Effects of plant sterol esters in skimmed milk and vegetable-fat-enriched milk on serum lipids and non-cholesterol sterols in hypercholesterolaemic subjects: a randomised, placebo-controlled, crossover study

Plant sterol (PS)-supplemented foods are recommended to help in lowering serum LDL-cholesterol (LDL-C). Few studies have examined the efficacy of PS-enriched skimmed milk (SM) or semi-SM enriched with vegetable fat (PS-VFM). There is also insufficient information on factors predictive of LDL-C responses to PS. We examined the effects of PS-SM (0.1% dairy fat) and PS-VFM (0.1% dairy fat plus 1.5% vegetable fat) on serum lipids and non-cholesterol sterols in hypercholesterolaemic individuals. In a placebo-controlled, crossover study, forty-three subjects with LDL-C > 1300 mg/l were randomly assigned to three 4-week treatment periods: control SM, PS-SM and PS-VFM, with 500 ml milk with or without 3.4 g PS esters (2 g free PS). Serum concentrations of lipids and non-cholesterol sterols were measured. Compared to control, LDL-C decreased by 8.0 and 7.4% (P<0.015, both) in the PS-SM and PS-VFM periods, respectively. Serum lathosterol:cholesterol (C) ratios increased by 11-25%, while sitosterol:C and campesterol:C ratios increased by 70-120% with both the PS-fortified milk. Adjusted LDL-C reductions were variably enhanced in participants with basal low serum lathosterol/C or conversely high sitosterol/C and campesterol/C. Subjects with post-treatment serum PS:C ratios above the median showed mean LDL-C changes of -5.9 to -10.4%, compared with 1.7 to -2.9% below the median. In conclusion, consumption of 2 g/d of PS as PS-SM and PS-VFM lowered LDL-C in hypercholesterolaemic subjects to a similar extent. Basal and post-treatment changes in markers of cholesterol metabolism indicating low cholesterol synthesis and high cholesterol absorption predicted improved LDL-C responses to PS.