What Causes Gallstones?

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What are Gallstones?

Gallstones are solid particles called stones that develop in the gallbladder, a small pear-shaped organ located behind the liver just above the right portion of the rib cage. The gallbladder allows the digestive liquids called bile to excrete after you eat high cholesterol foods to digest fat. Bile consists of cholesterol, bilirubin, acids, and other waste materials. If bile contains too much cholesterol or bilirubin and bile cannot dissolve them, the cholesterol and bilirubin might turn into gallstones.

Cholesterol Gallstones

Cholesterol gallstones consist of undissolved cholesterol and are commonly yellow in color. The liver regulates cholesterol, a fatlike substance, and releases it into bile to help get rid of excessive fat from the body. The bile cannot dissolve fatty cholesterol due to its indissolubility, as bile is a watery solution. Therefore, the liver ejects substances like bile acids to help dissolve cholesterol. After fat is dissolved, enzymes digest it. However, the bile acids cannot do that at times since too much cholesterol is indissoluble. Indissoluble cholesterol ultimately develops in size and crystallizes into gallstones.

In addition, you might have gallstones because your gallbladder does not drain properly, making it possible for bile to exist in the gallbladder. This gives cholesterol materials a chance to accumulate in the gallbladder and to form gallstones.

Pigment Gallstones

Hemoglobin, the protein molecule in red blood cells, may develop into a byproduct known as pigment. Bilirubin can derive from old red blood cells and it is finally excreted into the blood. The liver separates bilirubin from the blood and finally excretes it. Two possible types of pigment gallstones are brown pigment gallstones and black pigment gallstones.

Brown pigment gallstones might develop as a reduced contraction of the gallbladder enables bacteria to rise from the duodenum into the gallbladder and bile ducts. The chemical process involves bacteria that turn bilirubin into the modified one and blend it with calcium to create pigment. Gallstones may arise from pigment that mingles with cholesterol in bile. Gallstones can appear brownish in color.

Black pigment gallstones can occur because the abundance of bilirubin in bile enables it to mingle with substances in bile, such as calcium, and develop into pigment. This pigment is hard to dissolve in bile and gradually develops into gallstones with black in color.

Other Risk Factors

Some other risk factors that enable gallstones to be present in the gallbladder include:

  • Being over 60 years old (the older you are, the more likely you are to have gallstones)
  • Female gender (especially during pregnancy)
  • Being either overweight or obese
  • Family history of gallstones
  • Ethnic factor (American Indians and Mexican Americans are more susceptible to develop gallstones)
  • High intake in foods containing high trans-fat and cholesterol
  • Rapid weight loss due to diet or weight-loss surgery
  • Medications for lowering cholesterol
  • Having diabetes due to triglycerides (high fatty acids)
  • Having cirrhosis (severely scarred liver)


MayoClinic.com: Gallstones: Causes - https://www.mayoclinic.com/health/gallstones/DS00165/DSECTION=causes

Medicinenet.com: What are Gallstones? - https://www.medicinenet.com/gallstones/article.htm

The National Digestive Diseases Information Clearinghouse: Gallstones - https://digestive.niddk.nih.gov/ddiseases/pubs/gallstones/