Plant sterols/stanols as cholesterol lowering agents: a meta-analysis of randomized controlled trials

Abstract

Background: Consumption of plant sterols has been reported to reduce low density lipoprotein (LDL) cholesterol concentrations by 5 to 15%. Factors that affect plant sterol efficacy are still to be determined. Objective: To more precisely quantify the effect of plant sterols on LDL cholesterol concentrations in humans and to look into factors that affect plant sterols efficacy. Design: Fifty nine eligible randomized clinical trials published from 1992 to 2006 were identified from five databases. Weighted mean effect sizes were calculated for net differences in LDL levels using a random effect model (RevMan 4.2). Results: Plant sterol containing products decreased LDL levels by 0.31 mmol/L (95% CI, -0.35 to -0.27, P= < 0.0001) compared with placebo. Between trial heterogeneity was evident (Chi 2 test, P= < 0.0001) indicating that the observed differences between trial results were unlikely to have been caused by chance. Reductions in LDL levels were greater in individuals with high baseline LDL levels compared with those with normal to borderline baseline LDL levels. Reductions in LDL were greater when plant sterols were incorporated into fat spreads, mayonnaise and salad dressing, milk and yoghurt comparing with other food products such as croissants and muffins, orange juice, non fat beverages, cereal bars, and chocolate. Plant sterols consumed as a single morning dose did not have a significant effect on LDL cholesterol . Conclusion: This is the first meta-analysis that resolves the controversy concerning the influence of food matrix and frequency and time of intake of plant sterols, as well as subjects’ baseline characteristics, on cholesterol-lowering efficacy of plant sterols.

Keywords: meta-analysis; plant sterols; LDL cholesterol; intake frequency; single dose; food carrier

(Published online: 18 August, 2008)

Citation: Food & Nutrition Research 2008. DOI: 10.3402/fnr.v52i0.1811