Iron deficiency enhances cholesterol gallstone formation

Area of Science:

• Hepatology
• Nutritional Science
• Gastroenterology

Background:

• Cholesterol gallstones are common in multiparous women, but the underlying causes are not fully understood.
• This demographic also experiences high rates of chronic iron deficiency anemia.
• Iron is recognized for its role in hepatic enzyme metabolism, prompting investigation into its connection with gallstone formation.

Purpose of the Study:

• To investigate the hypothesis that iron deficiency alters hepatic cholesterol metabolism.
• To determine if iron deficiency enhances cholesterol gallstone formation.

Main Methods:

• Prairie dogs were fed diets varying in iron content (deficient vs. supplemented) and cholesterol levels for 8 weeks.
• Gallbladder bile, serum, and liver were analyzed for cholesterol crystals, gallstones, bile lipids, and hepatic enzymes.
• Cholesterol saturation index (CSI) was calculated to assess bile's capacity to dissolve cholesterol.

Main Results:

• Iron-deficient diets significantly increased cholesterol crystals in bile compared to control diets (80% vs. 20%).
• Diets with both high cholesterol and iron deficiency led to higher cholesterol crystal counts, molar percentage of cholesterol, and CSI.
• Lower 7 alpha-hydroxylase enzyme levels were observed in iron-deficient animals, indicating altered hepatic metabolism.

Conclusions:

• Iron deficiency alters hepatic enzyme metabolism, leading to increased cholesterol in gallbladder bile.
• This metabolic alteration promotes cholesterol crystal formation, suggesting a role for iron deficiency in cholesterol gallstone pathogenesis.
• The findings highlight a previously unrecognized contribution of iron deficiency to gallstone formation in women.