Phytosterols, which encompass plant sterols and stanols

Plant stanol ester

Stanol esters are a heterogeneous group of phytosterol esters with a saturated sterol ring structure known to reduce the level of low-density lipoprotein cholesterol in blood when ingested. The starting material is sterols from plants...

, are steroid compounds similar to cholesterol which occur in plants and vary only in carbon side chains and/or presence or absence of a double bond. Stanols are saturated sterols, having no double bonds in the sterol ring structure. More than 200 sterols and related compounds have been identified. Free phytosterols extracted from oils are insoluble in water, relatively insoluble in oil, and soluble in alcohols.