Since 2000, the US Food and Drug Administration (FDA) has permitted the manufacturers of Benecol®, a spread used in place of butter, to label the product as “heart-healthy.” Benecol® contains substances called stanol esters that have been shown to improve cholesterol profile. Stanol esters are manufactured from stanols, substances found in many plant sources. A very large body of evidence indicates that both stanols and stanol esters can reduce levels of LDL (“bad”) cholesterol, without affecting HDL (“good”) cholesterol levels. This leads to an improvement in total cholesterol and LDL/HDL ratio, and therefore reduced risk of cardiovascular disease.
Although stanols and stanol esters come from a natural source, to some people they do not entirely have the “feel” of a wholesome natural product. Why? Because they are often manufactured from wood pulp or tall oil (a byproduct of paper manufacturing). This has led to interest in related substances known as sterols as a substitute for stanols. Sterols are widely present in foods that we consume every day. A growing body of evidence now tells us that sterols and sterol esters are just as effective as stanols.
Sterols, stanols, and their esters all work in the same way. They are structurally similar to cholesterol, and because of this they displace cholesterol from the biochemical "packages" that deliver cholesterol through the intestines into the bloodstream. When cholesterol is thus detached, it cannot be absorbed, and is instead excreted. Via this process, sterols and stanols interfere with the absorption of cholesterol present in food, but much more importantly they remove the cholesterol from certain biochemicals manufactured in the liver and cycled through the digestive tract.
The effective dosage of stanols and stanol esters has been well-established at approximately 3-6 grams daily. However, the proper dose of sterol and sterol esters remains less well-defined. A study published in 2007 attempted to discover whether a relatively low dose of sterol esters would have a beneficial effect on cholesterol profile. In this double-blind study, sixteen people with high cholesterol were given either placebo or sterol esters at a dose of 1.3 grams per day. The results showed that use of sterol esters reduced LDL cholesterol as compared to placebo, and by the end of the study LDL/HDL ratio was 10% lower in the sterol ester group than in the placebo group.
Even though this was a small study, the results were statistically significant. Previous studies have found larger benefits when sterols or sterol esters were taken at 2.5-6 grams daily.
Supplements containing sterols or sterol esters are widely available. For more information, including dosage and safety issues, see the full sterol/stanol article .