Phytosterols are plant steroids, which have a similar structure and function to cholesterol. Phytosterols are divided into two categories: sterols and stanols. The most common plant sterols include β-sitosterol, stigmasterol, campesterol and the like. The diet of early humans was rich in plant sterols (1 g/day). In comparison, the typical modern Western diet consumes much less plant sterols, only 150-400 mg per day.
Clinical studies have pointed out that the intake of plant sterols can reduce cholesterol in the body: total cholesterol can be reduced by 10%, and low-density lipoprotein cholesterol content can be reduced by 15%. More and more evidence shows that eating more plant foods rich in plant sterols can reduce the risk of cardiovascular disease. Beta-sitosterol is a type of plant sterol that has been used to treat hypercholesterolemia (a symptom of very high cholesterol in the blood).
How plant sterols work
Bile salts, lipids, and sterols formed in the small intestine will mix to form micelles; cholesterol in the diet must be mixed with this micelles and become a part of it to be absorbed by the small intestinal epithelial cells. Phytosterols will compete with cholesterol and be mixed with micelles first. In fact, plant sterols have more affinity than cholesterol and are easier to bind to micelles, thereby reducing the body's absorption of cholesterol. Cholesterol that cannot be absorbed by the body will be excreted through feces in a free form. In this way, plant sterols accelerate the excretion of cholesterol from the body.