Cholesterol Absorption in Patients with Malabsorption

Abstract

Human cholesterol absorption is fairly difficult to measure reliably, particularly in malabsorptive states in which it could sensitively relay the magnitude of absorption disturbance. For this purpose we have measured cholesterol absorption in various clinical conditions by different methods, including the double-label procedure described recently in the rat by Zilversmith and Hughes (1974) but not yet applied to man. In this method a small dose of [¹⁴C] cholesterol was given orally (with unlabelled carrier) and simultaneously another small dose of [³H] cholesterol intravenously, the ratio of [¹⁴C/³H] in plasma cholesterol being measured serially. The absorption percentage of the oral cholesterol could be calculated by comparing the ratio, after its levelling off, with that of the labels administered. If the labels are given in divided doses with the meals of the day the results may closely represent the absorption of dietary and perhaps also of endogenous cholesterol on that day. Absorption was measured also by the oral double label method (Sodhi et al., 1974) from faecal excretion of the single oral dose, and as the difference between the isotopic and chemical measurement of faecal neutral sterols (Grundy and Ahrens, 1969).