Bile or gall is a greenish yellow substance which is synthesized in the liver and passed to the gallbladder for concentration and storage or transported to first region of the small intestine(duodenum). It aids in the digestion of fats in the duodenum.
Bile process is a vital function of the liver. Knowledge of how bile formation mechanism has progressed hugely in recent years and has provided the basis for further diagnosis and treatment of cholestatic disorders.
When bile acids are conjugated with glycine and taurine amino acids, they form bile salts. Bile salts are the major organic solutes in bile and normally function to emulsify dietary fats and facilitate their intestinal absorption. we produce 400 to 800 ml of bile daily.
Bile is composed of bile acids and salts, phospholipids, cholesterol, pigments, water, and electrolyte chemicals that keep the total solution slightly alkaline (with a pH of about 7 to 8).
Bile acids are derivatives of cholesterol(synthesized in the hepatocyte).
Bile also contains bile pigments which are excretory products of the liver and include biliverdin and bilirubin. Bilirubin is a breakdown product of haemoglobin and is conjugated in the liver and secreted into bile. Bile pigments are normally excreted in the faeces and make the faeces appear brown. Problems in the liver or biliary tree often result in the accumulation of bilirubin in the blood, which manifests as jaundice(Jaundice is a disease that causes the yellowish pigmentation of the skin and eyes due to excessive bilirubin levels in the blood).
Gallstones are small lumps of solid material that form in the gall bladder. Abnormal concentrations of bile acids can increase the risk of precipitation of bile out of solution to form stones. They can be made up entirely of cholesterol or bile pigments. Risk factors for gallstone formation include being female, obesity, age >40, and poor diet.
foods affecting bile
foods that help regulate gall or bile levels are bell peppers, citrus fruits, dark and leafy greens, tomatoes, milk, fish(especially sardine) and shellfish, low-fat dairy, beans, nuts, lentils, tofu and tempeh.
Eating a healthy, well-balanced diet full of fruits and vegetables is the best way to improve and protect your gallbladder’s health. Fruits and vegetables are full of nutrients and fiber, the latter of which is essential to a healthy gallbladder. It’s thought that eating more plant-based protein could also help prevent gallbladder disease.
meanwhile, you should try to avoid foods like vegetable oil, peanut oil, refined white foods and foods high in fat processed foods since they mess up your bile secretion.
The biggest problem foods are high-fat and processed foods. Foods that are greasy or fried in oils like vegetable oil and peanut oil are more difficult to break down and can cause gallbladder problems. Foods with trans fats, like those in processed or commercially baked products, can also be harmful to gallbladder health. You should also avoid alcohol and tobacco.
Only approximately 5% of these bile acids are eventually excreted and Bile consists of ~95% water in which are dissolved a number of endogenous solid constituents including bile salts, bilirubin phospholipid, cholesterol, amino acids, steroids, enzymes, porphyrins, vitamins, and heavy metals, as well as exogenous drugs, xenobiotics and environmental toxins.
The gall bladder stores and concentrates bile during the fasting state. Typically, bile is concentrated five-fold in the gall bladder by absorption of water and small electrolytes – virtually all of the organic molecules are retained.
Bile salts are composed of the salts of four different kinds of free bile acids (cholic, deoxycholic, chenodeoxycholic, and lithocholic acids); each of these acids may in turn combine with glycine or taurine to form more complex acids and salts. Bile salts and acids can be synthesized from cholesterol or extracted from the bloodstream by the liver. They pass from the liver into the small intestine, where they act as detergents to emulsify fat and reduce the surface tension on fat droplets to prepare them for the action of pancreatic and intestinal fat-splitting enzymes. The salts are large, negatively charged ions that are not readily absorbed by the upper region of the small intestine; consequently, they remain in the small intestine until most of the fat is digested. In the lower small intestine, the salts and acids are absorbed and passed back into the bloodstream until they are once again extracted by the liver; this cycle, from the liver to the small intestine and blood and then back to the liver, is called enterohepatic circulation. Some salts and acids are lost during this process; these are replaced in the liver by continual synthesis from cholesterol. The rate of synthesis is directly related to the amount of acids and salts lost. Bile salts do not normally reach the colon; when they do, however, they may inhibit the absorption of water and sodium, causing a watery diarrhea.
