
Artificial sweeteners linked to glucose intolerance - bensedat
http://www.newscientist.com/article/mg22329872.600-artificial-sweeteners-linked-to-glucose-intolerance.html
======
biot
I like how all the people who benefit from artificial sweeteners are refuting
something which the study doesn't claim. For example:

    
    
      "The International Sweeteners Association (ISA) says it strongly
       refutes the claims made in the study: 'There is a broad body of
       scientific evidence which clearly demonstrates that low-calorie
       sweeteners are not associated with an increased risk of obesity
       and diabetes as they do not have an effect on appetite, blood
       glucose levels or weight gain.'"
    

It's true that artificial sweeteners have no immediate effect on appetite,
blood glucose levels, nor weight gain. None of these are claims made by the
study. Everyone is refuting the immediate effects of artificial sweeteners.
The study claims that _after_ consuming artificial sweeteners, if you then
consume something naturally sweet, the prior consumption of an artificial
sweetener alters your glucose tolerance levels.

It's the equivalent of saying that removing all the trees from around rivers
has no effect on fish population because clearly fish don't live in trees. But
it's the secondary effects of this which such a statement ignores: the
increase in soil erosion impacting water quality, change in water temperature
due to having more direct sunlight, and so on.

Also:

    
    
      "'Decades of clinical research shows that low-calorie sweeteners
       have been found to aid weight-control when part of an overall
       healthy diet, and assist with diabetes management,' says Gavin
       Partington of the British Soft Drinks Association."
    

This has little meaning without having a reference point to compare the
results to. If the study is correct, take one group of people who use diet
soft drinks with an overall healthy diet and compare it to another group of
people who consume the same overall healthy diet but drink water instead of
diet soft drinks, and the group that drinks water should have a better glucose
tolerance response than the diet soft drink group.

~~~
function_seven
You just hit one of my pet peeves. "...when part of a healthy diet". Only
cigarettes fail that test as far as I can tell.

Eating deep-fried Twinkies and a 32oz Mountain Dew is not bad for you, when
done as part of an overall healthy diet.

~~~
dragonwriter
Right, _by definition_ , consuming _any_ food is not bad for you, when done as
part of an overall healthy diet -- any overall diet in which the food was bad
for you would not, _ipso facto_ , be a healthy diet when that food was
included.

The claim would only begin to be _meaningful_ if instead of "when part of a
healthy diet" it was "when included in an _otherwise_ healthy diet".

~~~
graeme
Not necessarily. You could smoke one cigarette now, and you would be _less
healthy_. But if you never smoked again, you would not have transitioned to
_unhealthy_

The first term is relative, the second absolute. If the diet is overall
healthy, it's possible it has some bad food. It's less healthy than if it
didn't, but not unhealthy.

~~~
epaladin
Which just made me wonder if it's possible to train a hidden markov model for
detecting that. Trigger a flag that says "wowzers, now you're in unhealthy
state territory". Otherwise it's real hard to tell if occasional engagements
with unhealthy behaviors are having an impact on health overall. I imagine
we'll get to the point of being able to do this sort of thing in about five
years.

~~~
bitexploder
"In about 5 years" is often code for, "It is really cool, and it seems
feasible, but I have no idea how difficult it really is."

Also, we have the basic capability for this now. Regular blood testing, etc.
Get a physical. Get blood work every 3-6 months. Its just basic stats for your
body. I do this. To me it is like checking the oil levels in a car. Why would
you not collect this type of data for your body, which is arguably one of the
most important "possessions" a person can own?

~~~
graeme
What's included in the blood testing?

I'm in Canada, and the idea of routine blood testing for young people (I'm 29)
doesn't seem to have caught on.

~~~
danudey
That's because our medical system isn't for-profit, so we only get blood tests
when they're medically necessary and not just for convenience.

------
nostromo
Here's a nice write up about the results:
[http://www.newscientist.com/article/mg22329872.600-artificia...](http://www.newscientist.com/article/mg22329872.600-artificial-
sweeteners-linked-to-glucose-intolerance.html)

Note that the mice were given the human equivalent of 18 to 19 cans of diet
soda a day.

~~~
diminoten
From that article:

> The dose of sweetener was the equivalent to the maximum acceptable daily
> intake in humans, as set by the FDA.

Now I realize that I, random commenter from the Internet, am unlikely to find
a fatal flaw in an experiment designed and carried out by folks who do this
professionally, but can someone explain to me why it's okay to give mice a
human-amount of sweetener, and not a mice-amount?

