The Comparative Efficacy of Plant Sterols and Stanols on Serum Lipids: A Systematic Review and Meta-Analysis

Background: Plant sterols and stanols are plant steroids with a similar chemical structure and cellular function to human cholesterol, and are recommended as dietary modifiers of serum lipids. Plant sterols have a higher degree of absorption than plant stanols, suggesting differential efficacy between the two. Design: A meta-analysis of randomized controlled trials was performed to summarize direct comparisons between the effect of plant sterols vs plant stanols on serum lipid levels in healthy patients and patients with hypercholesterolemia. Methods: A systematic literature search of MEDLINE, EMBASE, Cochrane CENTRAL, and the Natural Medicines Comprehensive Database was conducted from January 1950 through January 2009. Trials were included in the analysis if they were randomized controlled trials evaluating the effect of plant sterols vs plant stanols in healthy patients or patients with hypercholesterolemia who reported efficacy data on total, low-density lipoprotein, and high-density lipoprotein cholesterols or triglycerides. The weighted mean difference (WMD) of the change from baseline (in mg/dL) with 95% confidence interval was calculated as the difference between the means in the plant sterol and plant stanol groups using a random-effects model. Results: Fourteen studies (n=531 patients) met the inclusion criteria. Upon meta-analysis, the results showed that there is no statistically or clinically significant difference between plant sterols and plant stanols in their abilities to modify total cholesterol (WMD −1.11 mg/dL [−0.0286 mmol/L], 95% confidence interval [CI] −4.12 to 1.90, P=0.47), low-density lipoprotein cholesterol (WMD −0.35 mg/dL [−0.0091 mmol/L], 95% CI −2.98 to 2.28, P=0.79), high-density lipoprotein cholesterol (WMD −0.28 mg/dL [-0.00073 mmol/L], 95% CI −1.18 to 0.62, P=0.54), or triglycerides (WMD −1.80 mg/dL [−0.0203 mmol/L], 95% CI −6.80 to 3.21, P=0.48). Conclusions: Plant sterols and plant stanols do not have statistically or clinically relevant differing effects on total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or triglyceride levels. The selection of plant sterols vs plant stanols should then be based on potential differences in safety parameters and further study is required to elucidate such differences.