Objective: To study whether olive oil and rapeseed oil have different effects on cholesterol metabolism.
Design: Short-term experimental study, with controlled diets.
Setting: Outpatients at a metabolic-ward kitchen.
Subjects: A total of nine volunteers with conventional ileostomies.
Interventions: Two 3-day diet periods; controlled diet including 75 g of rapeseed oil or olive oil.
Main outcome measures: Cholesterol absorption, ileal excretion of cholesterol, and bile acids. Serum levels of cholesterol and bile acid metabolites. Differences between diets evaluated with Wilcoxon's signed rank sum test.
Results: Rapeseed oil diet contained 326 mg more plant sterols than the olive oil diet. Rapeseed oil tended to decrease cholesterol absorption by 11% (P = 0.050), and increased excretion of cholesterol, bile acids, and their sum as sterols by 9% (P = 0.021), 32% (P = 0.038), and 51% (P = 0.011) compared to olive oil. A serum marker for bile acid synthesis (7alpha-hydroxy-4-cholesten-3-one) increased by 28% (P = 0.038) within 10 h of consumption, and serum cholesterol levels decreased by 7% (P = 0.024), whereas a serum marker for cholesterol synthesis (lathosterol) as well as serum levels of plant sterols remained unchanged.
Conclusions: Rapeseed oil and olive oil have different effects on cholesterol metabolism. Rapeseed oil, tends to decrease cholesterol absorption, increases excretion of cholesterol and bile acids, increases serum marker of bile acid synthesis, and decreases serum levels of cholesterol compared to olive oil. This could in part be explained by different concentrations of natural plant sterols.
Sponsorship: Supported by the Göteborg Medical Society, the Swedish Medical Society, the Swedish Board for Agricultural Research (SJFR) grant 50.0444/98 and by University of Göteborg.