What Is It?
Health Benefits
Dosage Information
Guidelines for Use
General Interaction
Possible Side Effects

Evidence Based Rating Scale
What Is It?

Plant sterols and plant stanols are collectively known as phytosterols. Plant sterols are plant compounds with chemical structures similar to that of cholesterol. Especially high sterol levels are found in rice bran, wheat germ, corn oils, and soybeans. In a more concentrated form, these substances are called plant stanols. However, unlike cholesterol derived from animal sources--which absorbs easily and raises the body's own cholesterol levels--phytosterols are present only at very low levels in the body because they are difficult to absorb.

Interestingly, phytosterols so closely resemble cholesterol that they can actually block food-based cholesterol from being absorbed into the bloodstream. This results in both the phytosterols and dietary cholesterol end up excreted in waste matter.

Recently food manufacturers have begun to incorporate plant sterols and stanols into such "functional foods" as vegetable oil spreads (Benecol or Take Control, for example). Nutritional supplement manufacturers also offer phytosterols in tablet form for those individuals who don't want the extra calories of cholesterol-lowering margarine.

Concentrated extracts of another phytosterol called beta sistosterol have been tested for lessening such discomforts of benign prostatic hyperplasia (BPH) and frequent and painful urination (see the library entry on beta-sistosterol for more detailed information).

Health Benefits

Because of their ability to block dietary cholesterol absorption, phytosterols can help lower your cholesterol levels. In the last few years, clinical research has also discovered other effects, including reducing symptoms of an enlarged prostate, improving the control of blood sugar among people with diabetes, and reducing inflammation among patients with autoimmune diseases such as rheumatoid arthritis and lupus.

Because much of this research is still in a preliminary phase, nutritionally oriented physicians are currently recommending obtaining phytosterols by eating whole foods. Generally, phytosterol supplements are usually only prescribed for those experiencing prostate disorders and patients needing to lower their cholesterol.

Specifically, phytosterols may help to:

·  Prevent heart disease. By lowering total and LDL cholesterol levels, plant sterols and stanols may reduce your risk of heart disease. Studies have shown that daily ingestion of phytosterols can lower these cholesterol measurements by an average of 10% to 14%. Because of these strong findings, the National Cholesterol Education Panel issued a new recommendation in 2001 that plant stanols and sterols be added to cholesterol-lowering regimens, along with the more traditional cholesterol-fighting tools, such as regular exercise, weight loss, and a low-fat diet (1). Phytosterols do not appear to lower triglycerides, another blood lipid that is harmful in excess, or to raise levels of HDL, the "good" cholesterol. Recent study results find that supplementing your diet with phytosterols may be nearly as effective as lipid lowering statin drugs (2). In fact the same trial demonstrated that nine out of thirty-four participants were able to achieve lower LDL levels by implementing a diet high in plant sterols, than by taking statin drugs. The mechanism behind the improvement in LDL levels is not fully understood, but study results now suggest that phytosterols may lower the LDL particle size (3). There is debate about whether the sterol or stanol particles are more effective at lowering cholesterol (4). What w do know however, is that smaller LDL particles area more easily excreted by the body resulting in lower risk of adverse cardiac events and disease.


·  Work together with other agents to combat heart disease. Phytosterols do not appear to inhibit the action of other heart friendly supplements such as hawthorn, or fish oils. However, more research is necessary to examine the benefits of combining supplements and conventional drugs to treat heart disease (5). During menopause women may want to investigate the possible heart healthy effects of soy based plant proteins as this can do double duty, working to reduce the effects of menopause and heart disease (6).



·  Ease enlarged prostate. For the last 20 years, an herbal preparation containing phytosterols has been available in Germany for treatment of benign prostate hypertrophy (BPH) (7). More recently, a meta-analysis including 519 men with BPH, given the phytosterol beta-sitosterol, showed an increase in their urinary flow rate and a decrease in pain and burning (8).


·  Calm inflammation in rheumatoid arthritis (RA). Most traditional treatments for RA involve drugs that suppress the body's immune response, which can often cause troubling side effects. A mixture of the phytosterols beta-sitosterol and beta-sistosterolin has shown promise in helping to decrease inflammation and calm the overactive immune response that characterizes RA and other autoimmune diseases (9). More research is needed, however.


·  Control blood sugar in diabetes. Some phytosterols stimulate insulin secretion and may contribute to better blood sugar control, a problem in people with diabetes. Animal studies have suggested that beta-sitosterol and beta-sistosterolin might be beneficial for people with diabetic and pre-diabetic conditions. More research is necessary before these findings are recommended to people with diabetes.


·  Protect against and inhibit the growth of cancer. Medical researchers estimate that dietary factors contribute nearly 1/3 to our total risk of developing cancer over course of our lives. Recent studies suggest that two phytosterols, taraxasterol and beta-sitosterol, may inhibit breast and colon cancer (10, 11). More research is needed to determine how these plant sterols inhibit tumor proliferation and metastasis. However, since there have been no observed side effects from increased phytosterol ingestion, it may be a good idea to ensure increased levels of these plant proteins in your diet to prevent cancer before it develops.

Dosage Information

Special tips:

--The cholesterol-controlling margarines such as Benecol and Take Control suggest a dose of 2 tablespoons daily to help lower total and LDL cholesterol levels.

For lowering cholesterol: Take 200-250 mg three times a day, with meals.