It just seems to me that our larger bodies are probably better capable of
handling... well, most everything, and to start dosing mice with human levels
of sweetener is actually going to cause a much worse reaction than if humans
were to consume that amount.

Edit: Also, it looks like the effects are reversible by "wiping" gut bacteria
via antibiotics. If mice can survive the process of "wiping" gut bacteria, can
humans? Is there a cure for this pre-diabetic state?

~~~
tokenadult
_can someone explain to me why it 's okay to give mice a human-amount of
sweetener, and not a mice-amount?_

This means that the mice got a dose per unit of body weight like what humans
would get if they ate that FDA-defined maximum. That's what equivalent doses
are taken to mean in animal models of human nutrition or medicine. When there
is known to be a different bioavailability or digestive response in animals
from humans, then the dose is adjusted with that in mind before the experiment
begins.

So, no, the tiny bodies of mice were not subjected to the large servings that
much bigger human beings eat. They got a dose adjusted for the body weight of
mice.

~~~
virtue3
it's more than just a "per kg" dosing as well. Rats/mice have a very different
level of metabolism than humans do just because of scale.

Basically there's a fudge factor of 0.75. Of course, the following article
goes on to explain that it's actually drug mechanism dependent as well. Very
complicated stuff!

"The value of the exponent for whole body metabolic rate was originally
calculated by Max Kleiber in 1932 to be 0.74 (Kleiber, 1932). A few years
later, Brody et al. published their famous mouse to elephant curve and
calculated the exponent to be 0.734 (Brody, 1945). A value of 0.75 is now
accepted because it is easier to use, and the difference from 0.734 is
considered to be statistically negligible (Schmidt-Nielsen, 1984). However, it
should be noted that exponents in the range 0.6–0.8 have been reported for
metabolic rate (Agutter and Wheatley, 2004). A value of 0.75 means that the
whole body metabolic rate increases as body weight increases, but to a lesser
extent than would be expected of a simple proportional relationship. It
follows on from this that the specific metabolic rate (the metabolic rate per
unit mass) decreases as animals get larger (the exponent is −0.25); the
metabolic rate of 1 g blue whale tissue is 1000 times less than that of 1 g
shrew tissue (Kirkwood, 1983)."

from:

[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2737649/](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2737649/)

------
skue
For those not aware, other studies have shown that consuming diet soda may
actually increase the chance of obesity. So that is not necessarily news. If
you are curious, here is a pretty good study (full text):

[http://onlinelibrary.wiley.com/doi/10.1038/oby.2008.284/full](http://onlinelibrary.wiley.com/doi/10.1038/oby.2008.284/full)

More recently, studies have tried to determine whether there is a satiety or
protein mechanism that can explain this, whereas this new study demonstrates
that gut flora may play a role.

This needs to be confirmed, and there may still be other mechanisms at play as
well, but it is interesting.

(Disclaimer: I do have a healthcare background, but am not a researcher in
this field. Would be happy to hear more from anyone who is.)

~~~
jonnathanson
Indeed. I think it helps to unpack the various claims being studied:

1) Carcinogenicity. Do certain sweeteners cause harmful mutations and increase
cancer risk? This is one of the oldest and most frequent allegations,
especially against saccharin and aspartame. Mostly inconclusive, though both
sweeteners have been exonerated at least as often as they've been accused.

2) Insulin triggering. Artificial sweeteners may not bear the caloric load of
sugars and starches -- but do they trigger the release of insulin, just the
same? Again, the jury is still out, but certain sweeteners (aspartame,
sucralose, and possibly saccharin) are looking suspect.

3) Caloric load. Some sweeteners and putatively indigestible molecules (sugar
alcohols, "resistant starches," etc.) may contain more _effective_ calories
than in vitro studies predict them to contain. This is because the chemicals
aren't digested in the traditional sense, but are fermented and absorbed in
the gut. Caloric bioavailability is often different from nominal calorie
count. (Indeed, this is the entire principle behind the supposed benefits of
resistant sweeteners and starches; those benefits may have been overstated or
misunderstood).

4) Disruption or adverse selection of gut microbiota. As detailed in this
study. While not all sweeteners have been implicated here, this field of study
is only just kicking into high gear. It seems reasonable to suspect that
molecules fermented by / consumed by gut bacteria could have _some_ effect on
flora composition. Many sweeteners fit that criterion.

5) Other toxicities. Liver or kidney toxicity, neurotoxicity, endocrine
disruption, etc. As with carcinogenicity, the jury is still out. Unlikely for
some sweeteners that are not metabolized via these pathways. Possible for
others. Most sweeteners (all?) on the market right now are generally
recognized as safe in this respect, despite popular beliefs to the contrary.
Notable exceptions exist for those with rare metabolic or genetic disorders,
such as phenylketonuria (aspartame contains phenylalanine).

6) Side effects. Some sweeteners, particularly those in the sugar alcohol
family (and sorbitol especially), can cause laxative effects and other GI-
related issues. Individual tolerance can vary. Breaking this category out from
#4 because the action here can be purely mechanical (i.e., increasing
intestinal water absorption).

I'm not a doctor or medical researcher myself. Just an interested nerd. But I
have been following this area for awhile. I welcome any corrections, comments,
or additions from people more knowledgeable than I am. I assume there are many
such people on HN. :)

