¹Department of Human Nutrition, University of Otago, Dunedin, New Zealand

Correspondence: Dr C M Skeaff, Department of Human Nutrition, University of Otago, PO Box 56, Dunedin, New Zealand. E-mail: murray.skeaff@stonebow.otago.ac.nz

^*Guarantor: Dr CM Skeaff.

^†Contributors: CLC conducted the dietary intervention, carried out the laboratory analysis, completed statistical analyses and produced the first draft of the paper. CMS was involved in obtaining funding, the concept and planning of the study, the overall supervision of the project and the writing of the final draft of the paper. JM was involved in obtaining funding, the concept and planning of the study and the writing of the final draft. AC was involved in the design of the diets, conducting the dietary intervention, and approving the manuscript.

Received 23 January 2002; Revised 1 May 2002; Accepted 16 May 2002.

Abstract

Objective: To determine the effect of a plant sterol-enriched spread on plasma cholesterol concentrations when replacing butter or a standard polyunsaturated spread in a diet containing 30% of energy fat.

Design: Parallel butter phase followed by double-blind, randomized, cross-over polyunsaturated spread phases.

Setting: General community.

Subjects: Volunteer sample of 50 free-living men and women with mean age (s.d.) 46.7 y (10.5), moderately elevated plasma total cholesterol 5.95 mmol/l (0.78), and body mass index 26.0 (3.9) kg/m².

Intervention: Participants ate a moderately low-fat diet (30% of energy) for the 11-week intervention. During the first 3 weeks the diet included 20 g per day of butter. Participants were then randomized to replace the butter with 25 g of polyunsaturated spread with or without 2 g of plant sterols for 4 weeks, crossing over in the last 4 weeks to the alternate spread.

Main outcome measures: Plasma cholesterol and fatty acids.

Results: Replacing butter with a standard polyunsaturated fat spread reduced mean plasma total cholesterol concentrations by 4.6% (from 6.09 (0.82) to 5.81 (0.77) mmol/l, P<0.01) and low-density lipoprotein cholesterol by 5.5% (from 3.98 (0.76) to 3.76 (0.74) mmol/l, P<0.05). Replacing butter with a polyunsaturated spread containing plant sterols reduced plasma total cholesterol by 8.9% (from 6.09 (0.82) to 5.55 (0.76) mmol/l, P<0.01) and low density lipoprotein cholesterol by 12.3% (from 3.98 (0.76) to 3.49 (0.72) mmol/l, P<0.01). Plasma high density lipoprotein cholesterol concentration was the same on the three diets.

Conclusion: In people with moderately raised plasma cholesterol concentrations consuming reduced-fat diets the reduction in plasma total and low-density lipoprotein cholesterol concentrations achieved by replacing butter with a polyunsaturated spread is enhanced by addition of plant sterols.

Sponsorship: Partially funded by a grant to the University of Otago from Unilever Research.