Flatulence
From Wikipedia, the free encyclopedia:Flatulence (expelled from humans through a processes commonly known as 'farting' or 'emitting gas') is the presence of a mixture of gases known as flatus in the digestive tract of mammals.
Explanation
Flatus is expelled under pressure through the anus, whereby, as a result of the voluntary or involuntary tensing of the anal sphincter, the rapid evacuation of gases from the lower intestine occurs. Depending upon the relative state of the sphincter (relaxed/tense) or the positioning of each buttock, this generally results in an audible crackling or trumpeting sound. This is often perceived as being humorous or socially awkward. The process may also result in a relatively silent and slow emission of odor, often deemed foul in character, resulting from the sensation of olfactory components such as skatole, indole, and sulfurous compounds.
Social considerations
While the act of farting is generally considered to be an unfortunate (but sometimes intentionally contrived) occurence in public settings, a flatus may, in casual circumstances, be used as either a humorous supplement to a joke, or as a comic activity in and of itself. Usually accompanied by a distinct odor and sound, a process known informally as farting, or as passing gas. The non-odorous gases are mainly nitrogen (ingested), carbon dioxide (produced by aerobic microbes or ingested), and hydrogen (produced by some microbes and consumed by others), as well as lesser amounts of oxygen (ingested) and methane (produced by anaerobic microbes). Odors result from trace amounts of other components (often containing sulfur compounds, see below).
Composition of flatus gases
Nitrogen is the primary gas released. Methane and hydrogen, lesser components, are flammable, and so flatus is susceptible to catching fire. Not all humans produce flatus that contains methane. For example, in one study of the feces of nine adults, only five of the samples contained bacteria capable of producing methane. Similar results are found in samples of gas obtained from within the rectum.
The gas released during a flatus event frequently has a foul odor which mainly results from low molecular weight fatty acids such as butyric acid (rancid butter smell) and reduced sulfur compounds such as hydrogen sulfide (rotten egg smell) and carbonyl sulfide that are the result of protein breakdown. The incidence of odoriferous compounds in flatus increases from herbivores, such as cattle, through omnivores to carnivorous species, such as cats. Flatulence odor can also occur when there is a number of bacteria and/or feces in the anus.
Mechanism of action
The noises commonly associated with flatulence are caused by the vibration of the anal sphincter, not by the buttocks. 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 water and body fat. The pitch of the flatulence outburst can also be affected by the anal embouchure. Among humans, sometimes farting happens accidentally, such as incidentally to coughing or sneezing; on other occasions, intentional farting occurs through the tensing and releasing of the anal sphincter. Humans are also known to flatulate during sleep, largely due to the relaxed state of body muscles, which results in the average person flatulating about 20-60 times through any given night.[citation needed]
Flatus is brought to the rectum 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 results in accidental defecation.
Causes of flatus odor
Intestinal gas is composed of varying quantities of exogenous sources (air that is ingested through the nose and mouth) and endogenous sources (gas produced within the digestive tract). The exogenous gases are swallowed (aerophagia) when eating or drinking or during times of excessive salivation (as might occur when nauseated or as the result of gastroesophageal reflux disease). The endogenous gases are produced as a by-product of digesting certain types of food. Anything that causes food to be incompletely digested in the small intestine may cause flatulence when the material arrives in the large intestine due to fermentation, particularly if yeast organisms are present.
Flatulence producing foods are typically high in polysaccharides (especially oligosaccharides such as inulin) and include beans, lentils, milk, onions, radishes, sweet potatoes, cheese, cashews, broccoli, cabbage, Jerusalem artichokes, oats, yeast in breads, etc. In beans, endogenous gases seem to arise from oligosaccharides, carbohydrates that are resistant to digestion. These pass through the upper intestine largely unchanged, and when they reach the lower intestine, bacteria feed on them, producing copious amounts of flatus. In the case of those with lactose intolerance, intestinal bacteria feeding on lactose can give rise to excessive gas production when milk or lactose-containing substances have been consumed.
Interest in the causes of flatulence was spurred by high-altitude flight and the space program; the low atmospheric pressure, confined conditions, and stresses peculiar to those endeavours were cause for concern.
Remedies
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Dietary
Certain spices counteract the production of intestinal gas, most notably cumin[citation needed], coriander[citation needed], caraway and the closely related ajwain, turmeric, asafoetida (hing), epazote, and kombu kelp (a Japanese seaweed). Many people report that by reducing intake of most refined carbohydrates (such as rice, pasta, potatoes and bread), the amount of flatulence may decrease significantly. The water-soluble oligosaccharides in beans that contribute to production of intestinal gas can be reduced through a regime of brief boiling followed by a long period of soaking, but at a cost of also leaching out other water-soluble nutrients. Also, gas can be reduced by fermenting the beans, and making them less gas-inducing, by cooking them in the liquor from a previous batch. Lactobacillus casei and Lactobacillus plantarum have recently been proven responsible for this effect. Some legumes also stand up to prolonged cooking, which can help break down the oligosaccharides into simple sugars. Fermentation also breaks down oligosaccharides, which is why fermented bean products such as miso and tofu are less likely to produce as much intestinal gas.
