Greatest amounts occur in vegetable oils with smaller amounts in nuts, legumes, breads and cereals, and in still smaller amounts in fruits and vegetables. Plant sterols used in foods are extracted as by-products of wood pulp or soybean processing. Plant sterols have been found in food products manufactured in Australia and New Zealand since 1999. Other countries have food products containing sterols as well as its hydrogenated version, the stanol.
Plant sterols can stop cholesterol from being absorbed from the digestive tract into the body.
To be absorbed, cholesterol normally mixes with other substances to form what is known as a micelle, which then allows it to pass into the blood stream. Plant sterols, because they are closely related to cholesterol, actually compete with cholesterol for a place in the micelle. If a cholesterol molecule can t find a place in the micelle, it is not absorbed and simply passes out of the body with other bowel wastes. If eaten in sufficiently high enough quantities, sterols have been proven to lower blood cholesterol, particularly the bad LDL-cholesterol. The average person usually consumes about 0.25 g of plant sterols daily.