Background: The cholesterol-lowering efficacy of plant sterol esters (PSteE) or stanol esters (PStaE) in regular- and low-fat spreads has been consistently demonstrated, while their effectiveness in a low-fat, aqueous food carrier such as milk and yoghurt is less well established.
Aim of the study: Two studies were carried out to assess the cholesterol-lowering effect of PSteE-enriched low-fat milk and PSteE- and PStaE-enriched low-fat yoghurt in modestly hypercholesterolemic subjects (total cholesterol between 5-7.5 mmol/l).
Methods: Study one was a single blind crossover design with 4 phases of 3-week interventions. Subjects consumed 300 ml/d of placebo or PSteE-milk (2.0 g plant sterols/d) alone or combined with 25 g/d of placebo or PSteE-spread. Study two was a fully randomised, double blind crossover design with 3 phases of 3-week interventions. Subjects consumed 2 portions (150 g tubs each) of placebo, PSteE-yoghurt (1.8 g plant sterols/d) or PStaE-yoghurt (1.7 g plant stanols/d). In study one 39 subjects (21 men and 18 women) and in study two 40 subjects (17 men and 23 women) completed the dietary intervention.
Results: In study one, PSteE-milk and PSteE-spread were equally efficacious in lowering total and LDL-cholesterol as compared to placebo by 6-8% and 8-10%, respectively. No significant additional cholesterol-lowering was observed with the combination of PSteE-milk and PSteE-spread (4 g plant sterols/d). PSteE-enriched milk and the combination of PSteE-enriched milk plus spread both lowered lipid-adjusted serum beta-carotene concentrations by 10-14% (P < 0.02),while the PSteE-rich spread alone did not significantly alter serum beta-carotene levels. In study two, the PSteE- and PStaE-enriched yoghurts reduced LDL-cholesterol significantly compared to placebo by 0.27 +/- 0.05 mmol/l (6%) and 0.23 +/- 0.05 mmol/l (5%), respectively. In both studies, there was no effect on HDL-cholesterol and triacylglycerol concentrations.
Conclusion: Plant sterols in the form of their esters when provided in lowfat milk and yoghurt are effective in lowering total and LDL-cholesterol.