Probiotics (yogurt, kefir, etc.) often reduce flatulence when they are used to restore balance to the normal intestinal flora. Yogurt contains Lactobacillus acidophilus which is a good bacteria to fight flatulence. L. Acidophilus makes the intestines more acidic so it maintains the natural balance of fermentation processes. Acidophilus is available in supplements (non-dairy is best). Prebiotics, which generally are non-digestible oligosaccharides, such as fructooligosaccharide, generally increase flatulence in a similar way as described for lactose intolerance.
Medicinal activated charcoal tablets have also been reported as effective in reducing both odor and quantity of flatus when taken immediately before food that is likely to cause flatulence later.
Pharmacological
Digestive enzyme supplements can significantly reduce the amount of flatulence that is caused by some components of foods not being digested by the body and feeding the microbes in the small and large intestines. It has been shown that alpha-galactosidase enzymes, which can digest complex sugars, are effective in reducing the volume and frequency of flatus. The enzymes alpha-galactosidase (brands Beano, Bean-zyme), lactase (brand Lactaid), amylase, lipase, protease, cellulase, glucoamylase, invertase, malt diastase, pectinase, and bromelain are available, either individually or in combination blends, in commercial products.
The antibiotic rifaximin, often used to treat diarrhea caused by the microorganism E. coli, has been shown to reduce both the production of intestinal gas and the frequency of flatus events.
While not affecting the production of the gases themselves, surfactants (agents which lower surface tension) can reduce the disagreeable sensations associated with flatulence, by aiding the dissolution of the gases into liquid and solid fecal matter. Preparations containing simethicone operate by promoting the coalescence of smaller bubbles into larger ones more easily passed from the body. They do not decrease the total amount of gas generated or passed from the colon.
Often it is helpful to ingest small quantities of acidic liquids with meals, such as lemon juice or vinegar, to stimulate the production of hydrochloric acid, which in turn increases enzyme production. This facilitates digestion and may limit gas production.
Odor from flatulence, caused by bacteria in the bowel, can be treated by taking bismuth subgallate (brand Devrom). Commonly used by individuals who have had ostomy surgery, bariatric surgery, fecal incontinence and irritable bowel syndrome.
Health effects
As a normal body function, the action of flatulence is an important signal of normal bowel activity and hence is often documented by nursing staff following surgical or other treatment of patients. However, symptoms of excessive flatulence can indicate the presence of irritable bowel syndrome or some other organic disease. In particular, the sudden occurrence of excessive flatulence together with the onset of new symptoms provide reason for seeking further medical examination.
Flatulence is not poisonous; it is a natural component of various intestinal contents. However, discomfort may develop from the build-up of gas pressure. In theory, pathological distension of the bowel, leading to constipation, could result if a person holds in flatus.
Not all flatus is released from the body via the anus. When the partial pressure of any gas component of the intestinal lumen is higher than its partial pressure in the blood, that component enters into the bloodstream of the intestinal wall by the process of diffusion. As the blood passes through the lungs this gas can diffuse back out of the blood and be exhaled. If a person holds in flatus during daytime, it will often be released during sleep when the body is relaxed. Some flatus can become trapped within the feces during its compaction and will exit the body, still contained within the fecal matter, during the process of defecation.
Recording flatulence events
The term meteorism is defined as the presence of gas within the abdomen or intestines. However, it is sometimes also used to describe the condition of excessive flatulence. Since subjective judgments vary considerably about what constitutes normal and elevated levels of flatulence, medical personnel sometimes instruct a patient complaining about excessive flatulence to maintain a personal flatulence diary. Researchers studying flatulence have also developed what is called a flatulogram. Its horizontal axis represents time (typically 24 hours, with each hour being marked on the time line). The subject is instructed to make a pencil mark on this line at each point in time that they notice flatus passing through the anus. The acoustical volume of the event is indicated by the vertical distance that the pencil mark rises above the time line. Inaudible events are indicated by a short mark that extends only below the time line.
Environmental impact
Livestock are a significant contributing factor to the greenhouse effect, accounting for around 20% of global methane emissions. Less than 10% of the total greenhouse gas emissions from livestock is produced by animal flatulence; most is produced by animal burping. Livestock in New Zealand account for 60% of the country's greenhouse gas emissions. Livestock in Australia contribute approximately 14% of the country's greenhouse gas emissions.
Social context
In many cultures, excessive human flatulence is regarded as embarrassing and repulsive, even to the point of being a taboo subject. People will often strain to hold in the passing of gas when in polite company, or position themselves to conceal the noise and smell.
Flatulence is a potential source of humor, either due to the foul smell or the sounds produced. Some find humour in flatulence ignition, which is possible due to the presence of flammable gases such as hydrogen and methane, though the process can result in burn injuries to the rectum and anus.
posted by Pocahontas @ 9:55 PM
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