Plant sterols and stanols: do they lower cholesterol? 

What are plant sterols and stanols?

You may have seen spreads or yogurt drinks in the supermarket that say they can help lower your cholesterol. This is because these products contain plant sterols and stanols (sometimes called phytosterols).

These are natural substances found in small amounts in plant foods, such as fruit and vegetables, wholegrains, vegetable oils, nuts and seeds.

They have a similar structure to cholesterol and can influence the way cholesterol behaves in the body.

The amount we naturally eat is quite low and not enough to have a big effect on cholesterol levels in the blood.

But some food manufacturers have fortified certain foods, like yogurts, yogurt drinks and fat spreads, with plant sterols and stanols to help people increase their intake.

Do plant sterols lower cholesterol?

There is strong scientific evidence that plant sterols and stanols can help lower blood cholesterol levels, including ‘bad’ non-HDL cholesterol.

They do this by reducing the absorption of cholesterol in the gut, so more cholesterol is removed from the body rather than entering the blood stream.

When taken in the right amounts (between 1.5g to 3g) every day, they can reduce cholesterol levels by 7 to 12 per cent. This effect can usually be seen within 2 to 3 weeks of continued use.

There is no benefit in taking more than 3g per day and it is not recommended.

Although they lower cholesterol, studies have not shown that plant sterols and stanols directly reduce the risk of heart attack or stroke.

Because of this, National Institute for Health and Care Excellence (NICE) guidelines in the UK do not recommend them specifically for preventing cardiovascular disease (CVD).

However, they are recommended in NICE guidelines as an option for people who have familial hypercholesterolaemia.

If you do use them, they need to be taken every day at the right dose, as their effect is lost when you stop.

They work differently from statins, which reduce the amount of cholesterol made by the liver.

This means that using plant sterols and stanols alongside statins can help lower cholesterol levels even further. However, they should not be used as a substitute for statins, which can achieve much larger reductions in cholesterol levels. 

Plant sterols and stanols lower cholesterol in a similar way to a drug called ezetimibe, by reducing cholesterol absorption in the gut. However, there is not enough evidence of an additional benefit from combining them.

So, if you are prescribed ezetimibe, taking plant sterols and stanols as well is likely to have a limited effect.

What’s the best time of day to take plant sterols?

For plant sterols and stanols to work effectively, they need to be taken with a meal as this is when the cholesterol absorption happens.

They can be taken in 1 single portion (for example, 1 yogurt drink) or spread across meals during the day (for example, 3 servings of fat spreads).

The key is to take them daily, in the right amount (a maximum of 3g per day) and with food for their cholesterol-lowering effect to be maintained.

What foods are fortified with plant sterols and stanols?

In UK supermarkets, you most often find plant sterols and stanols in:

• fat spreads (used like butter or margarine)
• yogurt drinks
• yogurt pots.

There’s no extra benefit from having more than 3g day and it is not recommended.

What are the side effects of plant sterols and stanols?

Foods fortified with plant sterols and stanols are generally considered safe for most people.

But they are not recommended for pregnant or breastfeeding women, or young children, because cholesterol is needed for growth and development.

These products are only advised for people with high cholesterol levels and should only be used as part of an overall healthy balanced diet rather than as a substitute for one.

Stanols and sterols may reduce the absorption of some fat-soluble vitamins, particularly carotenes (pro-vitamin A). But eating a healthy, balanced diet containing lots of red and orange vegetables will help provide sufficient carotenes.

People with a rare genetic condition called sitosterolaemia (where plant sterols build up in the body) should avoid taking plant sterol-enriched products.

Can plant sterols cause liver damage?

There is no evidence that long-term use of plant sterols and stanols, taken in the correct dose, is detrimental to health, including damage to the liver.

These products are approved on the EU and GB registers of health claims for their cholesterol-lowering effects.

Should you take plant sterol supplements?

While some plant sterol supplements may help reduce cholesterol, the strongest cholesterol-lowering evidence comes from foods fortified with plant sterols and stanols.

There is not enough evidence that supplements have a consistent cholesterol-lowering effect.

Fortified foods are regulated for dose and labelling, whereas supplements vary a lot in their dose per capsule, formulation and quality.

Always check with your GP before taking supplements as they may interfere with your medicines.

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