Effects of plant sterol-or stanol-enriched margarine on fasting plasma oxyphytosterol concentrations in healthy subjects

Background: Consumption of plant sterols and plant stanols reduces low-density lipoprotein cholesterol (LDL-C) concentrations. At the same time, plasma plant sterol concentrations will increase after plant sterol consumption, but decrease after plant stanol consumption. In contrast to plant stanols, plant sterols can undergo oxidation and form oxyphytosterols. Findings from in vitro and animal studies suggest that oxyphytosterols might be atherogenic. Objective: The objective was to examine whether plant sterol and stanol consumption changes fasting plasma oxyphytosterol concentrations. Design: A randomized, double blind, cross-over study was performed in which 43 healthy subjects (18-70 years) consumed for 4 weeks a plant sterol-enriched (3.0 g/d of plant sterols), a plant stanol-enriched (3.0 g/d of plant stanols), and a control margarine separated by wash-out periods of 4 weeks. Oxyphytosterol concentrations were determined in BHT-enriched plasma via GC-MS. Results: Compared to control, serum LDL-C concentrations were reduced after plant sterol (-8.1%; p < 0.001) and plant stanol consumption (-7.8%; p < 0.001). Plant sterol consumption did not change plasma oxyphytosterol concentrations. On the other hand, intake of the plant stanol margarine reduced 7 beta-OH-campesterol by 0.07 ng/mL (similar to 14%; p < 0.01) and by 0.07 ng/mL (similar to 15%; p < 0.01) compared with the control and sterol margarines, respectively. When standardized for serum cholesterol, effects on these oxyphytosterols were comparable. In addition, plant stanol intake reduced cholesterol-standardized 7-keto-campesterol levels compared with plant sterol intake (p < 0.05). Conclusions: Daily consumption of a plant sterol-enriched margarine does not increase oxyphytosterol concentrations, while plant stanol consumption may reduce the concentrations of the oxidative plant sterol metabolites 7 beta-OH-campesterol and 7-keto-campesterol. This trial is registered at clinicaltrials.gov as NCT01559428. (C) 2013 Elsevier Ireland Ltd. All rights reserved.