Sitosterol

Question:
"Can you please share with me information about sitosterol? What is it and what does it do? Also, does it mimic estrogen and bind with estrogen receptors, thus lowering the production of estrogen like soy products do for women over 35?"

our Health Coach Answer:
Beta-sitosterol belongs to the family of plant sterols. Plant sterols are found natrurally in small quantities in many fruits, vegetables, nuts, seeds, cereals, legumes, vegetable oils, and other plant sources. Another group of compounds related to sterols and known as plant stanols, occur in even smaller quantities in many of the same food sources. Both stanols and sterols are essential components of plant cell membranes and resemble cholesterol.

Cholesterol, as the name suggests, is itself a sterol. Cholesterol is essential for life, since it is a building block for steroid hormones, such as testosterone and estrogen, and for cell walls. However high cholesterol, particularly low-density lipoprotein (LDL) cholesterol combined with other dietary and environmental stressors, can result in heart disease.

The cholesterol-lowering potential of dietary plant sterols and stanols has been known for over 50 years. However, the exact mechanism of how this is accomplished has only recently been revealed. Since plant sterols resemble cholesterol to such a great extent, they in effect compete for the limited absorption sites of cholesterol within the intestinal tract, thereby lowering serum cholesterol.

Recent areas of research reveal plant sterols also possess anti-cancer, anti-inflammatory, anti-atherogenic (preventing atherosclerosis or hardening of the arteries), and antioxidant properties and should thus be of clinical importance from a prevention standpoint. Interestingly enough, a powerful mechanism by which beta-sitosterol can protect against cancer is through down-regulation of cholesterol synthesis, emphasizing the importance of therapeutic lifestyle changes.

In a recent study, plant sterol-fed mice, had a 33 percent smaller tumor size and 20 percent less metastases in lymph nodes and lungs than cholesterol-fed mice when exposed to human breast cancer cell lines! This finding implies the possibility that plant sterols may in fact retard the growth and spread of breast cancer cells.

In another study it was found that women with the highest quartiles of total dietary intakes of plant sterols (>122 mg/day) had a reduced risk of endometrial cancer and an intake of more than 521 mg/day reduced risk of ovarian cancer.

While plant sterols may ultimately lower estrogen levels, the lowered levels have no clinical effect. In other words, the effect is beneficial on a cellular level but not from a symptom standpoint.

Phytosterols represent a new class of functional foods that have served to protect populations of people even before the exact mechanism was understood. Because of the health benefits they provide, plant sterols are further proof that your mother was right when she said "eat your vegetables".

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