Plant sterols in our diet

Phytosterols are natural constituents of plants and they are structurally related to cholesterol, whereas phytostanols are the saturated forms of plant sterols. A typical western-type diet contains daily about 200–400 mg plant sterols, and about 50 mg of plant stanols. Plant sterols and stanols are known as cholesterol lowering agents, when they are consumed in high doses. Clinical trials have consistently shown that intake of 2–3 g/day of plant sterols is associated with significant lowering (4–15%) of LDL cholesterol. Total cholesterol is also reduced to similar extent, and recent studies have indicated beneficial effect on plasma triglyceride levels. In the inherited disease sitosterolemia, in which decrease excretion and elevated circulating, as well as, tissue levels of phytosterols are observed, atherosclerosis and cardiovascular events are the main causes of premature death. This pathological entity raised questions about the relation of increased consumption of phytosterols and cardiovascular risk despite the low levels of cholesterol. There are some epidemiological studies and clinical trials that confirm this hypothesis, while others do not. The guidelines from scientific societies are controversial. Some guidelines recommend the use of plant sterols as therapeutic agents for hypercholesterolemia, while others are cautious. Prospective clinical studies are needed to clarify the role of plant sterols to atherosclerosis and cardiovascular disease.