Beta-Sitosterol Plant Sterols

Phytosterols are natural components of many vegetables and grains. Preliminary scientific evidence suggests that plant phytosterols may help to maintain cholesterol levels already within the normal range when consumed as part of a low cholesterol dietary program. The three main phytosterols in our phytosterol complex are beta-sitosterol, campesterol, and stigmasterol. They are natural, safe and derived entirely from plant sources.

Beta sitosterol research studies
Efficacy and safety of beta sitosterol in the management of blood cholesterol levels.
Cardiovasc Drug Rev. 2005 Spring;23(1):57-70. Fernandez ML, Vega-Lopez S.
University of Connecticut, Department of Nutritional Sciences, Storrs, CT
Elevated levels of plasma LDL cholesterol (LDL-C) represent a major risk factor for cardiovascular disease. Treatments aimed at reducing levels of circulating LDL are regarded, therefore, as cardioprotective. The cholesterol lowering properties of plant sterols have been known for some time and many clinical studies have confirmed the efficacy of beta sitosterol in lowering plasma LDL-C concentrations. Animal studies have also shown reductions in LDL by beta sitosterol. The use of animal models has been useful in facilitating the elucidation of specific mechanisms by which beta sitosterol exerts its hypocholesterolemic action. It is well known that plant sterols compete with cholesterol for space within bile salt micelles in the intestinal lumen thereby reducing cholesterol absorption. The understanding of the function of plant sterols in impeding cholesterol absorption has been clarified with the discovery of the adenosine binding cassette transporters, ABCG5/8, involved in the regulation of sterol absorption and secretion into the enterocyte and hepatocyte. Compared to cholesterol and other sterols, beta sitosterol is preferentially pumped out to the intestinal lumen by the ABCG5/8 transporters. This selective binding of beta sitosterol to the transporters ultimately results in significant lowering of plasma cholesterol. However, some findings support the hypothesis that plant sterols might be an additional risk factor for coronary heart disease. From the review of these studies, it is apparent that beta sitosterol is a useful dietary supplement for the lowering of plasma cholesterol. Nevertheless, beta sitosterol should be used with caution in certain individuals who have a higher absorption rate of beta sitosterol.

Randomized trial of a combination of natural products (cernitin, saw palmetto, Beta sitosterol, vitamin E) on symptoms of benign prostatic hyperplasia.
Preuss HG. Int Urol Nephrol 2001;33(2):217-25. Georgetown University Medical Center, Washington, DC
Because benign prostatic hyperplasia (BPH) is relatively common, it is important to discover safe and effective means to treat this often debilitating perturbation. Accordingly, we examined the effectiveness of a combination of natural products (cernitin, saw palmetto, beta sitosterol, vitamin E) in treating symptoms of BPH. We undertook a randomized, placebo-controlled, double-blind study. Patients received either placebo or the combined natural products for 3 months. Nocturia showed a markedly significant decrease in severity in patients receiving cernitin, saw palmetto and beta sitosterol compared to those taking placebo. Daytime frequency was also lessened significantly. PSA measurements, maximal and average urinary flow rates, and residual volumes showed no statistically significant differences. When taken for 3 months, a combination of natural products (cernitin, saw palmetto, Beta sitosterol, vitamin E) compared to placebo can significantly lessen nocturia and frequency and diminish overall symptomatology of BPH as indicated by an improvement in the total AUA Symptom Index score. The combination of natural products caused no significant adverse side effects.

