Increases in plasma plant sterols stabilize within four weeks of plant sterol intake and are independent of cholesterol metabolism

Abstract

Background and aims: Plant sterols (PS) lower plasma LDL-cholesterol through partial inhibition of intestinal cholesterol absorption. Although PS themselves are poorly absorbed, increased intakes of PS result in elevated plasma concentrations. In this paper, we report time curves of changes in plasma PS during 12 weeks of PS intake. Furthermore, the impact of cholesterol synthesis and absorption on changes in plasma PS is explored.

Methods and results: The study was a double-blind, randomized, placebo-controlled, parallel-group study with the main aim to investigate the effects of PS on vascular function (clinicaltrials.gov: NCT01803178). Hypercholesterolemic but otherwise healthy men and women (n = 240) consumed low-fat spreads without or with added PS (3 g/d) for 12 weeks after a 4-week run-in period. Blood sampling was performed at week 0, 4, 8 and 12. Basal cholesterol-standardized concentrations of lathosterol and sitosterol + campesterol were used as markers of cholesterol synthesis and absorption, respectively. In the PS group, plasma sitosterol and campesterol concentrations increased within the first 4 weeks of intervention by 69% (95%CI: 58; 82) starting at 7.2 μmol/L and by 28% (95%CI: 19; 39) starting at 11.4 μmol/L, respectively, and remained stable during the following 8 weeks. Placebo-corrected increases in plasma PS were not significantly different between high and low cholesterol synthesizers (P-values >0.05). Between high and low cholesterol absorbers, no significant differences were observed, except for the cholesterol-standardized sum of four major plasma PS (sitosterol, campesterol, brassicasterol and stigmasterol) showing larger increases in low absorbers (78.3% (95%CI: 51.7; 109.5)) compared to high absorbers (40.8% (95%CI: 19.9; 65.5)).

Conclusions: Increases in plasma PS stabilize within 4 weeks of PS intake and do not seem impacted by basal cholesterol synthesis or absorption efficiency. This study was registered at clinicaltrials.gov (NCT01803178).

Keywords: Absorption; Cholesterol; Plant sterols; Synthesis; Time curves.

Copyright © 2015 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.