Dietary plant sterols supplementation does not alter lipoprotein kinetics in men with the metabolic syndrome

Dietary plant sterols supplementation has been demonstrated in some studies to lower plasma total and LDL cholesterol in hypercholesterolemic subjects. The cholesterol lowering action of plant sterols remains to be investigated in subjects with the metabolic syndrome. In a randomized, crossover study of 2 x 4 week therapeutic periods with oral supplementation of plant sterols (2 g/day) or placebo, and two weeks placebo wash-out between therapeutic periods, we investigated the effects of dietary plant sterols on lipoprotein metabolism in nine men with the metabolic syndrome. Lipoprotein kinetics were measured using [D-3]-leucine, gas chromatography-mass spectrometry and compartmental modeling. In men with the metabolic syndrome, dietary plant sterols did not have a significant effect on plasma concentrations of total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, apolipoprotein (apo) B, apoA-I or apoA-II. There were no significant changes to VLDL-, IDL-, LDL-apoB or apoA-I fractional catabolic rates and production rates between therapeutic phases. Relative to placebo, plasma campesterol, a marker of cholesterol absorption was significantly increased (2.53 +/- 0.35 vs. 4.64 +/- 0.59 mu g/ml, p<0.05), but there was no change in plasma lathosterol, a marker of endogenous cholesterol synthesis. In conclusion, supplementation with plant sterols did not appreciably influence plasma lipid or lipoprotein metabolism in men with the metabolic syndrome. Future studies with larger sample size, stratification to low and high cholesterol absorbers and cholesterol balance studies are warranted.