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The body’s microbial community may influence the brain and behavior (nytimes.com)
153 points by bookofjoe 20 days ago | hide | past | web | favorite | 63 comments

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.

Curiously, they may be right - see "Lithium in drinking water and the incidences of crimes, suicides, and arrests related to drug addictions." https://www.ncbi.nlm.nih.gov/pubmed/1699579

The same can be said of lead. I'm fairly certain I've read of a study / theory that the drop in crime rates can be tracked back to removing lead from paint, gasoline, etc.

Full disclosure: I don't recall if this jumped the gap between correlation and cause.

I think that explanation is pretty widely accepted as being a cause of the past few decades' drop in crime rates (though not the only one). It's probably not possible to prove cause better than we have without obviously unethical experimental studies.

Obviously unethical government policies might suffice: Flint, MI.

As a side note, n=1 thing, over the counter lithium orotate is great for me as a mild anxiolytic when work related stress kicks in.

"There must be something in the water" and variations thereof is a common saying in the west, too. It's often heard as a response to learning that families of tall people or smart people come from the same town.

Let me play the devil's advocate for a just moment: water in the west is much more regulated. I doubt that some small difference in our water's mineral levels would change much in the brain. Something like chemicals or harsh or bacteria from heavily polluted water might be really different. Rivers downstream from pharmaceutical labs, heavy industrial area, etc. could mess up your body's balance.

e.g. http://www.asianews.it/news-en/(East-Asia,China)-Shandong-fa...

> Let me play the devil's advocate for a just moment: water in the west is much more regulated. I doubt that some small difference in our water's mineral levels would change much in the brain.

Different water softness, different strains of bacteria. Back to step one.

Tell that to the thousands upon thousands affected by lead poisoning in the West. The "heavy" regulations are not that comprehensive.

If there were no regulations, the water in those cities would be the same to this day and wouldn't have made the headlines. A law is only as good as it is enforced. The Flint water crisis should be big enough of a wake up call to put the focus on the EPA and Safe Drinking Water Act (SDWA) and hopefully avoid similar issues in the future.

The situation is miles better than it was in the 1950s thanks to those regulations.

"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.

> 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.

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

I'd be tempted to sound defensive on scientific subjects if my country were taking this route: https://www.bbc.com/news/world-asia-india-46778879

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

I feel like that's a broad overgeneralization, but regardless I'd wager a guess that it would have something to do with not wanting to sound like a charlatan or a fool. Even if it works for them, people can be awfully bristly about health and lifestyle practices when it comes from someone they don't know.

A similar saying exists in Turkish as well.

If a relative of yours moves to a far away town and comes back for visit and he acts very differently from how he used to, you might say to him: "oh that place's water has changed you".

Hmmm, Rome, Flint MI, . . .

I also just saw a video about 60 years fox breeding experiment in Russia to see how selection would change their behavior (they're now tame to human, not dog friendly but halfway).

Consider this to the relationship between climate/location/genes/culture.

I'm not sure what connection you're trying to make. Selective breeding is textbook "nature", and effects of things like the local composition of water is textbook "nurture".

not if people live there for ages, it will end up as selective pressure toward peers and future generations

But the comment you replied to mentioned how moving to a place could change your personality even as an adult.

yes and these adults might settle unknowingly

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.

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.

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?

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.

> 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.

Also, further on the "just because you don't see or know doesn't mean absence" front- a lot of health issues don't manifest in weeks or months. Sometimes things accumulate over years. Something that FDA (or really the pharma companies) don't want you to think about.

I don't think it's that the FDA or pharma companies don't want you to think about, I think it's just very difficult to properly study the effect of things that take a lifetime to manifest.

I'm inclined to believe this as well. It's so hard to get a statistically significant effect and approval for drugs that are worth billions of dollars, that there's simply little incentive to study and promote "natural" alternatives.

Maybe moving to a city with better drinking water is the best move for a small subset of the population. There's no sinister cabal trying to hide this, there's just no incentive for anyone figure this out for you in an individual basis.

I could see pharma working the other way though. If you could identify a location with a population who exhibit a deficiency and your drug is more effective there, there's an incentive to better promote it there. I don't think the industry is sophisticated enough at this point to accurately track this though, as individual patient response is difficult to measure and report on.

Source: dated someone that did marketing for one if the top 5 pharmas.

I think its more likely that the resistance to this idea is based on peoples addiction to quick fixes from well-marketed pharmaceutical products than anything else. Having been totally convinced by ones local authority that ones mental health issues are all a result of a lack of proper chemical balances in ones brains, being told that its really all about what you eat is .. unsavoury .. to those with a consumer-oriented mindset, who mostly just want to take a pill to solve problems while also being granted immunity from responsibility for ones dietary choices ...

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.


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.

When you eat fiber, your body produces bile to digest it. Because it's hard to digest, you produce more bile. Bile is made from cholesterol, so a high intake of fiber directly reduces cholesterol levels. If you believe high cholesterol levels increase cardiovascular disease risk, then increasing fiber decreases cardiovascular disease risk which is the largest killer of Americans.

