The human digestive system is a complex machine. Even before you swallow, the saliva in your mouth begins the digestive process that allows your body to absorb the nutrients in food. These include vitamins, minerals, proteins, carbohydrates and fats.

Three organs work together during the digestive process to help the body digest and absorb fats. They are the pancreas, liver and gall bladder.

The pancreas makes juices that help the body digest both fats and protein. The liver produces a substance called bile that helps to absorb the fats into the bloodstream. The gallbladder, which is attached to the liver via a duct, acts as a storing house for bile, releasing it when the body needs it.

The gallbladder is a small pouch located under the liver on the right side of the rib cage. It is about three inches long and less than one-and-a-half inches wide. It can store about 50 milliliters (or just under two ounces) of bile. When you eat a meal containing fats, your body sends a signal to the gallbladder to release its stored bile into the small intestine through a series of tubes called ducts. The bile helps to emulsify, or break down the fats contained in the pizza you had for lunch.

Bile is a bitter, yellow fluid that consists of three major components: cholesterol, bile salts and bilirubin. When these components get out of balance, gallstones can form.

No one knows exactly how the chemicals in bile become unbalanced, but there are certain factors that seem to make this more likely. These include: being over 40, being female, eating a diet that is high in fat or cholesterol content, being obese, rapid weight loss, estrogen intake, being pregnant and family history.

Gallstones may not cause any symptoms. When symptoms are present, they can vary from patient to patient. Classic symptoms consist of pain in the upper right abdomen just under the ribs. The pain often radiates from the abdomen to the back, begins a few hours after eating a fatty meal and can last from 30 minutes to several hours. Nausea and vomiting may also be present.

Certain symptoms require immediate medial attention and can indicate complications from gallstones including inflammation of the gallbladder (cholecystitis), gallbladder cancer, blockage of a bile duct or pancreatic duct. The symptoms include: abdominal pain so intense that you can’t find a comfortable position, yellowing of your skin or whites of your eyes and high fever with chills. Gallbladder complications are rare, however if you experience any of these symptoms, seek medical attention.

It is estimated that as many as 20 million Americans suffer from gallstones. For many the treatment includes removing the gallbladder. Since bile is produced by the liver, it is possible to remove the gallbladder and have the digestive system continue to function. This is typically done through laparoscopic procedure known as a cholecystectomy.

People who have had their gallbladders removed may find they do better eating smaller meals throughout the day, rather than large meals. They may also need to watch their fat intake and avoid foods that are high in fat content. Although there is no known way to prevent gallstones, eating a diet that is low in fat and cholesterol and high in fiber is always a good idea, and helps to promote overall digestive health.