Excess body fat and obesity are an immune response to gram-negative gut bacteria, not a metabolic problem. Fix it by taking oral polymyxin, or a comparable antibiotic.
So they’ve established very firmly that gut bacteria are sufficient to cause excess body fat, but whether that’s the main source in the general human population is unknown.
Quack quack goes the duck. I wouldn’t use such an experimental treatment even on your pet rat.
(It does sound vaguely promising, like thousands of other candidate substances in translational medicine that didn’t pan out.)
Edit: The paper is not from the journal Nature, it is instead from a different journal which is also published by the same company. The paper was published in The ISME Journal, with an impact factor of 7.4, compared to Nature’s impact factor of 31! So next time, please do your research.
The paper is open access, but your link is blocked unless entered directly (they probably don’t accept any non-site values for the HTTP referer field). This link should work.
Also, before you start taking antibiotics, here’s the relevant part from that abstract:
The obesity-inducing capacity of this human-derived endotoxin producer in gnotobiotic mice suggests that it may causatively contribute to the development of obesity in its human host.
No mention of using antibiotics, polymyxin isn’t mentioned once. As for the second study, there are reasons you don’t administer polymyxin intravenously, and its intravenous efficacy is much different from when taken orally.
the effect sizes were huge in both experiments.
No, there were no antibiotics used in the ISMEJ article: ” The volunteer lost 30.1 kg after 9 weeks, and 51.4 kg after 23 weeks, on a diet composed of whole grains, traditional Chinese medicinal foods and prebiotics (WTP diet, Supplementary Information; Supplementary Figure 1)”
So, it’s reasonable to suspect that polymyxin would fix most human obesity too.
Thanks for pointing out the journal error, that has been corrected. Also big thanks for the working link.
The “experiment” with the human subject in the ISMEJ article was stupid, which was why I didn’t mention it. Everything I’m saying is based on the mouse experiments.
I do think your interpretation of these experiments is way too restricted. In a frequentist sense, everything you’re saying is reasonable, since we don’t know how well various results generalize (mouse to human, intravenous to oral, etc...). But in a Bayesian sense, this is pretty good evidence. I guessed that polymyxin would reduce body fat (regardless of how it’s administered) just based on reading the ISMEJ article, which never mentioned antibiotics. That means the first article alone was enough to promote the hypothesis out of entropy. I then found the second article by searching for papers discussing polymyxin and obesity, and the result was what I expected (large drop in fat after polymyxin administration), so that’s a big evidential boost in favor.
Neither of those gives evidence for the mouse result generalizing to humans. However, we do know that gram-negative bacteria are pretty ubiquitous and do trigger an immune response in humans similar to that in mice, so based on the physical systems we should expect a similar response to antibiotics.
There was a special issue of Nature focusing on human microbiota a few months back which seems to have a lot more relevant research with humans, but I haven’t had time to go through them in depth yet (which is why this was a poorly-researched comment rather than a full discussion post).
Ah, but the cool thing is that you don’t need an experimental treatment. We’re talking bog-standard antibiotics, nothing unusual. The only unusual thing is what you’d be trying to do with those antibiotics.
And unlike the usual vaguely promising substances, the effect sizes were huge in both experiments. You don’t get a 46% drop in adipose fat from random noise.
Quack quack goes the duck. I wouldn’t use such an experimental treatment even on your pet rat.
(It does sound vaguely promising, like thousands of other candidate substances in translational medicine that didn’t pan out.)
Edit: The paper is not from the journal Nature, it is instead from a different journal which is also published by the same company. The paper was published in The ISME Journal, with an impact factor of 7.4, compared to Nature’s impact factor of 31! So next time, please do your research.
The paper is open access, but your link is blocked unless entered directly (they probably don’t accept any non-site values for the HTTP referer field). This link should work.
Also, before you start taking antibiotics, here’s the relevant part from that abstract:
No mention of using antibiotics, polymyxin isn’t mentioned once. As for the second study, there are reasons you don’t administer polymyxin intravenously, and its intravenous efficacy is much different from when taken orally.
No, there were no antibiotics used in the ISMEJ article: ” The volunteer lost 30.1 kg after 9 weeks, and 51.4 kg after 23 weeks, on a diet composed of whole grains, traditional Chinese medicinal foods and prebiotics (WTP diet, Supplementary Information; Supplementary Figure 1)”
No.
Thanks for pointing out the journal error, that has been corrected. Also big thanks for the working link.
The “experiment” with the human subject in the ISMEJ article was stupid, which was why I didn’t mention it. Everything I’m saying is based on the mouse experiments.
I do think your interpretation of these experiments is way too restricted. In a frequentist sense, everything you’re saying is reasonable, since we don’t know how well various results generalize (mouse to human, intravenous to oral, etc...). But in a Bayesian sense, this is pretty good evidence. I guessed that polymyxin would reduce body fat (regardless of how it’s administered) just based on reading the ISMEJ article, which never mentioned antibiotics. That means the first article alone was enough to promote the hypothesis out of entropy. I then found the second article by searching for papers discussing polymyxin and obesity, and the result was what I expected (large drop in fat after polymyxin administration), so that’s a big evidential boost in favor.
Neither of those gives evidence for the mouse result generalizing to humans. However, we do know that gram-negative bacteria are pretty ubiquitous and do trigger an immune response in humans similar to that in mice, so based on the physical systems we should expect a similar response to antibiotics.
There was a special issue of Nature focusing on human microbiota a few months back which seems to have a lot more relevant research with humans, but I haven’t had time to go through them in depth yet (which is why this was a poorly-researched comment rather than a full discussion post).
Ah, but the cool thing is that you don’t need an experimental treatment. We’re talking bog-standard antibiotics, nothing unusual. The only unusual thing is what you’d be trying to do with those antibiotics.
And unlike the usual vaguely promising substances, the effect sizes were huge in both experiments. You don’t get a 46% drop in adipose fat from random noise.