How Do Phytosterols Lower Cholesterol?


Phytosterols, also known as plant sterols, have received a lot of attention due to their heart healthy benefits. Commonly found in natural foods, such as nuts, fruit, and vegetables, phytosterols can also be found in supplemental form in your health store or pharmacy. Studies have found that daily consumption of anywhere between 1.6 and 3 grams of phytosterols could lower your LDL cholesterol by anywhere between 4 and 15%.

 However, HDL cholesterol and triglycerides do not appear to be greatly affected by the consumption of phytosterols. Although the manner in which LDL cholesterol is lowered by phytosterols is not completely known, there have been some studies that have examined how phytosterols may affect your LDL cholesterol levels.

LDL-Lowering Mechanism Is Unclear

Normally, cholesterol -- both from your food and liver -- is absorbed through the small intestine and circulates into the bloodstream.

Phytosterols, which have a similar structure to cholesterol molecules, are minimally absorbed from the small intestine. Therefore, phytosterols do not enter into the bloodstream and are instead excreted.  Some studies have found that phytosterols may be able to stop or slow the absorption of dietary cholesterol. These studies have identified certain molecules in the small intestine that are possibly modified by phytosterols, such as adenosine triphosphate cassette binding transporter A1 (ABCA1).

These molecules are responsible for increasing the excretion of cholesterol in the feces. Other studies suggest that phytosterols may affect the way that cholesterol is metabolized in the body. These studies have shown that phytosterols may help lower the amount of VLDL cholesterol, IDL cholesterol and LDL cholesterol made in the liver.

Unfortunately, these studies are conflicting and the mechanism by which phytosterols do this is not fully known.

Although more studies are needed to determine how phytosterols work in lowering your LDL cholesterol, studies have shown that including phytosterol-rich foods into your diet and reducing the amount of saturated fats that you consume may help in reducing your LDL levels. Although many healthy foods contain phytosterols, it may not be enough to fully note the cholesterol-lowering effect of this nutrient. For instance, although 2 grams of phytosterols daily is needed to see a slight reduction of LDL cholesterol, it is estimated that the average person only obtains about 150 to 350 mg of phytosterols daily. Phytosterol-containing supplements and foods that are fortified with phytosterols may also help in increasing phytosterol intake.


Clifton P. Lowering cholesterol – a review on the role of plant sterols. Aust Fam Physician 2009;38:218-221.

Malinowski JM, MM Gehret. Phytosterols for dyslipidemia. Am J Health Syst Pharm 2010; 67:1165-1173.

Calpe-Berdiel L, JC Escola-Gil, F Blanco-Vaca. New insights into the molecular actions of plant sterol and stanols in cholesterol metabolism: a review. Atherosclerosis 2009; 203:18-31

Continue Reading