
Fiber-Famished Gut Microbes Linked to Poor Health - roye
http://www.scientificamerican.com/article/fiber-famished-gut-microbes-linked-to-poor-health1/
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jrapdx3
The problem with this article are statements about value of "fermentable"
fiber without giving any real info about the nature of such fiber. (Except
it's not digested by gut enzymes, hence "leftovers" that colonic organisms may
be able to "ferment".)

There are _many kinds_ of dietary fiber, it's actually quite a complex
subject. The basic classification of "soluble" and "insoluble" is not very
informative. As the article says, there are a great number of different
organisms that can inhabit the "biome", each species of bacteria, fungus,
virus, etc. has its own preferred substrates, and produces its own particular
set of fermentation products.

I believe the research on biome activity is complicated by the vast range of
variation among the organisms as well as the sorting out the beneficial or
harmful effects of their activity on the host. And of course, we must not
forget hosts also show a range of characteristics and are dynamically variable
too.

As the article hints, research shows biome effects on many body functions,
such as immune system and metabolic function. However, pinning down
specifically what substrates are important to which organisms producing
helpful/harmful effects is a daunting mission.

It's going to take a great deal more study before we will begin to have any
clear idea about exactly which of the million different forms of fiber is
going to be good (or bad) for any given health issue.

~~~
gmac
More research is always nice, but you can get a long way with the two words I
learned as a biological anthropology undergrad: dietary diversity.

Eating well isn't rocket science. Eat a wide range of foods. Then you'll very
likely hit all the things you need, and not take on harmful amounts of the
things you don't. Plus you'll get to enjoy the variety along the way.

~~~
davak
As a physician I think the diversity hypothesis should really be challenged.
Our guts, microbes, and even genes take a while to change. Is diversity really
helpful or harmful?

When you study people that live to be very old, many of them eat the same
simple things on a daily basis for decades.

Anyway, just a personal hypothesis...

~~~
pavedwalden
As an interested layman, I've wondered about this myself. Ecosystems take a
while to stabilize around local maxima. So, although diversity may prevent you
from falling into any particular deficiency, it seems possible that a well
balanced diet that remained stable over time would allow your flora to really
dial in.

~~~
sten
You could also be avoiding potentially harmful substances which a diverse diet
might have exposed you to. That they lived into their 90s on the same diet
they had in their 20's implies they skipped TV dinners, Aerosol Cheese and
McDonalds along the way.

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mark_l_watson
I used to be more careful what I ate, but in the last few years I started a
simpler approach: about 60% of my diet is vegetable matter (bok choy, carrots,
broccoli , etc. in the winter -- more squash, tomatoes, etc. in the summer).

To the point of the article: I do like fermented foods. My home made pressed
cabbage being a favorite, but a local health food store features locally
produced live sauerkrauts, kimchi, etc. All tasty stuff.

I think that it is pretty simple: avoid sugar, avoid processed food, and then
whatever you eat enjoy it.

~~~
maxerickson
I think I've said this to you before, but you need to use some other word than
processed. Especially if you are talking about fermented foods being good, as
that is sort of a classic way of processing food.

Maybe 'refined'? Or even, 'excessively refined'?

~~~
mark_l_watson
Thanks Max, I should have made that more clear. By 'processed' I intended not
eating packaged foods (cereals, frozen food, bread with lots of preservatives,
etc.)

Basically, starting with fresh ingredients and cooking food yourself. In some
areas, I have found inexpensive restaurants that do this. There was a
vegetarian restaurant my wife and I liked in Milpitas California, about 10
miles from the Googleplex, that I would like physically moved to the town I
live in :-) Seriously, you could look back in the kitchen and see lots of
fresh food, food was made to order, and their prices were low.

We like to cook, but I realize that not everyone has the time to cook from
fresh ingredients.

~~~
maxerickson
_but a local health food store features locally produced live sauerkrauts,
kimchi, etc. All tasty stuff._

Neither fresh nor prepared by you...

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dmichulke
It almost sounds too good to be true.

(Just like "enough vitamins", "no fat", "no trans-fat", "no cholesterol", "no
carbs", "enough poly-saturated fat", "enough omega 3" seemed to be _the_
solution before)

Anyone with background knowledge can reason for or against the article?

