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...

[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