Bile, a yellowish-green fluid produced by the liver in most vertebrates, is essential for the digestion of lipids. Human bile is mainly composed of water, about 97-98% water, and the remaining components include bile salts, bilirubin, fats, and inorganic salts. The role of bile in the digestive process, especially in the small intestine, is to aid in the emulsification and absorption of fat so that the lipids in food can be efficiently utilized.
The main functions of bile include emulsifying fat and promoting the absorption of fat-soluble vitamins, which allows our bodies to obtain better nutrient uptake.
In addition to water, bile secreted by the liver also contains approximately 0.7% bile salts, 0.2% bilirubin, 0.51% fat, and 200 mEq/L inorganic salts. Bile salts are an indispensable component of lipids. The two-sided nature of these bile salts allows them to form microcells around lipids. This structure not only increases the surface area of fats, but also provides more space for digestive enzymes to act. Thereby promoting the decomposition and absorption of lipids.
Insufficient bile caused by disease and improper diet can even lead to fat indigestion and affect overall health.
In the absence of bile, fatty stools may occur, a condition called fatty diarrhea, primarily because undigested fat is excreted in white or gray stools. Additionally, a buildup of cholesterol may lead to the formation of gallstones, which often require surgical removal of the gallbladder to treat.
Gallstones or obstruction of the bile ducts can lead to problems such as jaundice, which shows the importance of bile in maintaining good health.
Historically, medical theory believed that the body's health was related to the balance of four "fluids", two of which were related to bile. In addition, baby albumin and some printed soaps also contain bile, and they have a long history of use in stain removal.
Some cultures use bile as an ingredient. For example, in the Filipino cuisine "Pinapaitan", bile is used as a seasoning. Bear bile is also used as a medicinal ingredient in traditional medicine, but the practice has faced controversy, with many animal rights groups condemning it.
In summary, bile carries multiple physiological functions, from digesting fats to serving as a pathway for excretion of toxins, and both its composition and function are necessary to maintain our health. Have you ever thought about how your daily eating habits affect the production and secretion of bile?