Both free and esterified plant sterols reduce cholesterol absorption and the bioavailability of beta-carotene and alpha-tocopherol in normocholesterolemic humans.
BACKGROUND
Plant sterols reduce cholesterol absorption, which leads to a decrease in plasma and LDL-cholesterol concentrations. Plant sterols also lower plasma concentrations of carotenoids and alpha-tocopherol, but the mechanism of action is not yet understood.


OBJECTIVE
The aims of this clinical study were to determine whether plant sterols affect the bioavailability of beta-carotene and alpha-tocopherol in normocholesterolemic men and to compare the effects of plant sterol esters and plant free sterols on cholesterol absorption.


METHODS
Twenty-six normocholesterolemic men completed the double-blind, randomized, crossover study. Subjects consumed daily, for 1 wk, each of the following 3 supplements: a low-fat milk-based beverage alone (control) or the same beverage supplemented with 2.2 g plant sterol equivalents provided as either free sterols or sterol esters. During this 1-wk supplementation period, subjects consumed a standardized diet.


RESULTS
Both of the milks enriched with plant sterols induced a similar (60%) decrease in cholesterol absorption. Plant free sterols and plant sterol esters reduced the bioavailability of beta-carotene by approximately 50% and that of alpha-tocopherol by approximately 20%. The reduction in beta-carotene bioavailability was significantly less with plant free sterols than with plant sterol esters. At the limit of significance (P = 0.054) in the area under the curve, the reduction in alpha-tocopherol bioavailability was also less with plant free sterols than with plant sterol esters.


CONCLUSIONS
Both plant sterols reduced beta-carotene and alpha-tocopherol bioavailability and cholesterol absorption in normocholesterolemic men. However, plant sterol esters reduced the bioavailability of beta-carotene and alpha-tocopherol more than did plant free sterols.
Richelle
Myriam
M
Nestlé Research Center, Nestec Ltd, Lausanne, Switzerland. myriam.richelle@rdls.nestle.com
Enslen
Marc
M
Hager
Corinne
C
Groux
Michel
M
Tavazzi
Isabelle
I
Godin
Jean-Philippe
JP
Berger
Alvin
A
Métairon
Sylviane
S
Quaile
Sylvie
S
Piguet-Welsch
Christelle
C
Sagalowicz
Laurent
L
Green
Hilary
H
Fay
Laurent Bernard
LB
D000328:Adult; D000975:Antioxidants / Q000493:pharmacokinetics; D019540:Area Under Curve; D001682:Biological Availability; D002784:Cholesterol / Q000097:blood* / Q000493:pharmacokinetics*; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D004224:Diterpenes; D004311:Double-Blind Method; D004952:Esters; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D010840:Phytosterols / Q000494:pharmacology*; D000084562:Retinyl Esters; D014801:Vitamin A / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D024502:alpha-Tocopherol / Q000493:pharmacokinetics*; D019207:beta Carotene / Q000493:pharmacokinetics*
D000975:Antioxidants; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004224:Diterpenes; D004952:Esters; D010840:Phytosterols; D000084562:Retinyl Esters; D019207:beta Carotene; D014801:Vitamin A; C014794:retinol palmitate; D002784:Cholesterol; D024502:alpha-Tocopherol