~~~
jrapdx3
Good list. Among the patients I see metabolic disturbances rank high on the
list problems to manage. Some people complain of adverse effects of NAS such
as headache, GI symptoms, but in the clinical setting, it's very hard to
establish connections between NAS and metabolic syndrome manifestations like
DM2.

The article says mouse fed _any_ of 3 common NAS in water with/without glucose
developed "glucose intolerance", which I take to mean above-normal glucose
levels. That would point to either impaired insulin production or increased
insulin resistance. I think the latter is much more likely.

This probably occurs in some humans too (among people genetically predisposed
to develop DM2). Of course that's my extrapolation of the info, but seems a
likely direction of future research. Getting insulin levels and measuring
insulin resistance after NAS feeding are logical steps to take.

I agree with your comment and others that the role of colon microorganisms is
a truly fascinating subject, and remains quite a mystery. Other research shows
gut flora are distinct among host species. The evolution of these microbes
appears intimately bound to the evolution of their host, but the nature of the
link is unknown. Odds are unraveling the story of the numerous friends within
(and all over) us will fill in important gaps in our knowledge in surprising
ways.

------
jimrandomh
The headline is suspicious, but unfortunately, this article is paywalled, so I
can't tell what's really going on. The main problem with the headline is that
it lumps together "artificial sweeteners" as a category, when that is in fact
a pretty widely varied class of molecules.

~~~
glaugh
Agreed. From the article Nostromo just posted[1], looks like the mouse models
were based on aspartame, saccharin, and sucralose, and the human subjects were
taking saccharin.

[1]
[http://www.newscientist.com/article/mg22329872.600-artificia...](http://www.newscientist.com/article/mg22329872.600-artificial-
sweeteners-linked-to-glucose-intolerance.html#.VBnjFWRdX4K)

------
mratzloff
FDA acceptable daily intake (ADI) for aspartame is 50 mg per kg of body
mass.[0] For an individual 180 pounds, that's about 82 kg. That means his ADI
is 4100 mg. Aspartame in popular diet sodas is between 50 and 125 mg.[1]

You'd have to drink A LOT of diet soda to reach these levels.

[0]
[http://www.cancer.org/cancer/cancercauses/othercarcinogens/a...](http://www.cancer.org/cancer/cancercauses/othercarcinogens/athome/aspartame)

[1]
[http://static.diabetesselfmanagement.com/pdfs/DSM0310_012.pd...](http://static.diabetesselfmanagement.com/pdfs/DSM0310_012.pdf)

~~~
lucaspiller
I have a friend who used to drink nothing but Diet Coke. He went through a few
2l bottles a day. According to that link (assuming it's the same in Europe),
Diet Coke is 125mg per 8 ounces, so a 2l bottle is 125 / 8 x 70.4 = 1100mg. So
if he drank four 2l bottles, that's over the daily limit.

------
sadfaceunread
This is an impressive piece of work but I worry that a larger amount of work
is needed in the relationship between glucose intolerance, diabetes and
metabolic syndromes in general. The fact that glucose intolerance is induced
by a high sugar diet and leads towards a path of clinical outcomes ending in
diabetes, doesn't necessarily indicate that glucose intolerance developed via
artificial sweetener consumption is indicative of being on the same clinical
pathways towards metabolic syndrome and diabetes.

------
themgt
I'd be curious if they tried this study with xylitol. I chew xylitol gum for
dental health and from my understanding it's not thought to contribute to
metabolic problems in reasonable quantities:

[http://en.wikipedia.org/wiki/Xylitol#Diabetes](http://en.wikipedia.org/wiki/Xylitol#Diabetes)

~~~
whyenot
Xylitol was not included in the study. Because xylitol is absorbed more slowly
from the gut and gut microflora appear to be the mechanism of action found in
this study, I'd personally be at least a little concerned.

Mice in this study were given sweeteners for 11 weeks, long enough that their
use apparently led to changes in microflora which were associated with glucose
intolerance. Existing studies of xylitol could well be for much shorter
lengths of time and might not have been able to detect these kinds of changes.

