chip on their shoulders? See, both of us
can play silly question games.

------
xg15
For people who where wondering how this would even work on a technical level,
the article contains a few pleasantly concrete examples:

> _When the researchers investigated the microbiomes of [mice who avoid social
> contact], they found the animals lacked a common species called
> Lactobacillus reuteri. When they added a strain of that bacteria to the
> diet, the animals became social again.

Dr. Costa-Mattioli found evidence that L. reuteri releases compounds that send
a signal to nerve endings in the intestines. The vagus nerve sends these
signals from the gut to the brain, where they alter production of a hormone
called oxytocin that promotes social bonds.

Other microbial species also send signals along the vagus nerve, it turns out.
Still others communicate with the brain via the bloodstream._

~~~
tsomctl
One of the many chemicals that your gut bacteria produce is butyrate, a short
chain fatty acid. Butyrate has many uses in your body, including feeding other
gut bacteria, feeding the epithelial cells in your intestines, has anti
inflammatory properties, used as a neurotransmitter, and encourages the
production of growth hormones. Your gut bacteria also produce a number of
other chemicals, including many vitamins.

There are at least 400 different species living in a healthy person's gut
(it's difficult to define a species, since they transfer dna between
themselves.) Many of these we haven't been able to successfully grow in a lab.
Their primary food is resistant starch, which is starch that your small
intestines can't split apart and absorb. There are a number of different types
of resistant starch, which basically comes down to how the chains of glucose
and fructose molecules are arranged. Different bacteria prefer different types
of resistant starch, and thus you can majorly influence your biome just by
changing your diet. There's a special diet called FODMAP which supposedly
helps with IBS and related diseases. I also think that a number of fad diets
main benefit is influencing your gut bacteria.

------
AnIdiotOnTheNet
This really isn't that surprising is it? The human body relies on so many
microbes that do not share what we consider to be "our" genes to function,
wouldn't it be odd if those microbes didn't have a communication channel with
the brain? I guess people are still subconsciously uncomfortable with the idea
that what they consider to be their self is a communal organism?

~~~
neuronic
I studied bioengineering and bioinformatics and have often brought up this
idea in conversations. Honestly, I think it's more that people simply don't
realize / have ever thought of it because most are quite receptive to it.

But sure, I have also gotten quite the negative reactions but it tends to be
the same monkeys who dismiss anthropogenic climate change in the face of
decades of evidence.

~~~
reitanqild
> But sure, I have also gotten quite the negative reactions but it tends to be
> the same monkeys who dismiss anthropogenic climate change in the face of
> decades of evidence.

Not denying anthropogenic climate change but until recently fat was dangerous
and sugar was less dangerous. This goes back to the thirties, so definitely
decades.

Worse, when some of the loudest voices in the climate camp not only fly across
the globe to climate conferences but in private jets, then you can understand
why people are sceptical. (1400 private jets this year?)

Same with the EAT campaign: travelling around the world in luxury, telling
other people they can basically forget their current lifestyle.

I'm not saying it isn't right.

Personally I travel with public transit (bus, train, bus or walk) for a good
hour to work and the same back home. I try to do reuse, repair and recycle in
my household. We coordinate with 4-5 other families to get kids to soccer /
other activities 3 times a week with as few cars as possible. It actually
makes a lot of sense too.

But it is not like we get any support from the thought leaders who fly around
in a luxury we have a hard time imagining even. I can very well understand why
people don't believe.

So can we stop calling other people monkeys? If your are going to make a
change you have to learn to make those people care. And you don't do that by
calling them names.

------
oil25
They're saying, "for the love of God, feed us some fiber, which is only found
in whole plant foods!"

> Less than 3% of Americans get even the recommended minimum adequate intake
> of fiber. On average, we get only about 15 grams a day. The minimum daily
> requirement is 31.5, so we get less than half the minimum. Men are
> particularly deficient. If we break down intake by age and gender, after
> studying the diets of 12,761 Americans, the percent of men between ages 14
> and 50 getting the minimum adequate intake is zero.

[https://nutritionfacts.org/2015/09/29/where-do-you-get-
your-...](https://nutritionfacts.org/2015/09/29/where-do-you-get-your-fiber/)

~~~
SamReidHughes
Keep in mind that recommended daily requirements are not indisputable science,
the phrase "made-up nonsense" comes to mind. The fact that only 3% of the
population meets the guidelines but do just fine is proof of this.

I think we'd get fiber cravings if we were truly deficient.

~~~
chillacy
Agree that dietary requirements are unscientific, though not sure cravings
actually work that way, it would've saved a lot of lives if sailors with
scurvy got citrus cravings or something.

~~~
Reason077
Undoubtably, sailors on long ocean voyages really did crave the fresh foods
(fruit, vegetables, meat) which would have contained enough Vitamin C to
prevent (and reverse) scurvy.

The problem was these were often not actually available on their voyages.

~~~
TeMPOraL
Were they actually _craving_ those foods, I think the solution to scurvy would
have been discovered almost immediately.

Alas, the human body rarely if ever communicates useful solutions in this way.

------
wtmt
> Following a string of similar experiments, he now suspects that just a few
> species in the gut — perhaps even one — influence the course of Alzheimer’s
> disease, perhaps by releasing chemical that alters how immune cells work in
> the brain.

> He hasn’t found those microbes, let alone that chemical. But “there’s
> something’s in there,” he said. “And we have to figure out what it is.”

This entire article has many facets that are quite interesting, and we just
can't wait for substantial research in this area to reach well supported
conclusions and remedies for people with different conditions.

~~~
ruytlm
This[0] article was posted somewhere here a while back I believe, and is a
potentially related approach to Alzheimers.

[0]: [https://www.statnews.com/2018/10/29/alzheimers-research-
outs...](https://www.statnews.com/2018/10/29/alzheimers-research-outsider-
bucked-prevailing-theory/)

------
Dirlewanger
Dr. Rhonda Patrick was on Joe Rogan's podcast and she went into the chief
importance of the gut microbiome
([https://www.youtube.com/watch?v=sOodMDndr4Q](https://www.youtube.com/watch?v=sOodMDndr4Q)).
Like I knew eating healthy/exercise/etc. was all good, but she went in-depth
on how crucially important eating the right foods was to so many other systems
in your body, and I just had no idea of all of it.

------
peteretep
> a common species called Lactobacillus reuteri. When they added a strain of
> that bacteria to the diet, the animals became social again.

How do I summon Gwern to do some self-experiments?

------
eaguyhn
NHK has a great documentary series, "The Body". This episode focuses on the
microbial activity in the gut:
[https://www3.nhk.or.jp/nhkworld/en/tv/documentary/20181021/4...](https://www3.nhk.or.jp/nhkworld/en/tv/documentary/20181021/4001308/)

