High dietary intake of phytosterol esters decreases carotenoids and increases plasma plant sterol levels with no additional cholesterol lowering

Abstract

The objective of this study was to measure the effects on serum lipids and plasma phytosterols of 6.6 g/day phytosterols from three foods (bread, breakfast cereal, and spread) consumed for 12 weeks compared with a diet that was not enriched with phytosterols. Thirty-five subjects undertook a nonrandomized, single-blind study consisting of a 2 week baseline period, 6 weeks on high-phytosterol intake, 6 weeks on high-phytosterol intake plus increased fruit and vegetable intake, and a final 2 week washout period. Serum total cholesterol decreased by 8.3% from 6.59 to 6.04 mmol/l, and LDL cholesterol decreased by 12.6% from 4.44 to 3.88 mmol/l. Plasma phytosterol levels increased by 45% (sitosterol) and 105% (campesterol). Cholesterol-adjusted plasma ␣ -and ␤ -carotene levels decreased by 19-23%, lutein by 14%, and lycopene by 11%. Levels of ␣ -carotene and lutein increased with extra fruit and vegetables. Only lycopene failed to increase during the washout phase. There were no significant changes in biochemical parameters. Serum LDL cholesterol lowering with 6.6 g/day ingested phytosterols was in the range seen with 1.6-3.2 g/day phytosterols. Lowering of plasma carotenoids was greater than that seen with lower phytosterol intake and was partially reversed by increased fruit and vegetable intake. There are extensive data confirming the effectiveness of esterified phytosterols in margarines, with LDL cholesterol lowering of 10-15% with a dose of 1.6-2.4 g/day sterol (1-6). There are few published data (7, 8) on the short-term use of higher amounts of plant sterols (8.6-9 g/day) in margarines, and there is some evidence that carotenoid lowering is greater on a high dose of phytosterol without enhancement of cholesterol lowering (7). It is not known if increased fruit and vegetables can restore the plasma level of carotenoids after a higher intake of phytosterols, although they can achieve this with a more usual intake of phytosterols (4). The aim of this study was to examine the effect of 6.6 g/day phytosterols in bread, breakfast cereals, and margarine over a 12 week period, to examine the role of extra fruit and vegetables in ameliorating the decrease in carotenoid concentration, and to examine the changes in carotenoid concentrations after cessation of phytosterol ingestion. METHODS SubjectsThirty-five mildly hypercholesterolemic men and women were recruited and entered the study. The study was conducted at two clinical research centers: the Commonwealth Scientific and Industrial Research Organization (CSIRO) Division of Health Sciences and Nutrition in Adelaide and the Baker Medical Research Institute in Melbourne. Subjects were screened on the basis of the following inclusion criteria: age, 20-75 years; body mass index (BMI), Ͻ 31; total serum cholesterol, Ͼ 5.0 mmol/l and Ͻ 7.5 mmol/l; and serum triglycerides, Ͻ 4.5 mmol/l. No lipid-lowering medication was permitted, nor was medication likely to affect lipid metabolism. Subjects were not diabetic, had normal thyroid status, and had no metabolic disorde...

Lipid-lowering Activity of Natural and Semi-Synthetic Sterols and Stanols

“…Similar changes were reported in rats treated with high doses of stanol ester for 13 weeks (156). However, when the levels of these vitamins were adjusted to the lowered LDL-C concentrations, the reduction was not significant for vitamin E, D and K (9, 41, 106), while plasma levels of α-, β -carotene and lycopene remained low (9,41,153,157). The effects of plant sterols on fat soluble vitamins can be overcome by maintaining adequate daily intake of fruits and vegetables (1,9,158).…”

“…Few clinical trials have shown that the use of high doses of plant sterols/ stanols was associated with a modest reduction in levels of carotenoids, fat-soluble vitamins and antioxidants (40,94,(153)(154)(155). Similar changes were reported in rats treated with high doses of stanol ester for 13 weeks (156).…”

Baseline plasma plant sterol concentrations do not predict changes in serum lipids, C-reactive protein (CRP) and plasma plant sterols following intake of a plant sterol-enriched food

“…In a crossover trial supplementation with 1.8 g per day of PS to 63 healthy individuals elevated plasma campesterol plus sitosterol concentrations from 9.0 to 16.6 mmol l À1 and 4.4 to 6.0 mmol l À1 (Mussner et al, 2002). Clifton et al (2004) showed that supplementation with a larger dose of 6.6 g per day in 35 mildly hypercholesterolemic subjects increased campesterol and sitosterol concentrations to a similar extent (7.8-15.8 and 8.0-11.4 mmol l À1 , respectively). No studies thus far, however, have considered the extent to which PS intake elevates concentrations of plasma campesterol and sitosterol as a function of natural circulating levels as was done presently.…”

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 concentrations of the individual sterols in serum were quantified using a modified method as described previously by Wolthers et al (1991). The method was based on saponification followed by extraction, silylation and analysis by gas chromatography with flame ionization detection (GC-FID) using an internal standard for calibration as described previously (Clifton et al, 2004). All analyses were performed on an Agilent 6890N GC equipped with an on-column injector (Agilent Technologies, Sydney, Australia).…”