~~~
yupmetoo
I wonder then if its the absorption of the gut or if it is the conditioning.
If the gut flora have to adapt to trying to break down an impenetrable
compound they might become super strong at breaking down simpler molecules no?

------
sp332
Does this mean diabetes could (in some cases) be caused by gut bacteria? Can
we reduce diabetes risk factors with targeted antibiotics that attack certain
glucose-intolerance-causing bacteria?

~~~
jonnathanson
It's fiendishly difficult to pry apart correlation and causation for complex
conditions like diabetes (which we're steadily reconceptualizing as less of a
"disease," and more of a chain reaction of metabolic and hormonal disorders).
Changes in gut bacteria are _associated_ with the condition sometimes called
"pre-diabetes," or a "pre-diabetic state." But we're not yet sure if they are
a causative factor, if they are the result of the condition, or if they're
simply co-morbid with it.

Whatever the case, gut bacteria appear to play a vital role in our metabolic
health, and we're only beginning to explore this area in earnest.

------
kens
This result seems pretty strange to me - why would artificial sweeteners
affect bacteria's metabolism in this way?

It seems like a bizarre coincidence that bacteria would react in the same way
to three different sweeteners, unless they have receptors that happen to match
human taste receptors (which also seems unlikely). In other words, to bacteria
these sweeteners should just seem like unrelated random chemicals.

(I read the Nature paper - most of it looks at saccharin since that had the
strongest response, but all three artificial sweeteners caused marked glucose
intolerance.)

~~~
lnanek2
Bacteria are, in general, much more capable at processing various chemicals
than humans are. They can even pass around packets of genetics, called
plasmids, across species. So it isn't really surprising if bacteria can
flourish eating something that tastes sweet to people, but doesn't provide any
calories to people. There have been some artificial sweeteners shown to hurt
bacteria more than people - Xylitol is famously used in gum, for example,
because it costs bacteria energy to try to eat it, but they gain nothing, thus
helping to fight bacteria growth.

~~~
calinet6
Aspartame is essentially just a collection of amino acids, so it's even more
feasible (in a total guessing hand-wavey way) that gut bacteria would be
affected.

------
kazinator
This seems misleading.

If you go through the graphs and results, what emerges is that only the
sweetener saccharin has that altering effect on the gut bacteria. I cannot
find among the results any claim that the other NAS that were studied
(sucralose and aspartame) have the effect.

The thing is that saccharin is not widely used any more. If saccharin is found
to be harmful, that is nice to know, but not highly relevant.

------
blackbagboys
The New Scientist article notes that four of the seven human subjects who
consumed three to four sachets of sweetener a day saw a significant change in
their gut bacteria.

As someone who has consumed significantly more than that for a very long time,
my question would be, did their gut flora reconstitute itself after they
stopped using the sweetener? And if not, how could you go about repopulating
your microbiome short of a stool sample?

~~~
uladzislau
The gut flora is as resilient as any other part of human body. It might take a
significant time though. I've heard Korean food helps a lot because it's
fermented. Also usual bifido youghurts you'll find at any grocery store.

------
oomkiller
This seems very misleading. The abstract (available without paywall) mentions
a group of sweeteners, whereas the findings seem to show that only saccharin
has these negative effects. I feel like NAS are probably bad, but without
evidence to support it they should not claim that in the abstract.

------
rcthompson
For some biological context, we have taste receptors in our digestive tracts
identical or nearly identical to those on our tongue, only the ones in our
digestive tract are not hooked directly to sensory neurons, but instead
trigger endocrine signals and such. Since the receptors are identical, then
anything that tastes sweet on your tongue will activate these receptors as
well. If I recall my metabolism course correctly, studies have found that
artificial sweeteners can trigger insulin release through these receptors in
the same way as real sugar (leading to possible hypoglycemia as your body
compensates for a rush of sugar that never comes).

So basically, I have no trouble believing that artificial sweeteners can have
many of the same long-term health effects as excessive consumption of real
sugar, since they're already known to have many of the same short-term
effects, including effects on insulin regulation.

------
lee
So given a choice, between Diet Soda vs. Normal Soda, what would be worse for
your overall health?

I imagine even with increased glucose intolerance, you're still better off
choosing Diet?

~~~
dragonwriter
You're probably better off _not choosing carbonated liquid candy_ \--
especially not doing so regularly and in significant quantities -- even if the
sweetener happens to be non-caloric.

And the point where you've reduced your choices to regular soda vs. diet soda,
you've already failed.

