Comparison of Effects of Dietary Unesterified and Esterified Plant Sterols on Cholesterol Absorption in Rats

Effects of dietary unesterified plant sterols and plant sterol oleates and stearates on absorption and metabolism of cholesterol were compared in rats fed a cholesterol-supplemented diet. Fecal excretion of neutral steroids (cholesterol plus coprostanol) in rats fed unesterified plant sterols or plant sterol oleates was significantly higher than in those fed the control diet or plant sterol stearates. Deposition of cholesterol in the liver was significantly lower in rats fed unesterified plant sterols or plant sterol oleates than in those fed the control diet or plant sterol stearates. No significant difference was observed in fecal excretion of cholesterol plus coprostanol and hepatic cholesterol concentration between unesterified plant sterols and plant sterol oleates. Unesterified plant sterols were significantly more effective to reduce lymphatic recovery of radiolabeled cholesterol given to the stomach than plant sterol oleates. Although our observations suggest a possibility that unesterified plant sterols are potentially more effective to inhibit cholesterol absorption than plant sterol oleates in rats, difference in the activity is substantially small between these two forms of plant sterols.