~~~
dlss
In general, eating the same diet as thin/healthy people will cause your
microbiome to shift toward the microbiome of thin/healthy people. This is
because your microbial population is largely determined by resource
availability and resource type, and adaptation happens quite quickly (ie
speeds not unlike those shown in
[http://www.youtube.com/watch?v=Pb272zsixSQ](http://www.youtube.com/watch?v=Pb272zsixSQ))

However, I believe it's wrong to conclude that thin/healthy people have the
kind of microbiome you should be aiming for.

The microbiome you want (or rather I want) is the one my ancestor's had, just
like I want the food I eat to be similar to the food my ancestor's ate.
Unfortunately this is basically impossible given modern farming techniques,
which remove most of the food-borne microbes found on natural crops.

See [http://humanfoodproject.com/rebecoming-human-happened-day-
re...](http://humanfoodproject.com/rebecoming-human-happened-day-
replaced-99-genes-body-hunter-gatherer/) for more on this from the founder of
the American Gut Project.

~~~
cbd1984
> The microbiome you want (or rather I want) is the one my ancestor's had

Why? Do you think your ancestors were especially healthy?

Do you think they all had the same microbiome?

~~~
dlss
> Why? Do you think your ancestors were especially healthy?

It's the null hypothesis. For me personally, it's more a bet against the
modern microbiome than it is a bet for the ancestral one.

See also paleo vs margarine, no fat, no cholesterol, no carbs, enough poly-
saturated fat, enough omega 3. Really paleo vs any nutrition advice that's
more than 10 years old (so the science had a chance to check the claims)

IMO we don't currently know enough about nutrition or the microbiome to make a
better choice than "whatever our great-great-great grandparents did"

> Do you think they all had the same microbiome?

They didn't, but they had way more diversity and significantly different
strains than moderns do. Check out my above link to the american gut project's
founder or
[http://journals.plos.org/plosone/article?id=10.1371/journal....](http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0106833)

~~~
msandford
I think it's bananas that you're advocating for historical eating and getting
downvoted. The only reason we're here at all is that it worked well enough to
keep people alive.

Maybe it's not "optimal" but considering that obesity, heart disease,
diabetes, cancer, etc rates have all been climbing like crazy for the last 50
years and the diet has changed a lot in the last 50 years, it's not outside
the realm of possibility that the change in diet is causative towards these
outcomes rather than simply correlated.

And considering how long it's going to take to sort it out definitively, you
might have to go most of your life making decisions based on a hunch rather
than with proven science. It sucks, but that's life.

~~~
genofon
>heart disease, diabetes, cancer, etc rates have all been climbing like crazy
for the last 50 years I'm not sure about that, in the past the diagnosis were
really different from now so you can't really compare them.

Also the lifespan was much shorted at that time, so people had less changes to
get these illnesses.

~~~
will_work4tears
So are you arguing that obesity in children is happening because we are living
longer?

~~~
DanBC
It's not controversial to say that cancer is a disease of old age, and that
rates of cancer are higher now because people are living longer.

That makes a lot more sense than a lot of the nutrition bullshit that gets
posted to HN.

~~~
tokenadult
Dan, I know you like to check your facts. Age-adjusted _rates_ of cancer have
been going steadily down throughout our lifetimes. That information has been
posted to Hacker News before.

[https://news.ycombinator.com/item?id=8827382](https://news.ycombinator.com/item?id=8827382)

Yes, the absolute number of cancer cases experienced by an individual over the
course of life will increase if the individual lives longer by surviving other
causes of death, as cancer is mostly a disease that takes a long time to
develop. But at a given age, individuals in the developed world are at less
risk than ever before to have a case of cancer, and cancer cases are less
likely to have fatal outcomes than ever before.

------
Singletoned
Finally I have an excuse for all my farting.

