In one way or another, they escape
Farts are always a cause of embarrassment when we are in public places, especially narrow and full of people. The fear of being caught may make you feel ashamed. So, it’s more polite to hold them in when we are with other strangers. At most, only friends may tolerate farting as a joke.
Not everybody knows that farting is a symptom of a healthy and working good intestine. According to the University of Newcastle, holding in gas can make them pass through your gut wall and get reabsorbed into your circulation. Then they can be released, whether you like it or not, but from your mouth.
A few brave scientists have investigated the phenomenon of flatulence. In one study, 10 healthy volunteers were fed half a can of baked beans in addition to their regular diets and given a rectal catheter to measure their farts over a 24-hour period. The results were that men and women released the same amount of gas, and the average number of ‘flatus episodes’ (a single fart, or series of farts) was 8. Another study of 10 people found that high-fiber diets led to fewer but bigger farts, and a third study found that gases containing sulfur are responsible for the world’s stinkiest farts. Moreover, 2 judges were tapped to rate the odor intensity of each emission.
Scientific literature also seems to suggest expelling gas. In specific, a 2010 paper on “Methane and the gastrointestinal tract” says methane, hydrogen sulfide, and other gases produced in the intestinal tract are mostly eliminated from the anus or expelled from ‘lungs’. So, holding in farts may cause belching, flatulence, bloating and pain, but in some severe cases, pouches can form along the wall of the colon and get infected causing diverticulitis.
Source mentalfloss.com