Nutrition and metabolismPhytosterols and cholesterol metabolismOstlund, Richard E JrAuthor Information Division of Endocrinology, Diabetes and Lipid Research, Department of Internal Medicine, Washington University, St Louis, Missouri, USA Correspondence to Richard E. Ostlund, Jr, MD, Division of Endocrinology, Diabetes, and Lipid Research, Box 8127, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO 63110, USA Tel: +1 314 362 8286; fax: +1 314 747 4471; e-mail: [email protected] Current Opinion in Lipidology: February 2004 - Volume 15 - Issue 1 - p 37-41 Buy Abstract Purpose of review Phytosterols are plant sterols structurally similar to cholesterol that act in the intestine to lower cholesterol absorption. Because they have very low systemic absorption and are already present in healthy diets, increasing the intake of phytosterols may be a practical way to reduce coronary heart disease with minimum risk. Recent findings Phytosterols displace cholesterol from intestinal micelles, reducing the pool of absorbable cholesterol, but they are also rapidly taken up by enterocytes and increase expression of the adenosine triphosphate-binding cassette A1 sterol transporter. Phytosterol esters dissolved in food fat reduce LDL-cholesterol by 10% at a maximum effective dose of 2 g/day. However, this work probably understates the true effectiveness of phytosterols because it does not account for those naturally present in baseline diets. Single meal studies show that phytosterols in intact foods are bioactive at doses as low as 150 mg. The potential effectiveness of phytosterols has been improved in several ways. Individuals most likely to respond have been identified as having high cholesterol absorption and low cholesterol biosynthesis. Phytosterols can be emulsified with lecithin and delivered in non-fat or low-fat foods and beverages, and the amount of fat in fat-based preparations can be reduced substantially with the retention of bioactivity. Summary Phytosterols effectively reduce LDL-cholesterol when given as supplements, and the smaller amounts in natural foods also appear to be important. Future work will focus on the better delivery of phytosterols in natural foods and supplements and on further defining the mechanisms of action. © 2004 Lippincott Williams & Wilkins, Inc.