~~~
tedunangst
Failed at what?

~~~
marcosdumay
Failed at having a healthy diet. (That is, if he does make that choice
frequently - a one time event probably won't change anything.)

~~~
parasubvert
In what way is it unhealthy? Aspartame has zero calories, and decades of
studies showing its safety.

Put another way, if you want to avoid sugar (which is much less healthy than
aspartame), besides water, there's tea, coffee, flavoring mixes like Crystal
Light, and various prepared sugar free soft drinks. Many prefer variety over
water. There's little scientific basis to believe drinking any of these things
are bad. Drinking a mix of these is quite a bit healthier for an adult than
chugging juice or sugared drinks - unless you're explicilty trying to carb-
load. Milk is a healthy alternative but debatable due to its effects on some.

------
voidlogic
I'm not really surprised Saccharin isn't great for you personally- but this
isn't so damning there are many other artificial sweeteners to choose from.

[https://en.wikipedia.org/wiki/Sugar_substitute#Artificial_su...](https://en.wikipedia.org/wiki/Sugar_substitute#Artificial_sugar_substitutes)

I'd of course like to see them all studied in this manner.

------
mladenkovacevic
I hope this doesn't hold true for stevia as well :/

~~~
medell
Pure stevia is not artificial, but the verdict is still out on safety. It
seems to be OK... for now. I use it, though I try to use honey as well.

~~~
UrMomReadsHN
The stevia whole leaf has been used for centuries in teas on Brazil. It has
been used as an artificial sweetener in Japan for decades accounting for
around 40% of the sweetener market there. Weirdly, I always bought it labeled
as a dietary supplement in the US before the FDA approved some extracts as
food additives.

------
mcmancini
Overall, this was a nicely done study. The microbiome is fascinating and an
exciting area of research.

One criticism however would be that the dose of artificial sweetener tested
was atypically high.

It'll be neat to see further research into the cause of variable responses of
the subjects to the artificial sweeteners.

~~~
cschmidt
According to the New Scientist article others have linked to, the equivalent
human dose was 9-12 packets of sweetener a day. I'm sure there are heavy
coffee drinkers that go through that much.

I also don't like those studies where the human equivalent dose is like 50
pounds of sweetener a day, or something silly. This one isn't so bad.

~~~
mcmancini
I guess I'm having trouble figuring out where the numbers are coming from.

I'm seeing that the FDA recommended maximum dose for aspartame is 50mg/kg/day.
Assuming a 70kg Standard Man, that's 3.5g/day of aspartame. Diet Coke has
125mg per 12oz. can, so that would be 28 cans/day. Each packet should be
around 35mg aspartame, so 100 packets/day (the amount of aspartame per packet
was hard to find, and the approx. was from an American Cancer Society
article).

Agreed that 9–12 packets doesn't sound like much, but I think we're talking
way more than that.

------
pistle
The industry takeaway should be to try to isolate the bacteria that play the
secondary part in the glucose resistance, then put ANOTHER additive in the
drinks to kill that bacteria, then sell a more expensive NEW zero calorie
drink?

People like sweet. Let's make sweet safe.

------
duschang27
Abstract can be found here.

[http://www.nature.com/nature/journal/vaop/ncurrent/full/natu...](http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13793.html)

------
raverbashing
This raises more questions than it answers I think (which is a good thing)

1 - Is there such thing as a "sweet base"? Our tongues perceive sweeteners as
sweet (duh) but it seems it mimics sugar in a way for bacteria as well.

2 - From the article "Wiping out the rodents' gut bacteria using antibiotics
abolished all the effects of glucose intolerance in the mice. In other words,
no bacteria, no problem regulating glucose levels."

Soooo... Bacteria affects absorption of glucose? They consume it? They change
the intestinal PH? Or something else?

------
driverdan
Can someone post the full paper? The charts shown at the bottom seem to
contradict some of their conclusions and implications. For example, some of
the sweeteners seemed to result in lower chow consumption and increased energy
expenditure. That would be a positive effect that isn't mentioned in the
abstract.

