ABSTRACT
Phytosterols make up the greatest proportion of the unsaponifiable matter of plant lipids, but constitute only a minor proportion of the unsaponifiable matter of animal tissues, where cholesterol predominates. Both cholesterol and plant sterols naturally occur in the nonesterified and esterified form, along with conjugates with glycosides. Each plant species contains a characteristic phytosterol composition, which usually does not include cholesterol (1). The major plant sterol is sitosterol, whereas campesterol, stigmasterol, ∆7-avenasterol, and brassicasterol are minor components. Depending on their structure and molecular weight, the phytosterols may be absorbed by the normal human intestine to a maximum of 5% of the absorption of free dietary cholesterol, but in patients with sitosterolemia the absorption of phytosterols may reach 30% of cholesterol absorption (2).
