Cholesterol absorption: regulation of cholesterol synthesis and elimination and within-population variations of serum cholesterol levels.

Obesity and dietary plant sterols were negatively associated with fractional absorption of dietary cholesterol in a random population of 63 middle-aged men. Absorbed dietary cholesterol increased linearly with the increase of dietary cholesterol intake. The higher the fractional and absolute absorption of dietary cholesterol the lower the rates of biliary secretion, fecal elimination, and cholesterol synthesis. The findings also revealed that high serum levels of total, LDL, and HDL cholesterol were associated with high cholesterol absorption and that of HDL cholesterol was associated also with low synthesis and fecal elimination of cholesterol. Thus, cholesterol absorption efficiency and absorbed dietary cholesterol significantly regulate cholesterol synthesis and elimination and are important determinants of within-population variation in the serum levels of total, LDL, and HDL cholesterol.