From the Guidelines
Fasting can indeed increase bilirubin levels in the blood, particularly in individuals with underlying liver conditions, as evidenced by a significant increase in serum bilirubin in cirrhotic patients who fasted during Ramadan 1. When considering the impact of fasting on bilirubin levels, it's essential to differentiate between healthy individuals and those with pre-existing liver conditions. In healthy individuals, the increase in bilirubin during fasting is typically mild and temporary. However, in patients with cirrhosis, fasting can lead to a more significant elevation in bilirubin levels, with older age, Child class C, and diabetes being independent factors for bilirubin elevation 1. Some key points to consider:
- Fasting can increase the breakdown of red blood cells, leading to higher bilirubin production as a byproduct.
- Temporary reduction in liver function efficiency during fasting can slow the processing and excretion of bilirubin.
- The elevation in bilirubin during fasting is usually temporary and returns to normal once regular eating resumes.
- Significant yellowing of the skin or eyes (jaundice) during fasting warrants immediate medical attention as it may indicate a more serious condition. In the context of cirrhotic patients, the available evidence suggests that Child class A patients may benefit from fasting Ramadan, while Child class C patients should be advised against fasting, especially if diabetic or with a history of GI bleeding 1. For Child class B patients, the evidence is less clear, but a recommendation against fasting has been suggested based on clinical experience and practice 1.
From the Research
Effect of Fasting on Bilirubin Levels
- Fasting has been associated with increased bilirubin levels in several studies 2, 3, 4, 5, 6
- A study published in Gastroenterology in 1997 found that fasting for 48 hours resulted in enhanced enterohepatic circulation of bilirubin, which is a major factor in the pathogenesis of fasting-induced hyperbilirubinemia 2
- Another study published in The Journal of surgical research in 1991 found that short-term fasting increased biliary calcium and bilirubin levels in prairie dogs 3
- A modeling study published in The American journal of physiology in 1981 found that fasting increased bilirubin turnover in patients with Gilbert's syndrome 4
- A study published in Gastroenterology in 1977 found that fasting stimulated bilirubin formation in the liver of newborn rats 5
- A retrospective study published in Journal of clinical pathology in 2014 found that fasting increased serum bilirubin levels in clinically normal, healthy males but not females 6
Key Findings
- Fasting can increase bilirubin levels in both males and females, although the effect may be more pronounced in males 6
- The mechanism of fasting-induced hyperbilirubinemia is unclear, but may involve increased enterohepatic circulation of bilirubin 2 and increased bilirubin production 4
- Fasting time has been shown to correlate positively with increased bilirubin levels in healthy males 6
Study Implications
- The findings of these studies suggest that fasting can have a significant impact on bilirubin levels, and this should be taken into account when interpreting clinical trial data 6
- The studies also highlight the importance of considering the effects of fasting on bilirubin levels in different populations, including males and females, and patients with Gilbert's syndrome 2, 4, 6