Beta-sitosterol is a plant sterol that lowers serum cholesterol.
Plant sterols are produced in the refinement of vegetables or as a byproduct of papermaking from the oil of pinewood.
Beta-sitosterol's chemical structure is actually similar to cholesterol, but it does not create an increased risk of atherosclerotic and/or heart a disease. The average diet provides about 175 to 200 mg of Beta-sitosterol, but less than 5 percent is actually absorbed when consumed orally, so to lower cholesterol effectively you need to take a Beta-sitosterol supplement.
Beta Sitosterol is commonly added to margarines as a cholesterol-reducing aid. Fats are needed to solubilize plant sterols, so margarines are an ideal vehicle. Smart Balance, which contains plant sterols, claims to reduce cholesterol and thereby decrease the risk of heart disease. It is most unlikely and you should not rely on this food product to lower cholesterol. Beta-sitosterol actually inhibits intestinal absorption of cholesterol by about 50 percent.
Taking beta-sitosterol orally significantly reduces total and low-density lipoprotein (LDL means "bad") cholesterol levels, but has little or no effect on high-density lipoprotein (HDL means "good") cholesterol levels. I have yet to read of studies that quantify if consuming Beta-sitosterol can decrease the number of worrisome small LDL particles.
It is usually well tolerated, but, in some patients it can cause nausea, indigestion, gas, diarrhea or constipation. If you are taking a prescription cholesterol-lowering agent, know that Zetia, Pravachol and other statin drugs may significantly inhibit intestinal absorption of Beta-sitosterol.
Beta-sitosterol may decrease Vitamin E and the carotenes absorption. Although a statin drug and Beta-sitosterol could work synergistically, I tell my patients to first try 300 mg a day of Beta-sitosterol and in 3 months, I recheck their serum lipids (fats like cholesterol and triglycerides).
I recommend 300 mg a day of Beta-sitosterol taken at least 30 minutes before a meal.