Stanols and sterols as dietary supplements
Stanols and sterols are natural substances derived from plants that are commonly used as dietary supplements to help lower cholesterol levels. They were first noted for their cholesterol-lowering effects in the 1950s, and subsequent research has demonstrated their potential benefits in managing cholesterol profiles, particularly for those with normal to moderately elevated cholesterol levels. Stanols are often modified into esters and can be found in various food products like margarine, salad dressings, and fortified foods, as well as dietary supplements.
These compounds work by structurally resembling cholesterol, allowing them to displace cholesterol from absorption in the intestines, which leads to increased excretion of cholesterol from the body. Clinical studies indicate that consuming stanol or sterol products can reduce total and LDL (bad) cholesterol by approximately 10-15%. However, they do not significantly affect HDL (good) cholesterol or triglycerides. Typical dosages for effectiveness range from 2.7 to 5.1 grams per day, and results may take several weeks to manifest.
While considered generally safe, some mild gastrointestinal side effects have been noted in rare cases. Importantly, these substances are not meant to replace medications for cholesterol management but can be beneficial alongside standard treatments, including statins. Further research is ongoing to better understand the full scope of their effects and potential benefits, particularly in specific populations such as individuals with type 2 diabetes.
Stanols and sterols as dietary supplements
- PRINCIPAL PROPOSED USE: Lowering cholesterol
DEFINITION: Natural substances promoted as dietary supplements for specific health benefits
Overview
Stanols are substances that occur naturally in various plants. Their cholesterol-lowering effects were first observed in animals in the 1950s. Since then, a substantial amount of research has suggested that plant stanolsusually modified into stanol esterscan help to lower cholesterol in persons with normal or mildly to moderately elevated levels. Stanols are available in margarine spreads, salad dressings, and dietary supplement tablets. Related substances called sterols or phytosterols, such as beta-sitosterol, and sterol esters appear to lower cholesterol in much the same manner as stanols.
Sources
Sterols are found in most plant foods and occur naturally in wood pulp, tall oil, and soybean oil. Stanols can also be manufactured from the sterols found in many foods, including nuts, seeds, legumes, whole grains, vegetables, and fruits. Some foods are fortified to contain these substances, such as yogurt, cocoa butter oil, milk, and fat spreads, and usually provide between .75 and two grams (g). Stanol and sterol esters are manufactured by processing stanols or sterols with fatty acids from vegetable oils. Stanol-sterols and their esters are added to margarine spreads and salad dressings and are also available as dietary supplement tablets.
Therapeutic Dosages
Typical dosages of stanol-sterols and their esters to improve cholesterol profile range from 2.7 to 5.1 g per day. One study suggests that using stanol products once a day may be as effective as dividing up the intake throughout the day. It may take up to three months to show a substantial decrease in total cholesterol values.
Therapeutic Uses
Strong evidence suggests that stanol-sterols and their ester forms can significantly improve cholesterol profile. Some studies indicate they may support the immune system. There are no other known medicinal uses of stanols or stanol esters. Phytosterols do offer additional potential benefits.
Scientific Evidence
Because they are structurally similar to cholesterol, stanols and sterols can displace cholesterol from the “packages” that deliver cholesterol for absorption from the intestines to the bloodstream. This displaced cholesterol is then excreted from the body. This action not only interferes with the absorption of cholesterol from food. It also has the additional, and probably more important, effect of removing cholesterol from substances made in the liver that are recycled through the digestive tract.
Numerous double-blind, placebo-controlled studies, ranging in length from thirty days to twelve months and involving more than one thousand people, have found that sterol-stanols and their esters are effective for improving cholesterol profile. The combined results suggest that these substances can reduce total cholesterol and LDL, or bad, cholesterol by about 10-15 percent. They do not, however, have much of an effect on HDL, or good cholesterol, or triglycerides.
