Proposed mechanisms of cholesterol‐lowering action of plant sterols

Abstract

The aim of this review is to summarise the current understanding concerning the mechanism of action by which plant sterols affect cholesterol metabolism and thus exert their cholesterol-lowering effect. The review will focus on the gut, e.g. on the physico-chemical effects at the gastric-duodenal level, on absorptive site effects, and on intra-cellular trafficking, i.e. effects at the epithelial cell level.

Intake occasion affects the serum cholesterol lowering of a plant sterol-enriched single-dose yoghurt drink in mildly hypercholesterolaemic subjects

“…The digestion of food is linked to fat emulsification with the help of bile and pancreatic enzymes. PS esters are involved in this process and thus interact with the micellar cholesterol from both dietary and endogenous sources (Rigler et al, 1986;Evans and Wennerström, 1994;Ostlund, 2002;Trautwein et al, 2003;Mel'nikov et al, 2004). A reduction of the cholesterol content in dietary mixed micelles due to a dynamic competition between cholesterol and PS for the micellar solubilization is an important part of the overall mechanisms of action of PS.…”

“…Both mechanisms together seem essential for an optimal situation for PS to interact with micellar cholesterol over time and consequently for maximal displacement of dietary and biliary cholesterol from the micellar phase. As a consequence, the intestinal cholesterol absorption will be more efficiently reduced and hence more cholesterol will be excreted in the faeces (Trautwein et al, 2003). Also, it cannot be fully ruled out that differences in cholesterol intake with meals could have influenced the observed effects.…”

“…The classical suggested mechanism of action is displacement of cholesterol from the micellar phase. As there is limited capacity in dietary mixed micelles to embody PS, the micellar concentration of cholesterol is reduced and, hence, its transport towards the intestinal brush border membrane is decreased (Trautwein et al, 2003;Mel'nikov et al, 2004). Further, stimulation of bile flow as a response to fatty food intake seems crucial in view of the formation of dietary mixed micelles and thus plays a critical role in the overall mechanism of action and consequently also for the cholesterol-lowering potential of PS when consumed with various background diets and as different enriched food formats.…”

Dose-response effects of different plant sterol sources in fat spreads on serum lipids and C-reactive protein and on the kinetic behavior of serum plant sterols

“…The typical differences in PS composition from these sources could possibly influence the cholesterol-lowering efficacy or metabolic handling of the sterol. PS themselves are absorbed to minor degree, although the main site of action remains in the gut (Trautwein et al, 2003), whereas stanols, the fully hydrogenated form of sterols, are absorbed to a much lower extent (Ostlund et al, 2002). Results of different studies, testing whether sterol/ stanol mixtures influence each others absorption or excretion or metabolic effects are not conclusive (Normén et al, 2000;Nestel et al, 2001;Naumann et al, 2003).…”

Conjugated and free sterols from black bean (Phaseolus vulgaris L.) seed coats as cholesterol micelle disruptors and their effect on lipid metabolism and cholesterol transport in rat primary hepatocytes

“…Studies with the free forms of phytosterols related to their cholesterol-lowering effects have only been addressed toward the reduction in cholesterol absorption (Carr 2002;Guderian et al 2007; Lee et al 2012;Rasmussen et al 2006;Trautwein and Duchateau 2003). One of the proposed mechanisms for the interference of cholesterol intestinal absorption is the inhibition of micellar solubility (Jesch and Carr 2006;Trautwein and Duchateau 2003).…”