Elsevier

Metabolism

Volume 57, Issue 1, January 2008, Pages 130-139
Metabolism

Effect of plant sterols in combination with other cholesterol-lowering foods

https://doi.org/10.1016/j.metabol.2007.08.016Get rights and content

Abstract

The National Cholesterol Education Program Adult Treatment Panel III guidelines advocate effective combinations of cholesterol-lowering dietary components. This approach (dietary portfolio) produces large reductions in serum cholesterol, but the contribution of individual components remains to be established. We therefore assessed the effect of eliminating one out of the 4 dietary portfolio components. Plant sterols were selected because at 2 g/d, they have been reported to reduce low-density lipoprotein cholesterol (LDL-C) by 9% to 14%. Forty-two hyperlipidemic subjects were prescribed diets high in soy protein (22.5 g/1000 kcal), viscous fibers (10 g/1000 kcal), and almonds (23 g/1000 kcal) for 80 weeks. Subjects were instructed to take these together with plant sterols (1.0 g/1000 kcal) except between weeks 52 and 62. While taking the full dietary portfolio, including plant sterols, mean LDL-C reduction from baseline was 15.4% ± 1.6% (P < .001). After sterol elimination, mean LDL-C reduction was 9.0% ± 1.5% (P < .001). Comparable LDL-C reductions were also seen for the 18 subjects with a complete data set: on plant sterols, 16.7% ± 3.1% (P < .001) and off plant sterols, 10.3% ± 2.6% (P < .001), resulting in a 6.3% ± 2.0% (P = .005) difference attributable to plant sterols. Compliance in this group of 18 was 67.0% ± 5.9% for plant sterols and 61.9% ± 4.8% for the other components. In combination with other cholesterol-lowering foods and against the background of a low–saturated fat diet, plant sterols contributed over one third of the LDL-C reduction seen with the dietary portfolio after 1 year of following dietary advice.

Introduction

The National Cholesterol Education Program Adult Treatment Panel III (ATP III) guidelines have emphasized the principle of maximal therapy for the management of low-density lipoprotein cholesterol (LDL-C) through adding viscous fibers and plant sterols to the original advice on reduction of saturated fat, dietary cholesterol, and body weight as the dietary prescription [1]. With these dietary changes, it has been estimated that 25% to 35% reductions in LDL-C can be achieved [2], [3]. The importance of maximizing cholesterol reduction has been further stressed in the ATP III update that, based on the success of statin trials in reducing coronary heart disease (CHD), advocates treating to a new optional target for LDL-C of less than 100 mg/dL (1.8 mmol/L) in high-risk subjects [4]. The United States Food and Drug Administration has also encouraged the development of cholesterol-lowering functional foods by allowing CHD risk reduction health claims for products containing plant sterols, viscous fibers, soy protein, and nuts [5], [6], [7], [8], [9]. Diets containing these elements have confirmed predicted lipid-lowering effects of 28% to 35% in LDL-C when they are combined in the same diet in what has been termed a dietary portfolio[10], [11], [12], [13].

However, it is not clear what cholesterol reduction each functional food component contributes to the overall cholesterol reduction observed and whether all ingredients have to be present.

We have therefore taken the opportunity to remove one element, plant sterols, from the diets of individuals who have been taking the combination diet (dietary portfolio) for 1 year to determine its effects on the previously observed reduction in serum cholesterol. Plant sterols were selected because they represent the component with possibly the largest effect, with 2 g resulting in 9% to 14% reduction in LDL-C [14], and for which more data are available than the other components.

Section snippets

Participants

Fifty-five subjects completed a 1-year ad libitum dietary portfolio study and were asked to forgo consumption of plant sterol–enriched margarine for 10 weeks, after which they were asked to continue for a further 18 weeks with plant sterol–enriched margarine reinstated in their diets. Forty-nine subjects were enrolled in the present study. Forty-two provided data on and off plant sterols, of whom 18 followed the protocol with no deviation in terms of complete attendance and diet records. Data

Results

For the 42 subjects, compliance for plant sterol–enriched margarine was 65.8% ± 4.3%, whereas for the non–plant sterol components (ie, viscous fiber, soy protein, and almonds), the combined compliance was 52.0% ± 3.7%. No significant change in the compliance of the non–plant sterol components was seen when plant sterol margarine was removed from the diet (combined compliance after plant sterol elimination was 49.9% ± 4.0%, P = .281). In the 18 subjects who adhered most completely to the study

Discussion

Plant sterol withdrawal from a cholesterol-lowering diet resulted in a reduction in the overall cholesterol-lowering effect of the diet of similar magnitude to that ascribed to plant sterols when administered as the sole cholesterol-lowering component. However, in compliant subjects, even when not consuming plant sterol–enriched margarine, substantial reductions in serum cholesterol can still be achieved through good adherence to the other components of the dietary portfolio.

Meta-analyses and

Acknowledgments

The authors wish to thank Mrs Kathy Galbraith for her assistance on this project and the study participants for their enthusiasm and attention to detail. This study was supported by the Canada Research Chair Endowment of the Federal Government of Canada; the Canadian Natural Sciences and Engineering Research Council of Canada; Loblaw Brands Limited; the Almond Board of California; and Unilever Canada and Unilever Research & Development, Vlaardingen, the Netherlands.

Authors’ contributions—Study

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