What is it?
Beta-sitosterol is one of a group of organic compounds found in plants that, alone and in combination with similar plant sterols, reduces blood levels of cholesterol.1 2 3
Where is it found?
Beta-sitosterol is one of several plant sterols (cholesterol is the main animal sterol) found in almost all plants. High levels are found in rice bran, wheat germ, corn oil, and soybeans. Peanuts and its products, such as peanut oil, peanut butter, and peanut flour, are good sources of plant sterols, particularly beta-sitosterol.4
Why do athletes use it?*
Some athletes say that beta-sitosterol
- helps boost resistance to infection.
What do the advocates say?*
A combination of beta-sitosterol (BSS) and BSSG, a related compound, is known to enhance some parts of the immune system in animals and humans. While not proven to prevent infections in athletes, this combination has been shown to prevent the decline in immune function often experienced at the end of an ultramarathon.
How much is usually taken by athletes?
BSS, a natural sterol found in many plants, has been shown in a double-blind trial to improve immune function in marathon runners when combined with a related substance called B-sitosterol glucoside (BSSG).5 This implies that beta-sitosterol might reduce infections in athletes who engage in intensive exercise, though studies are still needed to prove this. The usual amount of this combination used in research is 20 mg of BSS and 200 mcg of BSSG three times per day.
Are there any side effects or interactions?
Ingesting plant sterols interferes with beta-carotene and vitamin E absorption, resulting in lower blood levels of these nutrients.6
*Athletes and fitness advocates may claim benefits for beta-sitosterol based on their personal or professional experience. These are individual opinions and testimonials that may or may not be supported by controlled clinical studies or published scientific articles on beta-sitosterol. For more complete and detailed information, including references and safety information, see Beta-Sitosterol as a nutritional supplement.
References
1. Lees AM, Mok HYI, Lee RS, et al. Plant sterols as cholesterol-lowering agents: clinical trials in patients with hypercholesterolemia and studies of sterol balance. Atherosclerosis 1977;28:325-38.
2. Pelletier X, Belbraouet S, Mirabel D, et al. A diet moderately enriched in phytosterols lowers plasma cholesterol concentrations in normocholesterolemic humans. Ann Nutr Metab 1995;39:291-5.
3. Jones PJ, Raeini-Sarjaz M, Ntanios FY, et al. Modulation of plasma lipid levels and cholesterol kinetics by phytosterol versus phytostanol esters. J Lipid Res 2000;41:697-705.
4. Awad AB, Chan KC, Downie AC, Fink CS. Peanuts as a source of ß-sitosterol, a sterol with anticancer properties. Nutr Cancer 2000;36:238–41.
5. Bouic PJD, Clark A, Lamprecht J, et al. The effect of B-sitosterol (BSS) and B-sitosterol glucoside (BSSG) mixture on selected immune parameters of marathon runners: Inhibition of post marathon immune suppression and inflammation. Int J Sports Med 1999;20:258–62.
6. Richelle M, Enslen M, Hager C, et al. Both free and esterified plant sterols reduce cholesterol absorption and the bioavailability of beta-carotene and alpha-tocopherol in normocholesterolemic humans. Am J Clin Nutr 2004;80:171–7.
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2006-09-07