------
SCHiM
Can anybody explain or guess what the consequences of this intolerance are or
could be?

~~~
ddebernardy
You might find this video on fructose and metabolic disease (of which glucose
intolerance is a symptom) interesting:

[http://www.youtube.com/watch?v=dBnniua6-oM](http://www.youtube.com/watch?v=dBnniua6-oM)

~~~
pyre
It's worth noting that there are many critics of this guy.

~~~
ddebernardy
True. As I understood them though, the criticism was primarily about his
message that fructose would be the key or only reason of metabolic syndrome,
or his depiction of sugar as pure evil rather than as something which you can
consume in small amounts, more than about the effects of fructose itself.
(When not, connections between the critic and the sugar or food industry were
quick to Google, thereby reducing the credibility to zero.) This may have
changed since I spent time digging into it, though, so please expand if it
has.

~~~
pyre
My point was just to point out that criticism exists. Loads of people watch
that video and don't do other research on the topic.

------
FranOntanaya
Do they compare pure sweetener diet with pure sugar diet calorie per calorie,
and sweetness units per sweetness units? Sweeteners are still caloric, the
point is that they provide the same sweetness for less calories.

------
WesleyRourke
Raised insulin levels are much more complicated than we once thought. You can
get an insulin response from artificial sweeteners just swished in your mouth
and spat out. Solution, eat real food when you can

~~~
3rd3
Do you have a source for that? The last time I checked this worked with mice,
but humans showed no insulin response from sweet taste alone.

~~~
BSousa
I don't right now, but from my times when competing, I used to read a lot of
science based research on nutrition and there was a study that said swishing a
carb rich liquid was enough to trigger it.

I think I first saw it referenced on an old edition of 'The Complete Guide to
Sports Nutrition' by Anita Bean

~~~
demallien
Artificial sweeteners are not "carb rich". That's kind of the point of them...

~~~
BSousa
What I meant was there is a possibility of it happening as a sweet taste
(parent didn't mention sweeteners, just sweet taste) response since there is a
similar response to carb rich drinks (study didn't mention the kind of carbs
so no idea)

------
devindotcom
Doesn't seem so strange - if you create a sugar deficit in your body by
significantly reducing your intake, wouldn't you expect the body to be more
responsive to sugars when it encounters them?

~~~
mark-r
I believe that's why they had a control group with unsweetened water.

------
dbbolton
Now let's see a human study where people who consume those sweeteners, eat
carbohydrates in moderation, and exercise regularly are still at increased
risk for diabetes.

------
Dirlewanger
"metabolic abnormalities"

Anyone know if they go into these into the paper? Really want to know what
else is in the paper; I chew way too much sugar-free gum.

~~~
spmurrayzzz
Most sugar-free gum uses some type of sugar alcohol (e.g. xylitol,
erythritol). These are not technically-speaking considering NAS. Their
mechanisms of absorption vary wildly and, while in some cases they can cause
digestive stress in large amounts, there is no good evidence AFAIK that they
have a deleterious effect on gut microbiota.

------
coldcode
People rarely consider how what you eat affects your microflora which then
affects various other systems and may even affect your desire to consume.

~~~
viewer5
Without delving into a bunch of scientific papers, how could I go about
considering how my dietary choices influence my microflora for better or
worse?

~~~
tormeh
Well, you can't really do that. We don't know nearly enough about it. Hell,
we're not even good at normal dietary science yet and the whole gut bacteria
science field is really new.

You can find a healthy and fit person and get them to give you some of their
gut flora and then eat it. That could probably work. It also might make you
sick (I imagine) and it's terribly disgusting: "On a scale from swallowed to
poo, how do you want my eaten food?"

~~~
dasil003
I don't think that would work (bacteria living the colon can not necessarily
survive all the way through the digestive tract). What _is_ an accepted form
of gut biome therapy is a stool transplant:

[http://en.wikipedia.org/wiki/Fecal_bacteriotherapy](http://en.wikipedia.org/wiki/Fecal_bacteriotherapy)

~~~
tormeh
Could it work if put in capsules dissolving in the right stage? Anyway, thanks
for the link.

------
louwrentius
The maximum dose is quite high, but does the effect also occurs when consuming
more sane dosage a day?

------
tokenadult
I'm paywalled out of seeing the whole article until I try a workaround (after
which I may expand this comment), but I think we can all see the abstract of
the article if we follow the link kindly submitted here. Yet some questions in
other comments raise issues that are already responded to by the article
abstract. Here is the full text of the article abstract available in the free
view at the link:

"Non-caloric artificial sweeteners (NAS) are among the most widely used food
additives worldwide, regularly consumed by lean and obese individuals alike.
NAS consumption is considered safe and beneficial owing to their low caloric
content, yet supporting scientific data remain sparse and controversial. Here
we demonstrate that consumption of commonly used NAS formulations drives the
development of glucose intolerance through induction of compositional and
functional alterations to the intestinal microbiota. These NAS-mediated
deleterious metabolic effects are abrogated by antibiotic treatment, and are
fully transferrable to germ-free mice upon faecal transplantation of
microbiota configurations from NAS-consuming mice, or of microbiota
anaerobically incubated in the presence of NAS. We identify NAS-altered
microbial metabolic pathways that are linked to host susceptibility to
metabolic disease, and demonstrate similar NAS-induced dysbiosis and glucose
intolerance in healthy human subjects. Collectively, our results link NAS
consumption, dysbiosis and metabolic abnormalities, thereby calling for a
reassessment of massive NAS usage."

