Phytosterols (plant sterols and stanols) are well known for their LDL-cholesterol (LDL-C)-lowering effect. A meta-analysis of randomized controlled trials in adults was performed to establish a continuous dose-response relationship that would allow predicting the LDL-C-lowering efficacy of different phytosterol doses. Eighty-four trials including 141 trial arms were included. A nonlinear equation comprising 2 parameters (the maximal LDL-C lowering and an incremental dose step) was used to describe the dose-response curve. The overall pooled absolute (mmol/L) and relative (%) LDL-C-lowering effects of phytosterols were also assessed with a random effects model. The pooled LDL-C reduction was 0.34 mmol/L (95% CI: -0.36, -0.31) or 8.8% (95% CI: -9.4, -8.3) for a mean daily dose of 2.15 g phytosterols. The impacts of subject baseline characteristics, food formats, type of phytosterols, and study quality on the continuous dose-response curve were determined by regression or subgroup analyses. Higher baseline LDL-C concentrations resulted in greater absolute LDL-C reductions. No significant differences were found between dose-response curves established for plant sterols vs. stanols, fat-based vs. non fat-based food formats and dairy vs. nondairy foods. A larger effect was observed with solid foods than with liquid foods only at high phytosterol doses (>2 g/d). There was a strong tendency (P = 0.054) towards a slightly lower efficacy of single vs. multiple daily intakes of phytosterols. In conclusion, the dose-dependent LDL-C-lowering efficacy of phytosterols incorporated in various food formats was confirmed and equations of the continuous relationship were established to predict the effect of a given phytosterol dose. Further investigations are warranted to investigate the impact of solid vs. liquid food formats and frequency of intake on phytosterol efficacy.

OST DIETARY MANIPULAtions result in modest cholesterol reductions of 4% to 13%, 1-10 and diet has been considered by some as a relatively ineffective therapy. 11 In contrast, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) repeatedly have been shown to reduce mean serum low-density lipoprotein cholesterol (LDL-C) concentrations by 28% to 35% in long-term trials, [12][13][14] with corresponding reductions in cardiovascular death of 23% to 32% in both primary and secondary prevention trials. 13,14 Recently, to boost effectiveness of diet for primary prevention of cardiovascular disease, the Adult Treatment Panel (ATP III) of the National Cholesterol Education Program has recommended addition of plant sterols (2 g/d) and viscous fibers (10-25 g/d) to the diet. 15 The American Heart Association has also drawn atten-Author Affiliations and Financial Disclosures are listed at the end of this article.

Phytosterols (PS, comprising plant sterols and plant stanols) have been proven to lower LDL-cholesterol concentrations. The dose–response relationship for this effect has been evaluated in several meta-analyses by calculating averages for different dose ranges or by applying continuous dose–response functions. Both approaches have advantages and disadvantages. So far, the calculation of averages for different dose ranges has not been done for plant sterols and stanols separately. The objective of the present meta-analysis was to investigate the combined and separate effects of plant sterols and stanols when classified into different dose ranges. Studies were searched and selected based on predefined criteria. Relevant data were extracted. Average LDL-cholesterol effects were calculated when studies were categorised by dose, according to random-effects models while using the variance as weighing factor. This was done for plant sterols and stanols combined and separately. In total, 124 studies (201 strata) were included. Plant sterols and stanols were administered in 129 and fifty-nine strata, respectively; the remaining used a mix of both. The average PS dose was 2·1 (range 0·2–9·0) g/d. PS intakes of 0·6–3·3 g/d were found to gradually reduce LDL-cholesterol concentrations by, on average, 6–12 %. When plant sterols and stanols were analysed separately, clear and comparable dose–response relationships were observed. Studies carried out with PS doses exceeding 4 g/d were not pooled, as these were scarce and scattered across a wide range of doses. In conclusion, the LDL-cholesterol-lowering effect of both plant sterols and stanols continues to increase up to intakes of approximately 3 g/d to an average effect of 12 %.

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