Interrelationship between serum and fecal sterols.

Area of Science:

• Gastroenterology
• Microbiology
• Metabolic Research

Background:

• Dietary cholesterol intake and fecal sterol excretion vary significantly among individuals.
• Intestinal microflora play a role in sterol metabolism.

Purpose of the Study:

• To investigate the relationship between intestinal flora activity, fecal sterol composition, and serum cholesterol levels.
• To determine the role of cholesterol conversion to coprostanol by gut bacteria in cholesterol regulation.

Main Methods:

• Dietary intervention with controlled cholesterol intake (359 mg/day) in healthy volunteers and hospitalized patients.
• Analysis of fecal cholesterol and coprostanol levels, including the coprostanol/cholesterol ratio.
• In vitro anaerobic incubation of feces with egg yolk to assess intestinal flora activity.
• Measurement of de novo cholesterol synthesis.
• Determination of fecal sterol amounts in additional hospitalized patients.

Main Results:

• Significant inter-individual variation in fecal cholesterol and coprostanol excretion was observed (coprostanol/cholesterol ratio: 0.01–4.27).
• Lower coprostanol excretion was associated with higher beta-sitosterol and crude fiber excretion, indicating reduced intestinal flora activity.
• An inverse relationship was found between serum cholesterol levels and the fecal coprostanol/cholesterol ratio in hospitalized patients.
• De novo cholesterol synthesis ranged from 0.1–0.6 g/day.

Conclusions:

• Intestinal flora's conversion of cholesterol to coprostanol varies significantly among individuals.
• This conversion process may be a crucial factor in regulating serum cholesterol levels.
• Gut microbial activity in sterol metabolism represents a potential therapeutic target for managing hypercholesterolemia.