What is bile?

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The importance of Bile in digestion

Healthylife Pharmacy21 January 2020|5 min read

Bile is a fluid produced in the liver and stored in the gallbladder containing primarily cholesterol, bile acids and bilirubin (a product from the breakdown of red blood cells).You may think that bile is just a bitter acid you taste letting you know when you have eaten too many fats. It actually plays an important role in digestion. The digestion of fats and fat-soluble vitamins – A, D, E and K for absorption in the small intestine and helping in the elimination of bilirubin and wastes are all the responsibility of bile.

What is Bile?

Bile is a secretion from hepatocytes (liver cells) consisting of water, cholesterol, lecithin (phosphatidylcholine), bile salts, bile pigments and several ions. The colour of bile is described as anywhere from olive green, yellow to brown. The principal pigment is bilirubin, derived from heme (an iron-containing compound) which is released from the breakdown of aged red blood cells, secreted into the bile and eventually broken down by the intestines.

Bile acids and their salts are the most important solutes determining the extent of bile flow and the management of cholesterol levels. 

Secondary bile salts are created by the action of intestinal bacteria on primary bile salts in the intestine. Bile salts play crucial roles in allowing the gastrointestinal system to digest, transport and metabolize nutrients. The secreted bile enters small canals into bile ducts within the liver and exit through the common hepatic ducts.The gall bladder stores and concentrates bile from the liver until it is needed by the small intestine. The gall bladder is lined with columnar epithelium which absorbs ions and water during the concentration process.

The Role of bile

Digestion of fats and fat-soluble vitamins. The primary role of bile is to emulsify (blend) lipids (fats) prior to digestion.

The hepatocytes secrete around 800 – 1000mLs of bile. Bile salts (potassium and sodium salts) are important for the emulsification of dietary fats. Emulsification is the breakdown of large globules of lipids into a suspension of small lipid globules. This allows pancreatic enzymes (lipases) to more quickly complete the digestion of triglycerides. Bile salt continue to help with the absorption of lipids thoughout the digestive process.

The hepatocytes are continuously releasing bile and production is increased throughout digestion and absorption. After which (between meals) bile is stored in the gall bladder and the passage through to the small intestine is closed.

As you might presume, due to bile being composed primarily of cholesterol, keeping its flow into the small intestine and, by elimination through faeces, aids in reducing excess cholesterol from the body.

Improving bile flow can result in lowered cholesterol levels.

Toxin removal. Bile plays an important role in the removal of toxins from the body. Toxins from liver detoxification processes are secreted into bile and eliminated through faeces (bowel function).

Hormonal function. Bile salts function as "nutrient signalling hormones" activating specific receptors. Bile salts also are presumed to collaborate with insulin in the regulation of the metabolism of nutrients into the liver.

Common disorders of the biliary system

The importance of bile secretion to health is usually evident when its secretion is impaired. This can occur do to developmental, genetic or acquired cholestatic diseases.

Cholecystitis (gallstones in the gallbladder)

There are three main types:

  • Cholesterol stones
  • Brown pigment stones – linked to helminthic (parasitic worms) or bacteria in the biliary tract
  • Calcium bilirubinate – due to haemolytic disorders (blood cell destruction)

Cholesterol stones

These can occur due to too much secretion of cholesterol (hypersecretion) and too little secretion of bile salts and lecithin (hyposecretion) which reduces the ability of the bile salts and lecithin to solubilise cholesterol. This then causes a precipitation of chemical compounds of bile into vesicles (gallstones) throughout the gallbladder and sometimes the bile duct. Precipitation is the formation of stones. Chronic cholecystitis (inflammation of the gallbladder) is the most common presentation of pain in the right upper abdominal area.  

Impaired gallbladder emptying has been linked with the pathogenesis of cholesterol gallstones

Risk factors for gallstones include:

  • Aging – causing a decrease in biliary salts cholesterol breakdown enzymes.
  • Obesity – increased secretion of bile from the liver with cholesterol supersaturation.
  • Dieting – rapid weight loss, weight cycling and prolonged fat-restriction may exacerbate gallbladder stasis (a lack of movement of bile).
  • Diet – a diet high in carbohydrates and high triglycerides in the blood are associated with gallstones.
  • Dyspepsia (indigestion) – associated with helicobacter pylori bacteria and slow digestive transit time.
  • Females – in pregnancy, due to endogenous oestrogens.

Chronic gastritis

Bile acids may be a causative factor in chronic gastritis. Food mixes with bile acids in the duodenum and enter the small intestine through a valve called the pyloric valve. 

Reflux can occur when digestive liquid “backs-up’ into the stomach and in some cases, the oesophagus (the tube from your stomach to the mouth). This can lead to gastrointestinal reflux disease (GERD), causing irritation and inflammation. 

Although bile itself is not considered in most cases to be responsible for GERD, gastric acid is the usual culprit.

In cases of bile reflux, the pyloric valve doesn't close properly, allowing bile to wash back into the stomach. This can lead to inflammation of the stomach lining. 

This can occur due to:

  • Peptic ulcers – which may block the pyloric valve resulting in poor opening, slowing the digestive process and causing food stagnation and increased gastric pressure – pushing upwards.
  • Gallbladder surgery – this often results in more bile being produced.
  • Stomach surgery – such as stomach removal (gastrectomy) and gastric bypass surgery for weight loss. 