Another major benefit of fiber is that is slows down the breakdown of long-chain carbohydrates because you dilute them with long-chain cellulose carbohydrates that our body can't breakdown. This slows their absorption into the blood thus smoothing out sugar entry and subsequent insulin increases. Insulin sensitivity is a major health issue, typically showing up as diabetes and other metabolic disorders.

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.

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.

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.

I got grapefruit juice cravings when experimenting with polyphasic sleep in college, and I had never had the desire to drink grapefruit juice at the college cafeteria before then.

That's interesting, but yeah, I'm not sure either. I've managed to ignore my body's signals regarding food in all sorts of destructive ways.

US population is not doing just fine when it comes to nutrition and overall health. What is wrong would make a very lengthy article on its own, but I guess we can agree there are definitely things to improve, and this could be one of them.

One of the reasons we might not be having fiber cravings is, we don't need it for ourselves per se, but foreign, albeit friendly gut bacteria. It is possible for bacteria to manipulate its hosts ie by releasing some enzymes, but maybe we didn't evolve our symbiosis that far yet. Or we're drowning those cravings into more intense ones like sugar or other addictions.

If only half of the population is doing fine, 6% of them are hitting that fiber number.

I'm not sure we can say we all "do just fine" on a low fiber diet. The current #1 killer in most Western countries is heart disease and we know high fiber diet decreases the risk of developing heart disease. High fiber diets also decreases the risk of other very, very common aliments like stroke, obesity, and type 2 diabetes.

I badly crave donuts, especially on weekends; I can't come to the conclusion my body requires more donuts.

I don't think they are doing just fine. It's likely that they are having subtle issues that they aren't aware of and just accept them as is.

Can’t believe I’m going to say this, but sugar free Metamucil is an amazing life hack. Makes going to the bathroom way easier.

Large swathes of the US now have an ALDI supermarket where you can buy genuine German schwarzbrot. Much tastier than psyllium husk in orange juice, although fans of white bread will find it a bit chewy at the beginning.

Come to Denmark, we have 100's of different kinds of rye bread that is significantly better than schwarzbrot. Or just make it yourself, it's not difficult.

We have "smørrebrød" which is quite delicious, and there is something for everyone. One particular famous smørrebrøds restaurant has a list of over 200 different kinds to choose from.

I buy psyllium husk in bulk and just add it like a condiment. Great with any egg dish.

And yet, those people are still alive and well. What is the problem with getting less fibre than recommended?

Alive but I wouldn't call modern humans the paragon of physical fitness.

Subpar health. I'm no specialist but fiber is said to feed beneficial bacterias in your lower intestines. This has a dual effect:

- if not fed right, these bacteria may consume gut mucus, causing inflammation

- when fed right, they actually improve digestion efficiency

thus, in theory, proper diet can get you from chronic diseased [with the usual western medicine prescriptions] to healthier+more energetic

Just the last six months or so I've seen educated people posting in my feeds about how fiber might just be included in foods that are beneficial, with fiber itself not being so.

Well, not that it matters for me since I have Crohn's and can't really eat fiber at all.

I started taking these to supplement my diet and it made me feel so much better: https://smile.amazon.com/GNC-Fiber-Gummy-Strawberry-BlackBer...

To provide a counterpoint:

- Fiber doesn't ward off colon cancer, according to the Harvard School of Public Health: "For years, Americans have been told to consume a high-fiber diet to lower the risk of colon cancer [...] Larger and better-designed studies have failed to show a link between fiber and colon cancer."

- Fiber doesn't reduce the risk of heart disease, according to the American Heart Association: "A fiber supplement added to a diet otherwise high in saturated fat and cholesterol provides dubious cardiovascular advantage." Furthermore, these supplements caused "reduced mineral absorption and a myriad of gastrointestinal disturbances" - factors that in fact, contribute to heart disease.

- Fiber doesn't prevent breast cancer either, according to the U.S. Center for Disease Control and Prevention. In fact, it's the complete opposite: "Carbohydrate intake was positively associated with breast cancer risk." Fiber happens to be a carbohydrate too, and carbohydrates are the only food that contains fiber.

- Fiber doesn't counteract diabetes, according to the Harvard School of Public Health: "Fiber intake has also been linked with the metabolic syndrome, a constellation of factors that increases the chances of developing heart disease and diabetes." Truth is, fiber requires more insulin or drugs to control blood sugar, and makes diabetes even more devastating.

(excerpts from Fiber Menace by Konstantin Monastyrsky)

On the Amazon page, all of that text comes from someone presented as authoritative, but turns out to be a _chiropractor_.

Chiropractors can't quote Harvard or the CDC?

Even the small excerpt seems to be cherry-picking and mischaracterizing research data.

This is why I never listen to advice and opinions on the internet.

Ehhh... your second point merely shows that fiber SUPPLEMENTS don’t help.

Your third point is probably misleading as you can get enough fiber with very modest carb intake

The fourth follows what seems like a similar dubious path to the third

> 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.

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...

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). 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.

> 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?

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...

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