‘Oxysterols’: Their occurrence and biological effects

Abstract Products of cholesterol oxidation are discussed as a possible cause of arteriosclerotic lesions. These products are formed from cholesterol by the effects of heat, light and radiation. This paper gives a review about some of the most important cholesterol oxidation products and the current knowledge of their adverse biological effects. Oxidation products may be cytotoxic, atherogenic, mutagenic and carcinogenic and may inhibit cholesterol biosynthesis and membrane function. Little is known about the biological effects of other oxidized sterols like phytosterols. In foods, sterol oxidation products (‘oxysterols’) may be formed during processing, preparation and storage. They have been detected in many foods. The occurrence of ‘oxysterols’ in eggs, egg products, meat, fats and oils, fish, milk and milk products is summarized.