Belching

Eructation

ICD-10	R14
ICD-9	787.3

Belching (also known as burping, ructus, or eructation) involves the release of gas from the digestive tract (mainly esophagus and stomach) through the mouth. It is usually accompanied with a typical sound and, at times, an odor. In most parts of the world, especially in formal situations, audible burping is considered impolite but for the Inuit people of Canada it's an expression of thanks and appreciation for the meal.

Terminology

In the United States, "belching" is defined as being notably louder than "burping".

Physiology

Belching is typically caused by swallowing air when eating or drinking and subsequently expelling it, so in this case the expelled gas is mainly a mixture of nitrogen and oxygen. Burps can also be caused by drinking carbonated drinks such as beer, soft drinks, energy drinks or champagne, in which case the expelled gas is carbon dioxide from the drink itself. Common diabetes drugs metformin ^[1] and Byetta ^[2] can cause belching, especially at higher doses. This often resolves in a few weeks. Belching combined with other symptoms such as dyspepsia, nausea and heartburn may be a sign of an ulcer or hiatal hernia, and should be reviewed by a physician.^[3]

The sound of burping is caused by the vibration of the upper esophageal sphincter^[4] as the gas passes through it. The current Guinness world record for the loudest burp is 107.1 dB, set by Paul Hunn in 2008.^[5] (This is louder than a jackhammer at a distance of 1 meter.)

In microgravity environments, belching is normally associated with regurgitation. The valve at the top of the stomach (the gastroesophageal junction) does not produce a tight seal, and in the absence of gravity, the stomach contents tend to float near this loose seal, making them likely to come up along with the expelled air.^[6]

In infant

Babies are particularly subject to accumulation of gas in the stomach while feeding, and this can cause considerable agitation and/or discomfort unless the child is burped. The act of burping an infant involves placing the child in a position conducive to gas expulsion (for example holding the infant up to the adult's shoulder, with the infant's stomach resting on the adult's chest) and then lightly patting the lower back so that the child burps. Because burping can cause vomiting in infants, the "burp cloth" or "burp pad" is sometimes employed on the shoulder to protect the adult's clothing.

In other animals

Many other mammals, such as cattle, dogs, and sheep also burp. In the case of ruminants, the gas expelled is actually methane produced as a byproduct of the animal's digestive process. Anaerobic organisms such as Escherichia coli (E. coli) and methanogenic archaea produce this effect. An average cow is thought to emit between 542 litres (if located in a barn) and 600 litres (if in a field) of methane per day through burping and exhalation, making commercially farmed cattle a major contributor to the greenhouse effect. 95% of this gas is emitted through belching.^[7] This has led scientists at the Commonwealth Scientific and Industrial Research Organisation of Perth, Australia, to develop an anti-methanogen vaccine to minimize methane in cattle burps.^[8]

One reason that domesticated cows burp so much is because they are often fed foods that their digestive systems do not process, such as corn and soy. Some farmers have reduced burping in their cows by feeding them alfalfa and flaxseed, which are closer to the grasses that they had eaten in the wild before they were domesticated.^[9]

In some animals, a failure to burp successfully can be fatal. This is particularly common among domesticated ruminants that are allowed to gorge themselves on very rich spring clover or alfalfa. The condition, known as bloat, is basically a high pressure buildup of gastric gases and requires immediate veterinary treatment, usually the insertion of a flexible rubber hose down the esophagus—or in extreme cases the lancing of the animal's side with a trochar and cannula—to expel the buildup of gas. Some fish are also known to expel air from their gills; here the burp is produced by gas being expelled from the gas bladder.

References

1. ^ DailyMed: About DailyMed
2. ^ DailyMed: About DailyMed
3. ^ Eructation (Professional Guide to Signs & Symptoms (Fifth Edition)) - WrongDiagnosis.com
4. ^ GI Motility online: Upper esophageal sphincter - Ivan M. Lang, D.V.M., Ph.D.
5. ^ http://www.guinnessworldrecords.com/records/human_body/extreme_bodies/loudest_burp.aspx
6. ^ Vickie Kloeris (01 May 2001). Eating on the ISS. Interview with Lori Keith. National Aeronautics and Space Administration. Retrieved 2011-11-12.
7. ^ MyCattle Health News
8. ^ Burp vaccine cuts greenhouse gas emissions - New Scientist
9. ^ Greening the Herds: A New Diet to Cap Gas, New York Times, June 4, 2009

External links

• from Webmd.com