Beta sitosterol is a phytosterol-a plant compound with a chemical structures similar to that of cholesterol. Phytosterols inhibit the intestinal absorption of cholesterol.

Clinical trials have shown that eating foods enriched with at least 0.8 g of plant sterols or stanols helps to lower serum LDL cholesterol. Other studies have shown beta-sitosterol may help to fight cancer by causing apoptosis (cell suicide) in breast, colon and prostate cancer cells.

References

Berger A, Jones PJ, Abumweis SS. Plant sterols: factors affecting their efficacy and safety as functional food ingredients. Lipids Health Dis. 2004;3(1):5. Katan MB, Grundy SM, Jones P, Law M, Miettinen T, Paoletti R. Efficacy and safety of plant stanols and sterols in the management of blood cholesterol levels. Mayo Clin Proc. 2003;78(8):965-978. Nissinen M, Gylling H, Vuoristo M, Miettinen TA. Micellar distribution of cholesterol and phytosterols after duodenal plant stanol ester infusion. Am J Physiol Gastrointest Liver Physiol. 2002;282(6):G1009-1015. Jones PJ, Raeini-Sarjaz M, Ntanios FY, Vanstone CA, Feng JY, Parsons WE. Modulation of plasma lipid levels and cholesterol kinetics by phytosterol versus phytostanol esters. J Lipid Res. 2000;41(5):697-705. Normen L, Dutta P, Lia A, Andersson H. Soy sterol esters and beta-sitostanol ester as inhibitors of cholesterol absorption in human small bowel. Am J Clin Nutr. 2000;71(4):908-913. 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(1):171-177. Plat J, Mensink RP. Effects of plant stanol esters on LDL receptor protein expression and on LDL receptor and HMG-CoA reductase mRNA expression in mononuclear blood cells of healthy men and women. FASEB J. 2002;16(2):258-260. Mouritsen OG, Zuckermann MJ. What`s so special about cholesterol? Lipids. 2004;39(11):1101-1113. von Holtz RL, Fink CS, Awad AB. beta-Sitosterol activates the sphingomyelin cycle and induces apoptosis in LNCaP human prostate cancer cells. Nutr Cancer. 1998;32(1):8-12. Awad AB, Roy R, Fink CS. Beta-sitosterol, a plant sterol, induces apoptosis and activates key caspases in MDA-MB-231 human breast cancer cells. Oncol Rep. 2003;10(2):497-500. Choi YH, Kong KR, Kim YA, et al. Induction of Bax and activation of caspases during beta-sitosterol-mediated apoptosis in human colon cancer ce