This is a double-blind randomized study. The study population will consist of 30 consecutive patients who will undergo an elective carotid endarterectomy due to a tight asymptomatic stenosis. The patients will be randomized into two groups consuming either plant sterol (2g/day) or plant stanol (2g/day) spreads for two to six weeks, until the operation. Serum lipids, lipoproteins and sterols will be analyzed at the randomization, before the operation and one month after the operation. The carotid arteries will be examined for their composition of sterols.