Role of Bile Acids in Cholesterol Homeostasis
synthesis of bile acids in liver accounts for the majority of cholesterol breakdown in the body. 500 mg of cholesterol are converted to bile acids and eliminated in bile every day. This route for elimination of excess cholesterol is probably important in all animals, but particularly in situations of massive cholesterol ingestion.
Interestingly, it has recently been demonstrated that bile acids participate in cholesterol metabolism by functioning as hormones that alter the transcription of the rate-limiting enzyme in cholesterol biosynthesis.
Bile salts and acids are transported in a fluid that contains water, sodium, chloride, and bicarbonates. This fluid is produced in the liver, and it serves to neutralize hydrochloric acid passed from the stomach into the small intestine. Water-insoluble wastes that the liver removes from blood, such as cholesterol, steroids, drugs, and hemoglobin pigments, are carried in the fluid to the excretory system. Hemoglobin pigments are broken down, producing several bile fluid compounds, including bilirubin, which has no known function other than that of a colouring agent. Traces of other substances can also be found in bile including mucus, serum proteins, lecithin, neutral fats, fatty acids, and urea.
Pattern and Control of Bile Secretion
as mentioned, The flow of bile is lowest during fasting, and a majority of that is diverted into the gallbladder for concentration. When chyme from an ingested meal enters the small intestine, acid and partially digested fats and proteins stimulate secretion of cholecystokinin and secretin. As discussed previously, these enteric hormones have important effects on pancreatic exocrine secretion. They are both also important for secretion and flow of bile:
The most potent stimulus for release of cholecystokinin is the presence of fat in the duodenum. Once released, it stimulates contractions of the gallbladder and common bile duct, resulting in delivery of bile into the gut.
Secretin: This hormone is secreted in response to acid in the duodenum. Its effect on the biliary system is very similar to what was seen in the pancreas – it stimulates biliary duct cells to secrete bicarbonate and water, which expands the volume of bile and increases its flow out into the intestine.
bile reflux
Bile reflux occurs when bile backs up (refluxes) into your stomach and, in some cases, into the tube that connects your mouth and stomach (esophagus).
Bile reflux may accompany the reflux of stomach acid (gastric acid) into your esophagus. Gastric reflux may lead to gastroesophageal reflux disease (GERD), a potentially serious problem that causes irritation and inflammation of esophageal tissue.
Bile and food mix in the duodenum and enter your small intestine. The pyloric valve, a heavy ring of muscle located at the outlet of your stomach, usually opens only slightly — enough to release about an eighth of an ounce (about 3.75 milliliters) or less of liquefied food at a time, but not enough to allow digestive juices to reflux into the stomach.
Unlike gastric acid reflux, bile reflux can’t be completely controlled by changes in diet or lifestyle. Treatment involves medications or, in severe cases, surgery.
There are two primary types of gallbladder problems: cholecystitis (inflammation of the gallbladder) and cholestasis (gallstones). Some people with gallstones don’t experience any symptoms. In those that do, symptoms of gallbladder problems can include:
pain on the upper right side of the abdomen, especially following meals and eating fatty foods
loss of appetite
nausea
vomiting
jaundice, if the gallbladder ducts are blocked
low-grade fever
tea-colored urine
light-colored stools
Causes
excess weight
rapid weight loss followed by weight gain
coronary artery disease
diabetes
diets high in refined carbohydrates and calories but low in fiber
ignoring existing food allergies, like celiac disease
lactose intolerance
What leads to bile reflux?
Bile reflux may be caused by:
Surgery complications: Stomach surgery, including total or partial removal of the stomach and gastric bypass surgery for weight loss, is responsible for most bile reflux.
Peptic ulcers: A peptic ulcer can block the pyloric valve so that it doesn’t open or close properly. Stagnant food in the stomach can lead to increased gastric pressure and allow bile and stomach acid to back up into the esophagus.
Gallbladder surgery: People who have had their gallbladders removed have significantly more bile reflux than do people who haven’t had this surgery.