Bilirubin is a metabolic waste product generated internally by the body, not an ingredient found in food. This yellow pigment results from the natural breakdown of old red blood cells and must be processed by the liver for excretion. Disruptions in this internal process can lead to elevated levels. While diet does not supply bilirubin, it plays a supporting role in the body’s ability to process and eliminate it efficiently.
What Bilirubin Is and Where It Comes From
Bilirubin is a brownish-yellow pigment that forms when red blood cells, which live about 120 days, are broken down. The hemoglobin is split, and the heme portion is converted first into biliverdin, then into unconjugated, or indirect, bilirubin. This unconjugated form is not water-soluble, so it binds to albumin in the bloodstream for transport to the liver.
In the liver cells, bilirubin undergoes conjugation, where it is bound to glucuronic acid by an enzyme. This conversion creates conjugated, or direct, bilirubin, which is now water-soluble and mixes with bile. The liver secretes this conjugated bilirubin into the bile ducts and releases it into the small intestine.
In the intestines, bacteria convert the conjugated bilirubin into urobilinogen. Much of the urobilinogen is further broken down into stercobilin, which gives stool its characteristic brown color. A small amount of urobilinogen is reabsorbed and excreted by the kidneys, giving urine its yellow tint.
Common Causes of Elevated Bilirubin Levels
Elevated bilirubin levels, known as hyperbilirubinemia, occur when the body’s processing or elimination pathway is compromised, often resulting in jaundice. Causes are categorized based on where the disruption occurs in the metabolic pathway. Pre-hepatic causes involve excessive red blood cell breakdown, such as in hemolytic anemia, which overwhelms the liver’s capacity to process unconjugated bilirubin.
Hepatic causes involve damage or dysfunction within the liver itself, preventing the organ from effectively conjugating bilirubin. Conditions like hepatitis, cirrhosis, or genetic disorders such as Gilbert’s syndrome can impair this ability. This results in a buildup of either unconjugated or conjugated bilirubin, depending on the specific impairment.
Post-hepatic causes involve an obstruction of the bile ducts after the liver has processed the bilirubin. Blockages, often caused by gallstones or tumors, prevent conjugated bilirubin from being excreted into the small intestine. When bile flow is blocked, the conjugated bilirubin backs up into the bloodstream, sometimes leading to its excretion in the urine.
How Diet Supports Bilirubin Processing
While food does not contain bilirubin, a supportive diet enhances the body’s ability to process and eliminate this waste product by supporting liver function and bile flow. A diet rich in fiber binds to conjugated bilirubin in the intestines, aiding its removal through stool and reducing reabsorption. Soluble fiber, found in foods like oats, apples, and legumes, promotes efficient excretion.
Antioxidant-rich foods support the liver’s detoxification processes alongside bilirubin conjugation. Brightly colored fruits and vegetables, such as berries and broccoli, contain compounds that help protect liver cells from damage. Lean proteins, including fish and poultry, provide the amino acids necessary for maintaining and repairing liver tissue.
Hydration is an effective dietary factor that helps the liver and kidneys flush out waste products, easing the systemic burden. Conversely, certain items should be limited or avoided because they increase the workload or damage the liver, impairing bilirubin processing. These include excessive alcohol consumption, high intakes of processed fats, and refined sugars, which contribute to liver stress.