Gallstones are hard particles that develop in the gallbladder. The gallbladder is a small, pear-shaped organ located in the upper right abdomen, the area between the chest and hips, below the liver.
Gallstones can range in size from a grain of sand to a golf ball. The gallbladder can develop a single large gallstone, hundreds of tiny stones, or both small and large stones. Gallstones can cause sudden pain in the upper right abdomen. This pain, called a gallbladder attack or biliary colic, occurs when gallstones block the ducts of the biliary tract
What is a biliary tract?
The biliary tract consists of the gallbladder and the bile ducts. The bile ducts carry bile and other digestive enzymes from the liver and pancreas to the duodenum, the first part of the small intestine.
The bile ducts of the biliary tract include the hepatic ducts, the common bile duct, the pancreatic duct and the cystic duct. The gallbladder stores bile. Eating signals the gallbladder to contract and empty bile through the cystic duct and common bile duct into the duodenum to mix with food.
What causes Gallstones?
Imbalances in the substances that make up bile cause gallstones. Gallstones may form if bile contains too much cholesterol, too much bilirubin or not enough bile salts. Scientists do not fully understand why these imbalances occur. Gallstones also may form if the gallbladder does not empty completely or often enough.
The two types of gallstones are cholesterol and pigment stones:
- Cholesterol stones, usually yellow-green in color, consist primarily of hardened cholesterol. In the United States, more than 80 percent of gallstones are cholesterol stones.
- Pigment stones, dark in color, are made of bilirubin.
Who is at risk for gallstones?
Certain people have a higher risk of developing gallstones than others.
- Women are more likely to develop gallstones than men. Extra estrogen can increase cholesterol levels in bile and decrease gallbladder contractions, which may cause gallstones to form. Women may have extra estrogen due to pregnancy, hormone replacement therapy or birth control pills.
- People over the age of 40 are more likely to develop gallstones than younger people.
- People with a family history have a higher risk.
- American Indians have genetic factors that increase the amount of cholesterol in their bile. In fact, American Indians have the highest rate of gallstones in the United States — almost 65% of women and 30% of men have gallstones.
- Mexican Americans are at higher risk of developing gallstones.
Other factors that affect a person’s risk of gallstones include:
- Obesity. People who are obese, especially women, have increased risk of developing gallstones. Obesity increases the amount of cholesterol in bile, which can cause stone formation.
- Rapid weight loss. As the body breaks down fat during prolonged fasting and rapid weight loss, the liver secretes extra cholesterol into bile. Rapid weight loss can also prevent the gallbladder from emptying properly. Low calorie diets and bariatric surgery, (surgery that limits the amount of food a person can eat or digest) can lead to rapid weight loss and increased risk of gallstones.
- Diet. Research suggests diets high in calories and refined carbohydrates and low in fiber increase the risk of gallstones. Refined carbohydrates are grains processed to remove bran and germ, which contains nutrients and fiber. Examples of refined carbohydrates include white bread and white rice.
- Certain intestinal diseases. Diseases that affect normal absorption of nutrients, such as Crohn’s Disease, are associated with gallstones.
- Metabolic syndrome, diabetes and insulin resistance. These conditions increase the risk of gallstones. Metabolic syndrome also increases the risk of gallstone complications. Metabolic syndrome is a group pf traits and medical conditions linked to being overweight or obese that puts people at risk for heart disease and type 2 diabetes.