Evaluation of cholesterol-lowering and antioxidant properties of sugar cane policosanols in hamsters and humans

Abstract

Atherosclerosis prevention is now a main focus of the scientific community and pharmaceutical industry. Sugar cane policosanols (SCPs) have gained increasing popularity over the last decade as a result of numerous studies conducted in Cuba that consider SCPs as a natural alternative to statin drugs. However, independent research on policosanols was not able to replicate cholesterol reductions reported by Cuban laboratories. No independent study to date has examined the cholesterol-lowering effect and antioxidant capacity of original SCPs in humans. In addition, since independent research was criticized because of the use of alternative policosanol formulations, the source and composition of policosanol mixtures are now at the core of the policosanol controversy. The aim of this thesis project was first to compare the composition and cholesterol-lowering effects of different SCP preparations in hamsters, and second to test the cholesterol-lowering efficacy, mechanism of action, and antioxidant capacity of the original Cuban SCP in hypercholesterolemic humans. In study 1, 48 male hamsters were randomly assigned to 4 groups for a period of 4 weeks: (i) non-cholesterol control, (ii) cholesterol control, (iii) original SCPs, and (iv) alternative SCPs. Hamsters were sacrificed and blood was collected at the end of the feeding period for lipid measurements. In study 2, 21 hypercholesterolemic volunteers consumed 10 mg·d–1 of SCPs or a placebo for a period of 28 days in a crossover trial. Plasma lipid levels and low-density lipoprotein (LDL) oxidation were measured at the start and end of supplementation phases. Cholesterol absorption and synthesis were assessed using a single-isotope, single-tracer technique and deuterium incorporation, respectively. There was no significant difference in cholesterol-lowering efficacy between hamsters in the original and alternative SCP groups relative to the control. Similarly, in hypercholesterolemic humans, supplementation with original SCPs did not significantly improve lipid parameters and no change in cholesterol absorption or synthesis was observed relative to the control. In vivo assessment of LDL oxidation showed no significant changes in oxidized LDL concentration relative to baseline and control. The present thesis disagrees with previous Cuban data on the cardio-protective role of SCPs in animals and humans and supports independent studies showing no cholesterol-lowering effect and no antioxidant capacity.