The invention relates to a substance which lowers LDL cholesterol levels in serum and which is fat soluble .beta.-sitostanol fatty acid ester, and to a method for preparing and using the same. The substance can be taken orally as a food additive, food substitute or supplement. A daily consumption of the .beta.-sitostanol ester in an amount between about 0.2 and about 20 g/day has been shown to reduce the absorption of biliary and endogenic cholesterol.