sitostanol

Sitostanol is a plant-derived stanol, a saturated derivative of the plant sterol beta-sitosterol. It is used as a functional ingredient in foods and dietary supplements designed to lower circulating cholesterol, particularly low-density lipoprotein (LDL) cholesterol.

In foods, sitostanol is typically added as sitostanol esters to improve solubility in fats. Commonly fortified products include margarines, spreads, and certain dairy or bakery items. Because sitostanol is not significantly absorbed, its cholesterol-lowering action is local to the intestinal tract.

Mechanism and effects: Sitostanol competes with cholesterol for incorporation into mixed micelles in the small intestine, reducing the intestinal absorption of both dietary and biliary cholesterol. Over time, this decreases the amount of cholesterol delivered to the liver and lowers serum LDL-C. Typical LDL reduction with adequate intake of sitostanol-containing products is in the range of roughly 7–12%, depending on dose and background diet.

Safety and regulation: Sitostanol used in approved amounts in fortified foods is generally considered safe for the general population. Adverse effects are uncommon but may include mild gastrointestinal symptoms. High intakes could modestly reduce absorption of fat-soluble vitamins. Sitostanol is contraindicated in individuals with sitosterolemia, a rare genetic disorder. Regulatory labeling in many jurisdictions requires clear specification of sitostanol-containing products and dosage information.

Availability: In addition to fortified foods, sitostanol is available in supplement form, though consumers typically obtain the LDL-lowering benefit through daily consumption of marketed cholesterol-lowering products rather than standalone supplements.