Plant Sterol 

What are plant sterols?

Plant sterols (or phytosterols) are cholesterol-like substances that are naturally present at low levels in many varieties of fruits, vegetables, nuts and cereals.

They can be extracted either from edible vegetable oils such as soybean or sunflower oil, or are obtained from a by-product of the pulping process used for coniferous trees.

Plant sterols are a natural part of the diet. From natural dietary sources, intake of plant sterols is between 0.3-0.6 grams per day, depending on the diet. Vegetarians may consume more plant sterols because of a higher consumption of fruits and vegetables.

Because plant sterols are chemically similar to cholesterol in animals, they have the ability to reduce absorption of dietary cholesterol, when eaten in sufficient quantities.

Table spreads with added plant sterols have been available for several years. Plant sterols may also be added to low-fat varieties of milk and yoghurt and can be incorporated into breakfast cereal.

What amounts of plant sterols are required for a cholesterol-lowering effect?

Plant sterols block the absorption of cholesterol from the intestine, but are not absorbed themselves to any significant extent. A small cholesterol lowering effect can be achieved when plant sterols are consumed in amounts between 1 and 3 grams per day. Plant sterols lower LDL cholesterol levels (bad cholesterol), but do not alter HDL cholesterol levels (good cholesterol) in the blood.

Can eating more plant sterols increase these effects?

A significant body of research has shown that plant sterols are safe even when consumed in amounts well above 3 grams per day. However, there is no increase in the cholesterol lowering effect of plant sterols when eaten in amounts above approximately 3 grams per day.

For a healthy diet, it is important to enjoy a variety of foods every day. A diet low in saturated fats and high in fruits, vegetables and wholegrain cereals is also a good choice when you have concerns about your cholesterol level.

Do plant sterols have other effects?

The safety of consuming up to 3 grams per day of plant sterols is well supported by the scientific evidence.

Because plant sterols lower cholesterol absorption, they can also lower the absorption of some fat-soluble vitamins. In particular, levels of beta-carotene are lowered when plant sterol enriched foods are consumed. Eating additional fruits and vegetables that are rich in beta-carotene may help to minimise this effect. Orange coloured fruits such as apricots, and vegetables such as pumpkin, sweet potato and carrots, as well as dark green leafy vegetables such as spinach and some Asian greens are good sources of beta-carotene.

Are there any health risks from eating plant sterol enriched foods?

People with a rare inherited metabolic disease called sitosterolaemia should restrict consumption of plant sterols. This disease affects a very small proportion of the population (about 1 in 6 million) and is managed under medical supervision. People with sitosterolaemia absorb high levels of plant sterols which can lead to premature atherosclerosis and heart disease.

What if I am taking medication to lower my cholesterol levels?

Plant sterol enriched foods may be consumed safely while you are taking cholesterol lowering drugs. However, plant sterols do not replace cholesterol lowering medication prescribed by your doctor. If you are already on cholesterol lowering medication, consult your doctor for advice about your diet and whether plant sterol enriched foods may provide any additional benefits.

Can children eat plant sterol enriched foods?

Generally there is no need to lower cholesterol levels in children. Plant sterol enriched foods are intended for adults who want to reduce their cholesterol level through changes in their diet.

Manufacturers are required to label their products so that consumers will know that plant sterol enriched foods are intended for adults, not children.

What if I am pregnant?

Plant sterol enriched foods have not been tested specifically in pregnant women. However, knowledge about plant sterols and the way in which they work in the body to reduce absorption of dietary cholesterol does not indicate safety concerns for pregnant or lactating women. Generally speaking, women who are pregnant or breast feeding do not need to be concerned about cholesterol and do not need to consume plant sterol enriched foods.

How will I know how much plant sterols are in a product?

Manufacturers must label plant sterol enriched products with the words ‘plant sterols’, ‘plant sterol esters’ or ‘phytosterol esters’. The label must also include the total amount of plant sterols added in grams per serving of food.

As a general guide, one cup (250ml) is regarded as one serving of low-fat milk, one serving of low-fat yoghurt is an individual punnet up to 200 g, and one serving of a muesli-type cereal is equivalent to about 45 g of cereal.

Are foods with plant sterols permitted in other countries?

In other countries, particularly in Europe, plant sterols are permitted in table spreads, milk, yoghurt and cheese products, some cereal products and spicy sauces, and rye bread (pumpernickel). In the US, plant sterols are also permitted in orange juice.


For more information on plant sterols see:

The National Heart Foundation of Australia’s website http://www.heartfoundation.com.au/downloads/PlantSterol_Aug03_final.pdf
The Dietitians Association of Australia website http://www.daa.asn.au/index.asp?PageID=2145842757