In a recent post on the Science-Based Medicine blog, Dr. Harriet Hall reviewed The Mayo Clinic Book of Home Remedies. For elevated cholesterol, the book recommends trying “natural products,” including plant sterols. Plant sterols (aka phytosterols) are sold as supplements or in functional foods, such as certain margarines. It is true that plant sterol supplements will usually lower LDL (“bad”) cholesterol by a small amount, in the range of 5-15%. Unfortunately, there is no good evidence that plant sterols lower the risk of heart disease. In fact, it is possible that plant sterols actually promote heart disease.

1. There is a rare genetic disorder called sitosterolemia, characterized by very high serum plant sterols, in which patients develop premature heart disease. It is similar to homozygous familial hypercholesterolemia, except with very high plant sterols instead of very high LDL. The unfortunate victims develop xanthomas containing plant sterols and arteries clogged by plant sterols.

2. Plant sterol supplements have been shown to increase serum plant sterols in healthy people.

3. The safety of these elevated levels of plant sterols has not been established.

4. No clinical trials have been done to test whether plant sterol supplements reduce the risk of heart attacks and, so far as I know, no such trials are planned.

5. There are studies that have found plant sterols in atherosclerotic plaque (e.g., from people who have had endarterectomies) and in aortic valves of patients with aortic stenosis.

6. There are animal studies showing harm from plant sterol supplementation.

For the above reasons, plant sterol supplements cannot be recommended at the present time.

References:

Weingartner, et al. Vascular effects of diet supplementation with plant sterols. Journal of the American College of Cardiology, 2008;51:1553-1561, doi:10.1016/j.jacc.2007.09.074

Teupser, et al. Genetic Regulation of Serum Phytosterol Levels and Risk of Coronary Artery Disease. Circulation: Cardiovascular Genetics. 2010;3:331-339, doi:10.1161/CIRCGENETICS.109.907873

O. Weingartner, M. Bohm, and U. Laufs
Controversial role of plant sterol esters in the management of hypercholesterolaemia
European Heart Journal, February 2, 2009; 30(4): 404–409.