Stanol esters are a saturated subgroup of sterol esters. Plant stanol esters in Benecol products are fatty acid esters of plant sterols. The sterol part of the molecule is sitostanol or campestanol while the fatty acid residue originates from different vegetable oils. Plant stanol esters have the following physical properties:  These physical properties can be tailored by changing the fatty acid composition. In different technological applications of Benecol products, the fatty acid part is selected so that the melting properties, texture and other characteristics of the plant stanol ester closely resemble the properties of the fat it replaces. Under normal storage and food preparation conditions, plant stanol esters are very stable because they are more resistant to oxidation than the commonest vegetable oils. Using plant stanol esters in food applications instead of conventional fats does not decrease the shelf life of the end product. As is the case for all fats and oils, stanol esters should be protected from heat, air and light to prevent oxidation. If long-term storage is required, plant stanol esters are typically refrigerated in solid form. Furthermore, the usual antioxidants can be added to plant stanol ester products as they are to other oils or fats to minimise oxidation. Esterified plant stanols have been proven to reduce cholesterol in a number of randomised, placebo-controlled double-blind clinical trials. However absolutely no effect on clinical endpoints such as CVD or mortality was demonstrated. Plant stanol reduce both cholesterol and plant sterol levels in serum. This may be of importance since elevated plant sterol concentrations have been identified as an independent risk factor for coronary heart disease (CHD). Two ABC transporters (ABCG5 and ABCG8) play an important role in the regulating the intestinal absorption of plant sterols by resecreting previously absorbed plant sterols from the enterocytes back into the intestinal lumen. Mutations in these transporter proteins lead to a rare congenital disease called sitosterolaemia, which is characterised by:  It was recently shown that polymorphisms in the ABCG5 and ABCG8 genes contribute to modifying serum plant sterol levels in healthy, non-sitosterolaemic individuals. Furthermore, several epidemiological studies have shown that the risk of developing heart disease seems to be increased even at more "normal" plant sterol levels. Since statins were shown to increase serum plant sterol concentrations, patients should probably not be treated with statins alone but with a combination therapy focusing simultaneously on improving the serum lipoprotein profile and lowering serum plant sterol concentrations.