Role of Xenosterols in Health and Disease

Abstract Xenosterols are important non-nutritional dietary compounds that are found in non-animal foods in which phytosterols comprise the larger group of these sterols. Under normal physiological conditions, dietary xenosterol levels are present in blood at barely detectable levels. Patients with an autosomal recessive disease, Sitosterolemia, show accumulations of very high amounts of these xenosterols, in which sitosterol is the most abundant species hence the name. Mutations in ATP (adenosine triphosphate) Binding Cassette transporters G5 and G8 (ABCG5 and ABCG8) are responsible for causing this disease; sterolins ABCG5/G8 function as obligate heterodimers to efficiently efflux xenosterols out at the intestinal and biliary-tree levels to normally maintain a low systemic exposure to these dietary xenosterols. This chapter will focus on reviewing the importance of xenosterols in health and disease; discuss their significance in the pathogenesis of Sitosterolemia and the current knowledge on their impact in the management of cardiovascular (CVS) and central nervous disorders (CNS).