For enlarged prostate (BPH): Take 125-250 mg a day, on an empty stomach.

Guidelines for Use

·  Because phytosterols help block dietary cholesterol adsorption, they should be taken with meals.

·  Beta-sitosterol, when used for prostate enlargement, is generally taken on an empty stomach to enhance its absorption into the bloodstream.

·  Some research has shown that phytosterols can slightly lower concentrations of fat-soluble vitamins such as beta-carotene, but other studies show no such effect. Although carotene levels normally vary with the seasons, it may be a reasonable precaution to increase your intake of beta-carotene (or carotene-containing foods such as carrots, yellow squash, and sweet potatoes) while taking phytosterol supplements.

·  If you are taking phytosterols in the margarine form, simply replace your usual spread. You may need to eat somewhat larger amounts than you are accustomed to in order to achieve an effective dose.

·  Today nutrition minded food companies are adding phytosterols to many kinds of food. Look for bakery goods, or cereals high in phytosterols if you do not want to try them in pill form.

Be sure to check out our Dosage Recommendations Chart which lists therapeutic dosages for specific ailments at a glance.

General Interaction

·  There are no known drug or nutrient interactions associated with phytosterols in typical doses. There may be some reduction in the body's levels of carotenoids, but this finding is under debate.

Possible Side Effects

·  At typical doses, there are no known side effects or adverse reactions. However, in one study in which participants took three to four times the suggested dose, some gastrointestinal upset occurred.


·  There are no known cautions associated with plant sterols.




  1. Varady KA, Ebine N, Vanstone CA, Parsons WE, Jones PJ. Plant sterols and endurance training combine to favorably alter plasma lipid profiles in previously sedentary hypercholesterolemic adults after 8 wk. Am J Clin Nutr. 2004 Nov;80(5):1159-66.
  2. Jenkins DJ, Kendall CW, Marchie A, Faulkner DA, Wong JM, de Souza R, Emam A, Parker TL, Vidgen E, Trautwein EA, Lapsley KG, Josse RG, Leiter LA, Singer W,Connelly PW. Direct comparison of a dietary portfolio of cholesterol-lowering foods with a statin in hypercholesterolemic participants. Am J Clin Nutr. 2005 Feb;81(2):380-7.
  3. Lamarche B, Desroches S, Jenkins DJ, Kendall CW, Marchie A, Faulkner D, Vidgen E, Lapsley KG, Trautwein EA, Parker TL, Josse RG, Leiter LA, Connelly PW. Combined effects of a dietary portfolio of plant sterols, vegetable protein, viscous fibre and almonds on LDL particle size. Br J Nutr. 2004 Oct;92(4):657-63.
  4. O'Neill FH, Brynes A, Mandeno R, Rendell N, Taylor G, Seed M, Thompson GR. Comparison of the effects of dietary plant sterol and stanol esters on lipid metabolism. Nutr Metab Cardiovasc Dis. 2004 Jun;14(3):133-42.
  5. Normen L, Shaw CA, Fink CS, Awad AB. Combination of phytosterols and omega-3 fatty acids: a potential strategy to promote cardiovascular health. Curr Med Chem Cardiovasc Hematol Agents. 2004 Jan;2(1):1-12.
  6. Cicero AF, Minardi M, Mirembe S, Pedro E, Gaddi A. Effects of a new low dose soy protein/beta-sitosterol association on plasma lipid levels and oxidation. Eur J Nutr. 2004 Oct;43(5):319-22. Epub 2004 Jan 26.
  7. Madersbacher S, Schatzl G, Brossner C, Dreikorn K. Phytotherapy for BPS Welche Praparate konnen heute noch verschrieben werden? Urologe A. 2005 Feb 23;[Epub ahead of print]
  8. Wilt T, Ishani A, MacDonald R, Stark G, Mulrow C, Lau J. Beta-sitosterols for benign prostatic hyperplasia. Cochrane Database Syst Rev. 2000;(2):CD001043.
  9. Bouic PJ, Lamprecht JH. Plant sterols and sterolins: a review of their immune-modulating properties. Altern Med Rev. 1999 Jun;4(3):170-7.
  10. Ovesna Z, Vachalkova A, Horvathova K. Taraxasterol and beta-sitosterol: new naturally compounds with chemoprotective/chemopreventive effects. Neoplasma. 2004;51(6):407-14.
  11. Hlavaty T, Lukac L, Duris I. Is there any role for prevention strategies for colorectal cancer other than population-based screening? Bratisl Lek Listy. 2004;105(5-6):215-24.

Evidence Based Rating Scale 


The Evidence Based Rating Scale is a tool that helps consumers translate the findings of medical research studies with what our clinical advisors have found to be efficacious in their personal practice. This tool is meant to simplify which supplements and therapies demonstrate promise in the treatment of certain conditions. This scale does not take into account any possible interactions with any medication/ condition/ or therapy which you may be currently undertaking. It is therefore advisable to ask your doctor before starting any new treatment regimen.


















Date Published: 09/10/2005

Previous  |  Next
> Printer-friendly Version Return to Top

© 2000- 2019 ., LLC. 21251 Ridgetop Circle, Suite 150, Sterling, VA 20166. All rights reserved. Reproduction in whole or in part without permission is prohibited. Privacy Policy

Disclaimer: All material provided in the WholeHealthMD website is provided for educational purposes only. Consult your physician regarding the applicability of any information provided in the WholeHealthMD website to your symptoms or medical condition.