If you’re conscious about the food products you buy at the supermarket, you probably would have started to notice the words “contains plant sterols” appearing on some of them. From margarine spreads and even fortified milk for adults, these products claim to help lower your cholesterol.

But what exactly are plant sterols and can they really lower your bad cholesterol (LDL cholesterol)? Dr Tan Hong Chang, Consultant at the Department of Endocrinology, Singapore General Hospital (SGH), a member of the SingHealth group, helps us answer a few questions.

Plant sterols and their health effects

What are plant sterols and how do they reduce your LDL cholesterol?

Plant sterols are substances that occur naturally in small amounts in many grains, vegetables, fruits, legumes, nuts and seeds. On a molecular level, plant sterols look a lot like the cholesterol you get from eating animal products such as meat, chicken, fish, eggs, butter, cheese and whole milk. As a result, they may interfere with cholesterol absorption and lower cholesterol levels.

However, for plant sterols to make any difference to a person’s cholesterol levels, they need to be consumed in large quantities. Dr Tan says, “Studies examining the cholesterol-lowering effects of plant sterols contained 2 to 30 times the average amount of plant sterols found in an average Western diet.”

How much plant sterols should you consume daily?

According to short term studies involving fortified margarine, a daily intake of between 0.8g to 3g of plant sterols lowered bad (LDL) cholesterol by a modest 10 to 20 per cent, without affecting good (HDL) cholesterol, says Dr Tan.

He adds, “This effect was observed predominantly in the first three months, although the decrease may continue over time.”

Are plant sterols effective in preventing heart disease?

Most studies conducted on plant sterols have been short-term (less than a year). Compared to established medical therapy for lowering cholesterol, no studies have demonstrated clinical benefits of plant sterols, such as reducing heart attacks and strokes or preventing death.

Could plant sterols have any negative effects in the long run?

Such negative effects cannot be ruled out entirely because most plant sterol studies conducted so far have only been short term. No study has confirmed the lack of ill effects either.

Dr Tan adds, “Potential long-term concerns include the impact of plant sterols on fat-soluble vitamins and anti-oxidant levels. Furthermore, patients with a very rare inherited plant sterol storage disease (called sitosterolemia) already have high levels of plant sterols in their blood. Hence, they should avoid supplementing.”

If you’re unsure if you have such a condition, first consult your doctor or dietitian before making any dietary changes. Also, just because a food product contains plant sterols, it doesn’t necessarily mean that consuming plenty of it is good for you. Always check the food label carefully, as the food could contain excess calories and sugars.

Ref:​ S13