phytosterol

Phytosterol is a collective term for plant-derived sterols and stanols that are structurally similar to cholesterol and occur naturally in plant cell membranes. They are not essential nutrients but have a well established effect on lipid metabolism. The most abundant phytosterols in the diet are beta-sitosterol, campesterol, and stigmasterol, while stanols such as sitostanol and campestanol are saturated forms. Phytosterols are found in vegetable oils (especially sitosterol-rich oils), nuts, seeds, whole grains, and many fruits; they are also added to several fortified foods and dietary supplements.

In the human gut, phytosterols compete with cholesterol for incorporation into micelles, reducing the intestinal absorption of dietary cholesterol. This leads to lower low-density lipoprotein (LDL) cholesterol in many individuals, with typical reductions of about 5-15% when 1.5–3 grams of phytosterols or stanols are consumed daily as part of a cholesterol-lowering strategy. The magnitude of the effect depends on baseline cholesterol, overall diet, and the form of intake. Because phytosterols are not fully absorbed, high intake can modestly decrease absorption of fat-soluble vitamins and carotenoids; long-term high-dose use should consider monitoring.

Safety and regulation: phytosterols are generally considered safe when consumed in typical amounts from foods. A rare genetic condition called sitosterolemia causes marked elevation of plasma phytosterols and premature atherosclerosis; affected individuals should avoid high-phytosterol diets. In many jurisdictions, foods fortified with phytosterols/stanols may carry health claims about LDL-C reduction as part of a balanced diet.

Applications: used in functional foods such as fortified margarines, spreads, dairy alternatives, and cereals to support cholesterol management.