How does life arise? Are we alone in the universe? Why does poop sometimes float and sometimes sink? These questions keep us awake at night, but worry no more we finally have the answer to the last one and by accident.
For many years, it has been a mystery why sometimes poop floats while at other times it sinks. Some theories have suggested that a higher fat content in the stool may result in increased buoyancy, leading to the formation of floating stool.
However, in a 1972 study published in The New England Journal of Medicine When they examined the stool of 33 healthy subjects (nine with floating stools, 24 with sinking stools and six patients with fatty stools), they found that all the floating shit sank when the gas within their stool was “compressed by positive pressure” (stool crushing).
“After degassing, previously floating and sinking feces had similar specific gravities, indicating that the propensity of poop to float or sink depends on differences in gas content rather than fat content,” the team wrote.
While interesting, all this does not really explain the cause behind the difference in gas and water content. Recently, a team studying mice that were germ-free noticed something unusual in their feces. While approximately 10% of healthy humans consistently produce floating feces, this percentage is much higher in mice, around 50%. The team, which published their work in Scientific Reports, observed that the feces of the germ-free mice tended to sink.
“Our chance finding of ‘sinking’ and ‘floating’ feces in Trump phosphate-binding solution (TFS) in germ-colonized and germ-free mice, respectively, led to the question of whether intestinal colonizers were fundamentally linked to the genesis of the fecal flotation phenomenon,” the team wrote in their study.
Further research revealed that the team could induce floating feces by transplanting intestinal bacteria from healthy mice into the stomach of germ-free mice. “By introducing microorganisms into the gut of germ-free mice, we have conclusively demonstrated that colonization of the gut microbiome is a prerequisite for floating feces,” the researchers wrote.
“By introducing microorganisms into the gut of germ-free mice, we have conclusively demonstrated that colonization of the gut microbiome is a prerequisite for floating feces.”
Nevertheless, the researchers emphasize that more study is needed to determine which intestinal bacteria cause the flotation and to analyze human poop. However, they identified several bacterial species associated with floating feces. “In fact, we identified Bacteroides ovatus as the most enriched species in our analysis, which has been positively correlated with flatulence and anal gas evacuation in human patients. In addition, we also identified Bacteroides fragilis, which is known to produce hydrogen gas in the gut.”
This study was published in Scientific Reports.
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