The science of why some poops float

No topic has escaped the scrutiny of science. The same holds true for the buoyancy of our poop. But no worries; the answer should be at hand now.

For decades, researchers have been trying to figure out why some people’s poop floats and others’ sinks in a toilet bowl filled with water. Around 15% of the total population is included in the first category. There has been a theory concerning the relationship between the gas concentration of digestive contents and their buoyant qualities since at least 1972.

This was formerly thought to be caused by a high amount of fat in the feces. In a study published in “Scientific Reports,” researchers led by Nagarajan Kannan of the Mayo Clinic in Rochester suggest that the gas-based assumption regarding the floating poop may in fact be correct.

Gas-producing bacterias

They found that excrement from germ-free mice always settled to the bottom of the tank. While half of the conspecifics with a typical microbiome also had feces that floated to the surface, the other half did not. Researchers were intrigued by this and decided to infect the germ-free mice with gut microbes from regular mice and two young females. Consequently, these animals had feces that were more buoyant.

There is now conclusive evidence that gas produced by intestinal microorganisms, as opposed to unswallowed air or other factors, is responsible for the flotation of poop. Examining the floating poop more closely revealed that it was full of gas-producing bacteria like Bacteroides ovatus and Bacteroides uniformis.

Humans produce more methane and have more farts as a result of both of these factors. However, it is still unclear how much gas is produced by the various microorganisms, and hence which organism is the primary cause of the expansion.

It is also not apparent, according to the experts, whether or not the floating poop can provide insight into people’s overall gut health. Diet, environmental factors, and even a person’s way of birth all play a role in shaping their unique gut flora. All these considerations are essential for a proper analysis.

The 1972 research

A discussion between gastroenterologist Michael Levitt of the University of Minnesota Hospitals and his student William Duane, who mentioned that his stools would always float, was the genesis of the 1972 theory. A little while later, Duane brought in a feces sample, which the two scientists quickly compressed and then dropped into the water.

They sampled 33 people and found that 9 of them had stools that floated. The poop again sank when Levitt and Duane released the gas in it. At the time, scientists had a sneaking suspicion that an imbalance in the gut bacteria was to blame for the floating poop, since two samples showed very high methane levels that could only have been caused by improper digestion of carbon-rich food. Here it is, ladies and gentlemen, the science behind the floating and sinking poop.

By Bertie Atkinson

Bertie Atkinson is a history writer at Malevus. He writes about diverse subjects in history, from ancient civilizations to world wars. In his free time, he enjoys reading, watching Netflix, and playing chess.