Continuous dose-response relationship of the LDL-cholesterol-lowering effect of phytosterol intake

Plant stanol esters lower serum triacylglycerol concentrations via a reduced hepatic VLDL-1 production

Plant stanol esters not only lower low density lipoprotein cholesterol but also have previously been shown to lower serum triacylglycerol (TAG) concentrations, especially in subjects with elevated TAG concentrations. To find a possible explanation, we explored changes in serum lipoprotein profiles, as measured with nuclear magnetic resonance. For this, serum samples from two parallel-designed controlled studies were evaluated before and 8 weeks after the consumption of plant stanol esters. In the first study, dyslipidemic metabolic syndrome subjects participated and in the second study normolipidemic subjects. In metabolic syndrome subjects, plant stanol esters lowered concentrations of large (>60 nm) and medium (35–60 nm) VLDL particles as compared to controls. In normolipidemic subjects, the serum concentration of large VLDL-1 particles was also lowered, although less pronounced. Based on these findings, we hypothesize that the effect of plant stanol esters on serum TAG concentrations origins from a lowered hepatic production of large TAG-rich VLDL-1 particles.

Low and moderate-fat plant sterol fortified soymilk in modulation of plasma lipids and cholesterol kinetics in subjects with normal to high cholesterol concentrations: report on two randomized crossover studies

Background

Although consumption of various plant sterol (PS)-enriched beverages is effective in lowering plasma cholesterol, the lipid-lowering potential of PS in a soymilk format has not been investigated thoroughly. Therefore, to evaluate the efficacy of PS-enriched soy beverages on plasma lipids and cholesterol kinetics, we conducted two separate 28 d dietary controlled cross-over studies. In study 1, the cholesterol-lowering efficacy of a low-fat (2 g/serving) PS enriched soy beverage was examined in 33 normal cholesterolemic subjects in comparison with 1% dairy milk. In study 2, we investigated the efficacy of a moderate-fat (3.5 g/serving) PS-enriched soy beverage on plasma cholesterol concentrations and cholesterol kinetic responses in 23 hypercholesterolemic subjects compared with 1% dairy milk. Both the low and moderate-fat PS-enriched soymilk varieties provided 1.95 g PS/d. Endpoint plasma variables were analyzed by repeated-measures ANOVA using baseline values as covariates for plasma lipid measurements.

Results

In comparison with the 1% dairy milk control, the low-fat soy beverage reduced (P < 0.05) total and LDL-cholesterol by 10 and 13%, respectively. Consumption of the moderate-fat PS-enriched soy beverage reduced (P < 0.05) plasma total and LDL-cholesterol by 12 and 15% respectively. Fasting triglycerides were reduced by 9.4% following consumption of the moderate-fat soy beverage in comparison with the 1% dairy milk. Both low and moderate-fat PS-enriched soy varieties reduced (P < 0.05) LDL:HDL and TC:HDL ratios compared with the 1% dairy milk control. Consumption of the moderate-fat PS-enriched soymilk reduced (P < 0.05) cholesterol absorption by 27%, but did not alter cholesterol synthesis in comparison with 1% dairy milk.

Conclusion

We conclude that, compared to 1% dairy milk, consumption of low and moderate-fat PS-enriched soy beverages represents an effective dietary strategy to reduce circulating lipid concentrations in normal to hypercholesterolemic individuals by reducing intestinal cholesterol absorption.

Trial registration (clinicaltrials.gov)

NCT00923403 (Study 1), NCT00924391 (Study 2).