AFTER EDIT: After reading all the comments in this thread to the time of this
edit, I see that some participants here disagree entirely with how I commented
at first (as above). I note their opinion with interest and say here for the
record simply that I saw previous comments that raised questions about
information that is available in the article abstract for all of us to read. I
meanwhile did find my workaround to get the full text of the article (I have
library access with journal subscriptions for one aspect of my work, which is
rather slow and buggy) and from the full article text I see that the
experimental approach the researchers tried--feeding mice with the artificial
sweetener to see if that changed gut microbiota in the mice, and then
transferring the gut microbiota to other mice--did indeed bring about clinical
signs consistent with the idea that the sweetener itself might cause related
clinical signs in human beings.

"To test whether the microbiota role is causal, we performed faecal
transplantation experiments, by transferring the microbiota configuration from
mice on normal-chow diet drinking commercial saccharin or glucose (control)
into normal-chow-consuming germ-free mice (Extended Data Fig. 1e). Notably,
recipients of microbiota from mice consuming commercial saccharin exhibited
impaired glucose tolerance as compared to control (glucose) microbiota
recipients, determined 6 days following transfer (P < 0.03, Fig. 1e and
Extended Data Fig. 2e). Transferring the microbiota composition of HFD-
consuming mice drinking water or pure saccharin replicated the glucose
intolerance phenotype (P < 0.004, Fig. 1f and Extended Data Fig. 2f).
Together, these results establish that the metabolic derangements induced by
NAS consumption are mediated by the intestinal microbiota."

This preliminary finding, which of course needs to be replicated, has caused
alarm in the industry, according to the link participant nostromo kindly
shared in this thread.[1] There is epidemiological signal that human beings
who consume a lot of artificial sweeteners are not especially healthy people
compared to people who consume few. Teasing out the mechanism that may underly
that observational finding will take more research, but this is important
research to get right.

"To study the functional consequences of NAS consumption, we performed shotgun
metagenomic sequencing of faecal samples from before and after 11 weeks of
commercial saccharin consumption, compared to control mice consuming either
glucose or water. To compare relative species abundance, we mapped sequencing
reads to the human microbiome project reference genome database16. In
agreement with the 16S rRNA analysis, saccharin treatment induced the largest
changes in microbial relative species abundance (Fig. 2a, Supplementary Table
2; F-test P value < 10−10). These changes are unlikely to be an artefact of
horizontal gene transfer or poorly covered genomes, because changes in
relative abundance were observed across much of the length of the bacterial
genomes, as exemplified by one overrepresented (Bacteroides vulgatus, Extended
Data Fig. 7a) and one underrepresented species (Akkermansia muciniphila,
Extended Data Fig. 7b)."

The authors sum up their experimental findings by writing

"In summary, our results suggest that NAS consumption in both mice and humans
enhances the risk of glucose intolerance and that these adverse metabolic
effects are mediated by modulation of the composition and function of the
microbiota. Notably, several of the bacterial taxa that changed following NAS
consumption were previously associated with type 2 diabetes in humans13, 20,
including over-representation of Bacteroides and under-representation of
Clostridiales. Both Gram-positive and Gram-negative taxa contributed to the
NAS-induced phenotype (Fig. 1a, b) and were enriched for glycan degradation
pathways (Extended Data Fig. 6), previously linked to enhanced energy harvest
(Fig. 2c, d)11, 24. This suggests that elaborate inter-species microbial
cooperation may functionally orchestrate the gut ecosystem and contribute to
vital community activities in diverging environmental conditions (for example,
normal-chow versus high-fat dietary conditions). In addition, we show that
metagenomes of saccharin-consuming mice are enriched with multiple additional
pathways previously shown to associate with diabetes mellitus23 or obesity11
in mice and humans, including sphingolipid metabolism and lipopolysaccharide
biosynthesis25."

