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 [D3]-
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 mug/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.