Background: The relationship between plant sterol (PS) absorption and circulatory concentrations with cholesterol absorption and biosynthesis during PS consumption has yet to be clearly elucidated in humans. It is therefore essential to examine campesterol, β-sitosterol, and cholesterol absorption and cholesterol fractional synthesis rate (FSR) following PS consumption in individuals with high versus low basal circulatory PS concentrations.
Design: A randomized, crossover trial was conducted in 82 hypercholesterolemic men consuming spreads with or without 2 g/d of PS for two 4-week periods, each separated by a 4-week washout. Endpoint tracer enrichments after ingestion of (2)H-labeled campesterol or β-sitosterol and (13)C-labeled cholesterol were determined by isotope ratio mass spectrometry.
Results: For both phases of dietary intervention, the endpoint cholesterol absorption index was positively correlated with campesterol (r = 0.5864, p < 0.0001) and β-sitosterol (r = 0.4676, p < 0.0001) absorption indices; inversely, endpoint cholesterol FSR correlated negatively with the absorption indices of campesterol (r = -0.5004, p < 0.0009), β-sitosterol (r = -0.4154, p < 0.05), and cholesterol (r = -0.4056, p < 0.0001). PS intervention reduced absorption indices of campesterol, β-sitosterol, and cholesterol by 36.5% ± 2.7%, 39.3% ± 2.9%, and 34.3% ± 1.9%, respectively, but increased cholesterol FSR by 33.0% ± 3.3% relative to control. Endpoint circulatory PS levels (cholesterol adjusted) were positively associated with endpoint absorption indices of campesterol (r = 0.5586, p < 0.0001, for placebo; r = 0.6530, p < 0.0001, for PS intake) and cholesterol (r = 0.3683, p < 0.001 for placebo; r = 0.3469, p < 0.002, for PS intake) and were negatively associated with cholesterol FSR (r = -0.3551, p < 0.002, for placebo; r = -0.3643, p < 0.001, for PS intake). The cholesterol-lowering effect of PS was most pronounced among individuals falling within the 50th-75th percentiles of basal PS concentrations.
Conclusion: These data suggest that basal PS concentrations indicate not only sterol absorption efficiency but also the extent of PS-induced cholesterol reduction and thus might be clinically useful to predict the extent of cholesterol response to PS intervention within a given individual.