Absorbability of plant sterols in the rhesus monkeys

High- and low-responding rhesus monkeys were fed a semisynthetic high or low cholesterol diet with 2% plant sterols for 6 weeks to determine the absorbability of the plant sterols. No plant sterols were detected in the plasma of either high- or low-responding animals fed either high or low cholesterol diet containing low levels of plant sterols. After addition of 2% plant sterols to either of the diets, only campesterol was found in the plasma of all animals. The final plasma campesterol concentrations in the high-responders on high and low cholesterol diets containing high levels of plant sterols were 0.91 ± 0.14 (SE) and 1.16 ± 0.27 mg/dl, respectively. Similar values in the low-responders were 0.51 ± 0.06 and 0.24 ± 0.16 mg/dl, respectively. Sitosterol was occasionally detected in trace amounts in some animals of both groups on either high or low cholesterol diet. Stigmasterol was not detected in the plasma of any animals. We conclude, based on the plasma sterol levels, that rhesus monkeys absorb campesterol and probably do not absorb sitosterol or stigmasterol in any significant amount. The study also shows that the high-responders absorb higher amounts of campesterol than the low-responders; a finding similar in respect to cholesterol absorption in the high-responders.