There have been a lot of questions raised in this thread, and indeed the
article itself raises plenty of interesting questions to follow up with
further research. When discussing a new preliminary research finding like
this, we can work outward from the article abstract to news reports about the
article findings to the article text itself to focus on the known issues and
define clearly the unknown issues. I appreciate comments from anyone here
about how I can help contribute to more informed and thoughtful, in Hacker
News sense of "thoughtful,"[2] discussion of research on human nutrition.

Other comments here asked why we should respect journal paywalls at all, and
the basic answer to that question is a basic principle of economics, that
people respond to incentives. (That's the same reason you don't found a
startup that you expect will always lose money for all time.) _Nature_ is one
of the most-cited scientific journals in the world, so it's a big coup to be
published there, and that means _Nature_ gets a lot of submissions. To slog
through all the submissions with adequate editorial work does cost money. (I
used to be a junior editor of an academic journal.) The article gets more
attention (it has received a lot of attention in this thread) if it is in a
better rather than worse journal. Some journals are lousy enough to publish
anything, and those journals beg for submissions, but _Nature_ can charge for
subscriptions and impose paywalls (which expire for government-funded
research, with author sharing of author manuscripts on free sites usually
being mandatory after a year embargo) because what it publishes is often worth
reading (as here).

AFTER ONE MORE EDIT:

I see that while I was reading the fine article from _Nature_ submitted to
open a thread, my comment is now part of a thread that is about the _New
Scientist_ popular article on the same research finding. This will be
confusing to readers newly visiting this thread. The title of the _Nature_
article is "Artificial sweeteners induce glucose intolerance by altering the
gut microbiota" (the Hacker News thread title I saw, per the usual rule of
using the article headline as the submission headline) and the article DOI is

10.1038/nature13793

for the full article published online (behind a paywall) on 17 September 2014.

[1]
[http://www.newscientist.com/article/mg22329872.600-artificia...](http://www.newscientist.com/article/mg22329872.600-artificial-
sweeteners-linked-to-glucose-intolerance.html)

[2] "The most important principle on HN, though, is to make thoughtful
comments. Thoughtful in both senses: both civil and substantial."

[https://news.ycombinator.com/newswelcome.html](https://news.ycombinator.com/newswelcome.html)

~~~
pash
I meant to downvote your comment but accidentally upvoted it.

You wrote that you have nothing meaningful to say and quoted the abstract,
contributing nothing to the conversation. Next time, instead of using your
accumulated karma to monopolize the top spot while saying nothing, just say
nothing.

~~~
zaroth
> instead of using your accumulated karma to monopolize the top spot

You only get to the top spot in a comment section by getting _that specific
comment_ upvoted there.

... at least, that's certainly how I would expect it to work! If the site
gives preference to comments based on preexisting karma, at least after any
upvotes have been cast, then that would be highly disappointing.

~~~
makomk
The site gives preference to comments based on preexisting karma, especially
shortly after they're posted.

------
Someone1234
So the public funds studies, which they give to journals for free, who then
sell access for $3.99/view. I'm really not sure this was the "free exchange of
ideas" which science is based upon.

Even the New York times only charges $3.75/week (the nature price is per
article/view NOT per week, it would be $4.14 if their $199 plan was weekly)
and the NYT has to actually pay journalists to create the content. Nature gets
all their content for free.

So what are Nature's expenses anyway? They no longer have to type set as it is
just an identical PDF which is sent to them. Is hosting and management of the
web-site really so costly that it is $3.99/article?

~~~
yincrash
The peer review process, I would think.

~~~
Someone1234
They don't pay for people to peer review as far as I know.

~~~
dragonwriter
That the individual peer reviewers aren't paid does not imply that
coordinating the peer review process is cost-free to the publication.

------
jimhefferon
Diet soda makes you fat.

------
kolev
Sweeteners are suspected to have downed the Roman empire (via lead poisoning),
so, learn from history and just change your taste norm and you'll live longer
and happier. I had a sweet tooth once and it took about a couple of years to
even not being able to tolerate it. The weak find excuses, the strong adapt
and improve. Just reject anything with refined sugar or fancy new "healthier"
sweeteners - do you like sugar more than tomorrow? Cane sugar is not healthier
than HCFS (it might be just slightly less harmful). Agave "Nectar" actually
has significantly more fructose than HCFS... and it's not unprocessed as
claimed, and so on. Stevia is slightly different, the plant has other
benefits, but I wouldn't ever use the adulterated version (Reb A or whatever).
Hack your taste buds, hackers!

~~~
kolev
Sugar alcohols (xylitol, sorbitol, maltitol, mannitol, erythritol) have the
same negative effect on the gut microbiota.