Beta Sitosterol, beta Sitosterol Glucoside, and a Mixture of beta Sitosterol and beta Sitosterol Glucoside Modulate the Growth of Estrogen-Responsive Breast Cancer Cells In Vitro and in Ovariectomized Athymic Mice.
University of Illinois at Urbana-Champaign, Urbana, IL
J Nutr. 2004 May;134(5):1145-51.
We hypothesized that the phytosterols beta sitosterol, beta sitosterol glucoside, and Moducare could modulate the growth of estrogen-dependent human breast cancer cells in vitro and in vivo. The effects of dietary beta sitosterol, beta sitosterol glucoside, and MC on the growth of MCF-7 cells implanted in ovariectomized athymic mice were evaluated. Estrogenic effects of the phytosterols were evaluated in the NC, beta sitosterol, beta sitosterol glucoside, and MC treatment groups, and anti-estrogenic effects were evaluated in the 17 beta estradiol (E(2)), E(2) + BSS, E(2) + beta sitosterol glucoside, and E(2) + MC treatment groups. Mice were treated with dietary beta-sitosterol, beta-sitosterol glucoside, or MC for 11 wk. Dietary beta sitosterol, beta sitosterol glucoside, and MC did not stimulate MCF-7 tumor growth. However, dietary beta sitosterol, beta sitosterol glucoside, and MC reduced E(2)-induced MCF-7 tumor growth by 38%, 31%), and 42%, respectively. The dietary phytosterols lowered serum E(2) levels compared to that of the E(2) treatment group. In summary, beta sitosterol and MC stimulated MCF-7 cell growth in vitro. Although beta sitosterol glucoside comprises only 1% of MC, beta sitosterol glucoside made MC less estrogenic than beta sitosterol alone in vitro. However, dietary beta sitosterol and MC protected against E(2)-stimulated MCF-7 tumor growth and lowered circulating E(2) levels.

A plant food-based diet modifies the serum beta-sitosterol concentration in hyperandrogenic postmenopausal women.
University at Buffalo, Buffalo, NY
J Nutr. 2003 Dec;133(12):4252-5.
Plant sterols or phytosterols are common components of plant foods, especially plant oils, seeds and nuts, cereals and legumes. The most common phytosterols are campesterol, beta-sitosterol and stigmasterol. Phytosterols have anti-carcinogenic properties. Previous studies have suggested that populations with low breast cancer incidence often consume diets high in phytosterols. The present study evaluated whether consumption of a plant food-based diet, low in animal fat, may increase serum phytosterol levels in postmenopausal women. One hundred and four women volunteers were randomized to dietary intervention or control groups. The dietary intervention included intensive dietary counseling to replace animal products with plant-based foods. Subjects in the dietary intervention group participated twice a week for 18 wk in workshops about the preparation and consumption of a plant food-based diet. The absolute change in serum total phytosterol concentration was greater in the dietary intervention group than in the control group. The percent change tended to differ between groups. However, only for beta-sitosterol did the absolute and percent changes within a group differ significantly between groups. The decrease in serum total cholesterol in the dietary intervention group (-14%) was greater than that in the control group (-4%). The results of this study show that circulating levels of phytosterols can be affected by dietary modification. These findings indicate that phytosterols, in particular beta-sitosterol, can be used as biomarkers of exposure in observational studies or as compliance indicators in dietary intervention studies of cancer prevention.

Antioxidant effects of phytosterol and its components.
J Nutr Sci Vitaminol (Tokyo). 2003 Aug;49(4):277-80.
Phytosterol contained in vegetable oils is known to exert a hypocholesterolemic function. In the present study, the antioxidant effects of phytosterol and its components, beta sitosterol, stigmasterol, and campesterol, against lipid peroxidation were examined. Taken together, the present study shows that phytosterol chemically acts as an antioxidant, a modest radical scavenger, and physically as a stabilizer in the membranes.

Effects of a new soy / beta-sitosterol supplement on plasma lipids in moderately hypercholesterolemic subjects. Cicero AF. University of Bologna, Italy.
J Am Diet Assoc 2002 Dec;102(12):1807-11.
Our aim was to test the cholesterol lowering effect of a low-dose formulation of soy proteins supplemented with isolated beta sitosterol in a ratio of 4:1 in 20 moderately hypercholesterolemic subjects. The study has been divided in three different periods of forty days each: a stabilization diet period, then a treatment period during which all subjects assumed 10 g one time a day of the tested product and, finally, a wash out period. From the end of the stabilization diet period to the end of the soy protein added in beta sitosterol supplementation we observed a decrease in LDL-C, TG and apoB levels, associated with a mean increase respectively in HDL-C and apoA plasma concentrations. According to this recommends, low doses of soy protein added in beta sitosterol seems to be a practical and safe alternative for patients seeking modest reductions in LDL-C (< 15%).