Bile (yellow material) in a liver biopsy in the setting of bile stasis, i.e. cholestasis. H&E stain

Action of bile salts in digestion

Bile or gall is a bitter-tasting, dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the process of digestion of lipids in the small intestine. In many species, bile is stored in the gallbladder and upon eating is discharged into the duodenum. Bile is a composition of the following materials: water (85%), bile salts (10%), mucus and pigments (3%), fats (1%), inorganic salts (0.7%) and cholesterol (0.3%).

In the medical theories prevalent in the West from Classical Antiquity up to the Middle Ages, the body's health depended on the equilibrium between four "humors" or vital fluids: blood, phlegm, "yellow bile" (or choler) and "black bile". Excesses of the last two humors were thought to produce aggression and depression, respectively; and the Greek names for them gave rise to the English words "cholera" and "melancholia". Those same theories explain the derivation of the English word "bilious" from "bile", and the meaning of "gall" in English as "exasperation" or "impudence".

Physiological functions[link]

Bile acts to some extent as a surfactant, helping to emulsify the fats in the food. Bile salt anions have a hydrophilic side and a hydrophobic side, and therefore tend to aggregate around droplets of fat (triglycerides and phospholipids) to form micelles, with the hydrophobic sides towards the fat and hydrophilic towards the outside. The hydrophilic sides are positively charged due to the lecithin and other phospholipids that compose bile, and this charge prevents fat droplets coated with bile from re-aggregating into larger fat particles. Ordinarily, the micelles in the duodenum have a diameter of around 14-33 μm.

The dispersion of food fat into micelles thus provide a largely increased surface area for the action of the enzyme pancreatic lipase, which actually digests the triglycerides, and is able to reach the fatty core through gaps between the bile salts. A triglyceride is broken down into two fatty acids and a monoglyceride, which are absorbed by the villi on the intestine walls. After being transferred across the intestinal membrane, fatty acids are reformed into triglycerides, then absorbed into the lymphatic system through lacteals. Without bile salts, most of the lipids in the food would be passed out in feces, undigested.

Since bile increases the absorption of fats, it is an important part of the absorption of the fat-soluble substances, such as the vitamins D, E, K and A.

Besides its digestive function, bile serves also as the route of excretion for bilirubin, a byproduct of red blood cells recycled by the liver. Bilirubin derives from haemoglobin by glucuronidation.

The alkaline bile also has the function of neutralizing any excess stomach acid before it enters the ileum, the final section of the small intestine. Bile salts also act as bactericides, destroying many of the microbes that may be present in the food.

Bile soap[link]

Bile from slaughtered animals can be mixed with soap. This mixture, called bile soap,^[1] can be applied to textiles a few hours before washing and is a traditional and rather effective method for removing various kinds of tough stains.

Abnormal conditions associated with bile[link]

• The cholesterol contained in bile will occasionally accrete into lumps in the gallbladder, forming gallstones. Cholesterol gallstones are generally treated through surgical removal of the gallbladder. However, they can sometimes be dissolved by increasing the concentration of certain naturally occurring bile acids, such as chenodeoxycholic acid and ursodeoxycholic acid.

• On an empty stomach – after repeated vomiting, for example – a person's vomit may be green or dark yellow, and very bitter. The bitter and greenish component may be bile or normal digestive juices originating in the stomach^{[citation needed]} The color of bile is often likened to "fresh-cut grass"^{[citation needed]}, unlike components in the stomach that look greenish yellow or dark yellow. Bile may be forced into the stomach secondary to a weakened valve, the presence of certain drugs including alcohol, or powerful muscular contractions and duodenal spasms.
• In the absence of bile, fats become indigestible and are instead excreted in feces, a condition called steatorrhea. Feces lack their characteristic brown color and instead are white or gray, and greasy.^[2] Steatorrhea can lead to deficiencies in essential fatty acids and fat-soluble vitamins. In addition, past the small intestine (which is normally responsible for absorbing fat from food) the gastrointestinal tract and gut flora are not adapted to processing fats, leading to problems in the large intestine.

Principal bile acids[link]

See also[link]

• Bile acid sequestrant
• Bile bear
• Intestinal juice
• Ox gall

References[link]

Notes

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2011)

Bibliography

• Bowen, R. (2001-11-23). "Secretion of Bile and the Role of Bile Acids In Digestion". Colorado State Hypertextbook article on Bile. http://www.vivo.colostate.edu/hbooks/pathphys/digestion/liver/bile.html. Retrieved 2007-07-17. 
• Krejčí, Z; Hanuš L., Podstatová H. & Reifová E (1983). "A contribution to the problems of the pathogenesis and microbial etiology of cholelithiasis". Acta Universitatis Palackianae Olomucensis Facultatis Medicae 104: 279–286. PMID 6222611. 
• Maton, Anthea; Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN 0-13-981176-1. 

External links[link]

• Photo of bear bile sample in an animal welfare blog by Paul Kraaijer.

Abdi Bile

Personal information
Full name	عبدالله بله عبدالله
Nationality	Somalia
Born	(1962-12-28) December 28, 1962 (age 49) Las Anod, Sool
Height	1.85 metres (6 ft 1 in)
Weight	75 kilograms (170 lb)
Sport
Sport	Running
Event(s)	800 metres 1500 metres

Abdi Bile (Somali: عبدالله بله عبدالله, Cabdi Bille Cabdi, born December 28, 1962) is a former middle distance runner. He was born in Las Anod, Somalia. In 1987 he became world champion in the 1500 metres, the first Somali to do so.

Career[link]

Bile won the 1500 m World Championship in 1987, running the final 800 m of the race in 1:46.0, the fastest final 800 m of any 1,500 meter race in history. He was a two-time Olympian (1984 and 1996) and dominated the event in the late 1980s. Bile was ranked first in the world at the mile distance in 1989. He was World Cup champion in the 1500 m in 1989 and two-time world Grand Prix final champion.

Bile graduated from George Mason University with a BS in marketing management. At George Mason, Bile was team captain and a two-time NCAA Division I 1,500 meter champion, winning his first title in 1985 (3:41.2) and the second in 1987 (3:35.79). He also won many conference titles and held the inter-collegiate 1500 m record for more than ten years. He was coached by John Cook, the former coach of 2008 Olympic 10,000 meter bronze medalist Shalane Flanagan. His career was riddled with injuries, and he missed the 1991 World Championships as well as the 1988 and 1992 Olympics because of such problems. In 1996 he finished 6th in the Olympic 1500 m final.

Bile has traveled widely and has inspired many young people and helped several humanitarian organizations. He is married, with a son named Ahmed, born in 1993. As a senior in high school, Ahmed won the Virginia state cross country title, the 1000m title and 1600m title along with being a two-time New Balance All-American in the 800m.

Personal bests[link]

• 800 metres - 1:43.60 (1989)
• 1000 metres - 2:14.50 (1989)
• 1500 metres - 3:30.55 (1989)
• One mile - 3:49.40 (1988)
• 3000 metres - 7:42.18 (1994)

Achievements[link]

References[link]

• IAAF profile for Abdi Bile