For example, in a double-blind, placebo-controlled study, 153 people with mildly elevated cholesterol were given sitostanol esters in margarineat a dose of 1.8 or 2.6 g of sitostanol per dayor margarine without sitostanol ester for one year. The results in the treated group receiving 2.6 g per day showed improvements in total cholesterol by 10.2 percent and LDL cholesterol by 14.1 percent, significantly better than the results in the control group. Neither triglycerides nor HDL cholesterol levels were affected. However, further studies have shown positive impacts on cholesterol levels in individuals with specific health conditions. Further large-scale research is needed to understand the relationship between these chemicals and the body’s lipid levels.
Fish oil has also been shown to favorably affect fats in the blood, particularly triglycerides. A study investigating the possible benefit of combining sterols with fish oil found that they significantly lowered total cholesterol, LDL cholesterol, and triglycerides and also raised HDL cholesterol in persons with undesirable cholesterol profiles.
Even people already taking standard medications to improve cholesterol profilespecifically drugs in the statin familyappear to benefit when they also use stanols-sterols. According to one study, people on statins who start taking sterol ester margarine will also improve to the same extent as if those persons doubled the statin dose. Stanols and sterols also appear safe and effective for improving cholesterol profile in people with type 2 diabetes.
Safety Issues
Sterols are presumed safe because they occur in many foods. Stanols are also considered safe, but for a different reason: They are not absorbed. No adverse effects have been reported in any of the studies on lowering cholesterol, except for one study that reported mild gastrointestinal complaints in a few preschool children. In addition, no toxic signs were observed in rats given stanol esters for thirteen weeks at levels comparable to or exceeding those recommended for lowering cholesterol.
Although concerns have been expressed that stanol esters might impair absorption of the fat-soluble vitamins A, D, and E, this does not seem to occur at the dosages required to lower cholesterol. Stanol esters might interfere with the absorption of alpha-carotene and beta-carotene, although some studies have found no such effect.
Stanols and sterols supplements are not a substitute for medications. Most data indicates that these chemicals are most impactful when consumed in foods rather than supplements.
Bibliography
Allen, R. R., et al. “Daily Consumption of a Dark Chocolate Containing Flavanols and Added Sterol Esters Affects Cardiovascular Risk Factors in a Normotensive Population with Elevated Cholesterol.” Journal of Nutrition, vol. 138, 2008, pp. 725-31.
Barkas, Fotios, et al. “Plant Sterols and Plant Stanols in Cholesterol Management and Cardiovascular Prevention.” Nutrients, vol. 15, no. 13, June 2023, p. 2845. doi:10.3390/nu15132845.
Castro Cabezas, M., et al. “Effects of a Stanol-Enriched Diet on Plasma Cholesterol and Triglycerides in Patients Treated with Statins.” Journal of the American Dietetic Association, vol. 106, 2006, pp. 1564-69.
Jones, Peter J. H., et al. “Progress and Perspectives in Plant Sterol and Plant Stanol Research.” Nutrition Reviews, vol. 76, no. 10, 2018, pp. 725-46. doi:10.1093/nutrit/nuy032.
"Phytosterols." Cleveland Clinic, 30 July 2022, my.clevelandclinic.org/health/articles/17368-phytosterols-sterols--stanols. Accessed 1 Oct. 2024.
Plana, N., et al. “Plant Sterol-Enriched Fermented Milk Enhances the Attainment of LDL-Cholesterol Goal in Hypercholesterolemic Subjects.” European Journal of Nutrition, vol. 47, 2008, pp. 32-39.
"Stanols and Sterols: Food Fact Sheet." British Dietetic Association, www.bda.uk.com/resource/food-facts-plant-stanols-and-sterols.html. Accessed 1 Oct. 2024.
Trautwein, Elke A., et al. “LDL-Cholesterol Lowering of Plant Sterols and Stanols-Which Factors Influence Their Efficacy?” Nutrients, vol. 10, no. 9, Sept. 2018, p. 1262. doi:10.3390/nu10091262.