Flatulence, commonly referred to as “farting,” is caused by the presence of a gas mixture known as flatus, which is produced by symbiotic bacteria and yeasts living in the gastrointestinal tract. Flatus is initially generated by swallowed air, digestion, high-fiber foods and the by-products of intestinal bacteria. Some digestive system disorders, such as irritable bowel syndrome, can also produce excess gas.
Ordinarily, the intestines produce between 500 and 2,000 mls of gas, which is released under pressure from the anus at regular intervals. The average human releases 0.5 to 1.5 liters of flatus a day by flatulating 12 to 25 times. The varying smells depend on the ratio of gases- nitrogen, carbon dioxide, hydrogen, methane, and oxygen-which is influenced by the foods we eat. Intestinal gas is composed of 90% exogenous sources-air that is ingested through the nose and mouth, and 10% endogenous sources-gas produced within the digestive tract. The exogenous gases are swallowed when eating or drinking. The endogenous gases are produced as a by-product of digesting certain types of foods, especially those high in polysaccharides.
The foul odor results from the presence of specific fatty acids such as butyric acid (rancid butter smell), reduced sulfur compounds such as hydrogen sulfide (rotten egg smell), and carbonyl sulfide that are the result of protein breakdown. Flatulence odor can also occur when there are a number of bacteria and feces in the anus while being expelled.
Flatus is brought to the anus in the same peristalsis method as feces, causing a similar feeling of urgency and discomfort. Nerve endings in the rectum learn to distinguish between flatus and feces, although loose stool can confuse these nerves, and sometimes result in accidental defecation.
The noises commonly associated with flatulence are caused by the vibration of the anal opening. The sound varies depending on the tightness of the sphincter muscle and velocity of the gas being propelled, as well as other factors such as moisture and body fat. The pitch of the flatulence outburst can also be affected by the anal embouchure (anal “wind”).
Any way you pass it; excessive flatulence is no fun. Flatulence can cause social embarrassment, discomfort, and pain when accompanied by intestinal bloating.
Digestive enzyme supplements can significantly reduce the amount of flatulence that is caused by food components not digested by the body.