Studies on the influence of dietary cholesterol on cholesterol metabolism in the isotopic steady state in man.

Abstract

The technique of analysis utilizing the isotopic steady state was applied to assess the effect of varying cholesterol intakes on cholesterol synthesis, excretion and degradation, and absorption in man. Five balance studies were performed on 2 normal subjects who had been fed diets containing varying amounts of cholesterol-4-C14 until an isotopic steady state was attained. In protecting the human from hypercholesterolemia when cholesterol is fed, a limited ability to absorb dietary cholesterol is more important than either the inhibition of cholesterol synthesis or the acceleration of bile acid excretion. In addition, the biosynthetic origin of serum cholesterol was assessed under these circumstances; approximately 60 to 80% of the serum cholesterol is derived from endogenous sources when a diet high in cholesterol is fed.