Treatment for bile acid reflux is different from gastric acid reflux. In all cases a medical diagnosis should be sort.

Jaundice

Jaundice can occur when there is a build-up of a yellow compound bilirubin. Symptoms include a yellow colouring of the skin, whites of the eyes, the mucous membranes and urine. Skin may itch. It usually indicates there is a problem with the liver or bile duct. This could be due to many reasons, such as an inflamed liver or obstructed bile duct for instance. Bilirubin is formed from the heme pigment from the breakdown of aged red blood cells. This pigment is transported to the liver and eventually excreted in bile. Jaundice is a common condition in newborns and usually due to an immature liver unable to remove bilirubin in the bloodstream system. Jaundice is a medical conditions and treatment is based on the cause.

Insufficient bile acid

Not enough bile acid can result in malabsorption of dietary fats and fat-soluble vitamins and mainly occurs in people who have had their gallbladders removed.

Symptoms include:

  • Digestive gas – causing stomach cramps and foul smells
  • Diarrhoea or erratic bowel movements which may be pale in colour
  • Weight loss

Fats and fat-soluble vitamins play many important roles in the body. The fat-soluble vitamins - A, D, E and K are needed for such things as vision, immune health, bone formation, blood clotting and as an antioxidant against free-radical damage to cells. Dietary fats are needed for the absortion of many important nutrients and the production of important hormones. They are essential to for energy, to support cell growth, to help cushion and protect organs and help keep warmth in the body.

How to support healthy bile production

Naturopathic consideration in the prevention of gallstones and to encourage good bile flow include:

Stimulate bile release using food

The gall bladder stores and concentrates bile salts during fasting and releases them into the duodenum in response to gastric emptying of a meal. The hormone, cholecystokinin (CCK), is responsible for regulation of this process in response to macronutrients, especially fat, in digestion. Dietary protein stimulates CCK secretion.

Turmeric, coffee, tea, fat, semi-skimmed milk and dairy products in studies have been found to increase gallbladder emptying.

Long-chain fatty acids were found to be the best fats to help gallbladder constriction. These includes fatty fish such as salmon and mackerel; shellfish such as shrimps, prawns, crabs, and also algae from clean sources. Flaxseeds and flax oil and chia seeds. 

Avoid sudden weight reduction or severe reduction in dietary fats

Good bile formation in the liver can be encouraged by herbs known as choleretics

  • Turmeric (Curcuma longa)
  • Globe artichoke (Cynara scolymus)
  • Barberry (Berberis vulgaris)
  • Oregon grape (Berberis aquifolium)

For bile motility and function (cholagogues)

  • Globe artichoke (Cynara scolymus)
  • Dandelion (Taraxacum officinale)
  • Flax seed oil 
  • Evening primrose oil

Choleretics and cholagogues herbs can help with:

Bilious conditions – nausea, feeling full after meals, headaches associated with alcohol and fatty foods

Sluggish bowel - constipation

Skin conditions associated with toxins such as– acne and eczema and autoimmune disorders

Non-impacted gallstones – but not obstructed bile ducts

Moderate cholecystitis

Jaundice – but not unconjugated hyperbilirubinemia

Reduce cholesterol and bile reabsorption in the small intestine

The liver is able to sense the loss of bile salt in the faeces and will increased synthesis of cholesterol to equal loss. By increasing cholesterol elimination through the bowel, will also help in the reduction of stored cholesterol, thus reducing levels in the body.

Increase elimination by:

  • Fibres such as psyllium husks and beta glucan
  • Probiotics for optimum bowel digestive function
  • Niacin
  • Globe artichoke (Cynara scolymus)
  • Dandelion (Taraxacum officinale)

Healthy liver function

Adopt a healthy diet and lifestyle. Bile formation and secretion is a unique and vital function of the liver. Taking care of your liver by be avoiding toxins - such as alcohol, processed foods, and foods containing artificial flavours, preservatives and colours. Instead eat mainly wholesome whole foods - vegetables, fruits, nuts, seeds and grains.  

References

  1. Bile Formation and Secretion https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4091928/
  2. Cholesterol crystallisation in bile https://gut.bmj.com/content/41/2/138
  3. Bile Acids are Nutrient Signaling Hormones https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4073476/
  4. Complementary and alternative treatment in functional dyspepsia https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5802680/
  5. Berberis vulgaris: specifications and traditional uses https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5478785/
  6. Blocking intestinal cholesterol absorption for optimal lipid lowering https://www.ajmc.com/journals/supplement/2004/2004-06-vol10-n1treatmentsofdyslipidemiatabloid/jun04-1805p2
  7. https://www.mayoclinic.org/diseases-conditions/bile-reflux/symptoms-causes/syc-20370115
  8. Effects of various food ingredients on gall bladder emptying https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3898429/
  9. Long-chain polyunsaturated fatty acid sources and evaluation of their nutritional and functional properties https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4237475/
  10. Mills, Simon and Bone, Kerry; 2000, Principles and practice of Phytotherapy, Churchill Livingstone, Aust
  11. Sarris, Jerome and Wardle, Jon; 2014, Clinical Naturopathy 2e, Elsevier, NSW Australia