Fat absorption and metabolism.

This review spans almost 20 years during which the author's initial interest in the hypolipidaemia of patients with steatorrhoea eventually led him to treat hyperlipidaemia by deliberately inducing malabsorption of cholesterol and bile acids. Before discussing malabsorption, however, it is necessary to first consider the normal physiology of fat absorption and metabolism. This process can be divided into various phases as summarised below: The intraluminal phase, involves lipolysis and micellar solubilisation of dietary fat; The mucosal phase, involves uptake of micellar lipids and their subsequent re-esterification; The lymphatic phase, involves chylomicron formation and secretion into lymph; and The catabolic phase, which involves the peripheral hydrolysis of chylomicrons, the uptake of remnant particles by the liver and the subsequent recycling and exchange of lipids and apoproteins among the various plasma lipoproteins.