Cholesterol-like plant substances are present in ordinary, daily human diet

Phytosterols, commonly referred to as plant sterols, constitute a class of naturally occurring steroid compounds characterized by a cyclic alcohol structure. Their defining physiological attribute is the competitive inhibition of intestinal cholesterol absorption, thereby effectively lowering plasma cholesterol concentrations. The most prominent members of this group include β-sitosterol (the most ubiquitous in nature), campesterol (abundant in corn oil), stigmasterol (prevalent in legumes), and brassicasterol (primarily found in canola oil). From a biological perspective, these sterols serve a membrane-stabilizing function in plant cells, analogous to the role of cholesterol in animal organisms. A notable exception is ergosterol—a precursor to vitamin D2—synthesized by *Chlorella* algae and certain fungal species.

Phytostanols, though frequently derived from phytosterols through synthetic processes, occur naturally across a broad spectrum of dietary sources, including fruits, cereals, nuts, and various plant-based oils. They constitute a chemically diverse class of bioactive compounds whose clinical significance stems from their well-documented capacity to reduce circulating low-density lipoprotein (LDL) cholesterol—commonly referred to as "bad cholesterol"—in blood plasma. Their mode of action involves competitive inhibition of dietary cholesterol absorption within the small intestine, concurrently facilitating its accelerated excretion via the biliary pathway. From a structural perspective, phytostanols represent saturated analogues of phytosterols, exhibiting notable conformational similarities to endogenous cholesterol molecules. Within the food industry, phytostanol esters are widely incorporated as functional ingredients in margarines and other fat-based products designed to improve the lipid profile of consumers.

The highest concentrations of phytosterols are observed in cold-pressed vegetable oils, including rapeseed oil, sesame oil, corn germ oil, soybean oil, and rice oil. Additionally, substantial quantities of these bioactive compounds are present in various nut varieties, leguminous seeds, and cereal sprouts—particularly those derived from wheat and maize. Due to their well-documented health benefits, phytosterols and plant stanols are widely incorporated as functional ingredients in foods designed to support cardiovascular disease prevention. Regular consumption of as little as 2 grams of plant stanols per day has been clinically demonstrated in multiple meta-analyses to reduce low-density lipoprotein (LDL) cholesterol levels—commonly referred to as "bad cholesterol"—by 10 to 20 percent. While natural plant stanols occur in trace amounts in fruits, whole-grain products, nuts, and certain oils, their concentrations are insufficient to produce a meaningful cholesterol-lowering effect. Significantly higher doses of these bioactive compounds are obtained through the consumption of fortified products, such as functional margarines, yogurts, or plant-based beverages. The mechanism of action for phytosterols and stanols involves competitive inhibition of cholesterol absorption in the small intestine, thereby reducing its bioavailability. Current dietary guidelines emphasize the role of these compounds in preventing atherosclerosis and other metabolic disorders, particularly in individuals with lipid metabolism dysfunctions. Their widespread, albeit low, presence in staple foods means that small amounts are consumed daily; however, achieving therapeutic effects typically requires supplementation or the intake of enriched foods.