Other Why some feces float and others sink - some bacteria produce more gas than others (Oct 2022, mice) Genesis of fecal floatation is causally linked to gut microbial colonization in mice

Michael Harrop

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https://phys.org/news/2022-11-feces.html
https://www.nature.com/articles/s41598-022-22626-x

Someone asked about this in another thread, so I'm posting this study since it hasn't been posted here before.

That suggested that floating fecal matter was related to the makeup of the gut microbiome. The researchers then collected stool samples from healthy mice that were not part of the original study, but who produced floaters, and injected the material into the guts of the sterile mice. They found that all of the test mice began producing floaters. This, the researchers contend, suggests that the reason some fecal matter floats is due to the nature of the bacteria in the gut—some produce more gas than others.

The researchers were not able to isolate the bacteria that produced more gas, but did note that Bacteroides ovatus has previously been found to produce more flatulence in human patients. Logic suggests it is likely one of the culprits responsible for the formation of floaters in humans, and perhaps in lab mice. The team suggests more work will need to be done to confirm their suspicions and to find other bacteria involved in producing more gas, and thus floaters.

Abstract​

The origin of fecal floatation phenomenon remains poorly understood. Following our serendipitous discovery of differences in buoyancy of feces from germ-free and conventional mice, we characterized microbial and physical properties of feces from germ-free and gut-colonized (conventional and conventionalized) mice. The gut-colonization associated differences were assessed in feces using DNA, bacterial-PCR, scanning electron microscopy, FACS, thermogravimetry and pycnometry.

Based on the differences in buoyancy of feces, we developed levô in fimo test (LIFT) to distinguish sinking feces (sinkers) of germ-free mice from floating feces (floaters) of gut-colonized mice. By simultaneous tracking of microbiota densities and gut colonization kinetics in fecal transplanted mice, we provide first direct evidence of causal relationship between gut microbial colonization and fecal floatation.

Rare discordance in LIFT and microbiota density indicated that enrichment of gasogenic gut colonizers may be necessary for fecal floatation. Finally, fecal metagenomics analysis of ‘floaters’ from conventional and syngeneic fecal transplanted mice identified colonization of > 10 gasogenic bacterial species including highly prevalent B. ovatus, an anaerobic commensal bacteria linked with flatulence and intestinal bowel diseases.

The findings reported here will improve our understanding of food microbial biotransformation and gut microbial regulators of fecal floatation in human health and disease.
 
Format correct?
  1. Yes
That backronym LIFT is funny, I wonder what it actually means...


Though you have to give it to these researchers for studying a topic that is likely to get them laughed at when they present at conferences. It doesn't exactly have disease relevance...
 
It doesn't exactly have disease relevance...
Not so! Here's a recent thread displaying the popular notion that floating stools are unhealthy due to them containing undigested fats. This study indicates that's not the case. There may also be use in regards to IBS.

This reminds me of a perfectly valid and useful paper that concluded that women with endometriosis were more attractive. Here's an example of how such a thing is useful: Attractiveness, facial features, health & development, and FMT donor selection. (Jul 2019). But some people complained that a study dared to categorize women for their attractiveness and it was retracted for that reason.

With science and knowledge, everything is useful.
 
That's interesting. I wonder if probiotics woukd fix this problem with the floaters. I have been always told that a high fat diet could do this. Thanks for sharing.
 
Very Interesting and informative I have always heard this would happen due to lack of fiber in diet.
In my case if i eat more fiber i suffer soft stool or diarrhoea and statorrhoea. It's not just fibre, though, but other factors.

Ideally, human studies would be ideal, we don't have the same microbiome as rats.
But in other paper say this:
Feces of more than ten percent of healthy individuals consistently float and this is not linked to any specific pathology1. Notably, one out of four patients with functional bowel disorder experience fecal floatation2.

SO YES if the poop float can be dangerous in some cases.
 
other paper say this
Your first link:
Floating Stools — Flatus versus Fat (1972) https://www.nejm.org/doi/abs/10.1056/NEJM197205042861804

All floating stools sank when their gas volume was compressed by positive pressure. Thus, to float, stools must contain gas.

indicating that the floating or sinking propensity of such stools depends upon differences in gas rather than fat content

The second link is an association. It does not conclude that floating stools are dangerous.
 
Your first link:
Floating Stools — Flatus versus Fat (1972) https://www.nejm.org/doi/abs/10.1056/NEJM197205042861804



The second link is an association. It does not conclude that floating stools are dangerous.
Quote
"In a healthy adult, the endogenous microbially produced gut gases (hydrogen, methane, and insignificant quantities of odorogenic sulfides and ammonia) are only a minor amount as opposed to bulk of gases, predominantly oxygen, nitrogen, and carbon dioxide, generated every day from exogenous air that enter GI tract during ingestion of food and water"

If you have elevated methane or hydrogen or sulphur, you have SIBO, that's not healthy, it's the opposite.
That's why I prefer to go to something safer and rule out someone whose stool floats (of course it depends on other factors as well).
 
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