Background: Plant sterols are natural dietary components with serum cholesterol-lowering properties. The lowering of serum cholesterol by plant sterols is believed to be the result of an inhibition of cholesterol absorption in the small bowel, although increased bile acid excretion has also been suggested. The difference in effect of saturated and unsaturated plant sterols on cholesterol absorption needs to be elucidated further.
Objective: The primary aim of this study was to measure small-bowel cholesterol absorption and sterol excretion in addition to hepatic cholesterol synthesis after intake of soy sterol esters and beta-sitostanol ester corresponding to 1.5 g plant sterols/d.
Design: Seven ileostomy subjects were studied during a control period and 2 intervention periods when either soy sterol esters or beta-sitostanol ester was added to a basal diet. Ileostomy bags were collected every other hour and frozen immediately for analysis of nutrients and sterols.
Results: Cholesterol absorption was 56% (43-65%) in the control period and decreased to 38% (32-46%) in the soy sterol ester period (P = 0.00) and to 39% (30-48%) in the beta-sitostanol ester period (P = 0.00).
Conclusion: Esterified soy sterols and beta-sitostanol inhibited cholesterol absorption equally, despite the different structures of the plant sterols.