Cholesterol lowering margarines
1 March 2002
Margarines that claim to help reduce cholesterol can now be found on any supermarket shelf. Find out whether the hype about sterol-enriched foods as an aid to lowering your cholesterol is justified.
If the marketing hype is to be believed, the future of cholesterol lowering lies in a tub of margarine — not a bottle of tablets.
Margarines containing plant sterols have emerged as one of a new group of 'functional foods' that are being heavily promoted as the drug-free way to tackle medical problems such as high cholesterol.
And while Australian medical authorities agree that dietary factors do influence cholesterol levels, they worry that the marketing hype risks overstating the benefit of these products.
'There is a concern that people think that these foods are a cure-all and they might take it out of the context it was initially intended for,' warns Nutrition Australia senior nutritionist Aloysa Hourigan.
She said margarines made with stanols and sterols could help lower cholesterol levels by about 10 per cent — hardly enough to 'cure' most people who have seriously high cholesterol levels.
Clinical trials into sterol-enriched foods have demonstrated that a daily intake of 2 g of plant sterols and stanols can reduce LDL cholesterol (low-density lipoprotein cholesterol, the so-called 'bad' cholesterol) by 10 to 15 per cent, and that this effect is in addition to reductions caused by a modified diet or medication such as statin tablets.
They work by reducing the absorption of cholesterol from the intestine, whether it be dietary cholesterol (cholesterol that is eaten in the diet) or biliary cholesterol (cholesterol that is produced by the liver and secreted as a component of bile into the intestine).
In other words, Ms Hourigan said, sterol-enriched foods can be used in addition to — but not instead of — the dietary, exercise and other lifestyle changes and medication therapy that most doctors recommend to help reduce cholesterol.
What the evidence shows
- Plant sterols, extracted from coniferous trees, have been shown to reduce the amount of dietary and biliary cholesterol absorbed by the human body.
- A daily dose of 2 g was found to reduce LDL cholesterol by 10 to 15 per cent, in addition to reductions achieved through modified diet or statins.
- Available in Australia only in margarines, a daily intake of 2 to 3 g (about one-and-a-half tablespoons) of sterol-enriched spread is recommended.
- No adverse effects were reported, but plant sterols can reduce gut absorption of carotenoids, such as beta-carotene. Beta-carotene is an antioxidant which is believed to protect cells against damage that can lead to cancer. Beta-carotene is converted to vitamin A in the body, as needed. As a result, they are not recommended for children or pregnant/lactating women.
- People using these spreads should be encouraged to eat more yellow and orange fruit and vegetables, which are good sources of beta-carotene.
Source: National Prescribing Service
Healthy fats
With 6 million adult Australians believed to have high cholesterol levels (total cholesterol more than 5.5 mmol/L), the potential market for cholesterol-lowering functional foods is extensive.
Indeed, food manufacturers have been pushing claims that their products are 'clinically proven to lower cholesterol' using slick advertising campaigns.
And the evidence is hard to fault. Even organisations such as the National Heart Foundation (NHF) and the Cardiac Society of Australia and New Zealand concede, in their latest lipid guidelines, that 2 to 3 g daily of these products can lower cholesterol levels by 10 to 15 per cent. In fact, the NHF has added its tick of approval to the labels on 2 so-called cholesterol-lowering margarines.
But the Foundation's national nutrition manager Susan Anderson said that its endorsement of the products was not in support of their cholesterol-lowering claims, but because they contained healthy fats.
'We endorse the margarines Logicol and Pro-activ on the basis of the fatty acid profile of the margarine because they are predominantly based on poly- and mono-unsaturated fats and they are reduced in salt so they meet the Heart Foundation's criteria,' she said.
This year, the NHF is working with the National Prescribing Service to promote the message that people should eat healthy fats instead of following a low-fat diet. Margarines with plant sterols fall into that 'healthy fats' category.
The NHF is also providing doctors with the latest information on dietary and lifestyle changes for cholesterol management, so ask your doctor for advice.
Food labelling
The council advising the Australia New Zealand Food Authority (ANZFA) first approved the use of plant sterols derived from vegetable oils in margarines in June last year, albeit with some reservations.
ANZFA called for mandatory labelling that these foods were not recommended for infants, children and pregnant or lactating women and that people using cholesterol-lowering drugs should seek medical advice before using the spreads.
ANZFA spokeswoman Lydia Buchtmann said these requirements were made after the plant sterols had been assessed for their safety, and not for their health claims.
'They have to be labelled as not suitable for children or pregnant or lactating women because they reduce the uptake of beta-carotene,' she said.
'They also have to advise that people using cholesterol-reducing medication should seek medical advice before using the spreads. That was due to medical concerns that people would stop using their medication.'
Although ANZFA approved the margarines, it recalled snack bars, yoghurt and salad dressings containing the same ingredients from supermarket shelves because it decided there was enough evidence only to support the safety of the margarine, and not these other products.
Head of the lipid clinic at Sydney's Royal Prince Alfred Hospital, clinical associate professor David Sullivan, was involved in the research of plant sterols in some of these food products.
He said further evidence was now being generated to support the safety of products other than margarine, which was important because many Australians were no longer using spreads.
'I think the expectation was that these people are going to love being encouraged to use margarine again because they've been told to restrict it, but we've actually altered people's habits to the point where many of them don't want it back again,' he said.
While he welcomed the introduction of functional foods that were backed up by reliable research, Professor Sullivan agreed that extending the range of products containing plant sterols raised some important questions. Most importantly, he said consumers needed to be told how much could be safely consumed — especially as it was known that sterols were slightly absorbed into the bloodstream and that they lowered beta-carotene levels.
He said research showed that the benefit on cholesterol levels from consuming plant sterols plateaued at about 1.5 to 3 mg a day, indicating the need to print recommended daily limits on food labels.
'I think in addition to labelling, the food regulatory authority is going to ask for evidence that taking 3 or 4 times the recommended amount is still not going to cause any immediately perceptible problems,' he said.
Professor Sullivan said patients who were borderline or fully indicated to receive cholesterol-lowering treatment would get most benefit from these spreads.
'I think it would be particularly useful for people who are on that borderline between drug treatment or [cholesterol-lowering] diet alone,' he said.
'It might just help them move more comfortably out of that grey zone into a group who don't require treatment for the time being.
'The second group [to benefit] would be those having an inadequate response to statin therapy.'
Nutrition Australia's Aloysa Hourigan said she recommended the margarines to some patients on a cardiac rehabilitation programme.
'When I talk about these margarines, I tell patients to put them in as part of their total diet, but not as something to go and use and expect their cholesterol to go right back to normal,’ she said.
'I always emphasise to people that it lowers it only by about 10 per cent; it doesn’t lower it from 7.0 mmol/L to under 3.0 mmol/L.'
She said a borderline patient with a LDL reading of about 4.0 mmol/L might try using those margarines to see if they could lower their level by 10 per cent, which would be beneficial.
'It could be something that gives you a bit of a winning edge,' she said.
If you believe that you could benefit from using 'cholesterol-lowering' margarines, and particularly if you are taking medication to lower your cholesterol, talk to your doctor to discuss your particular cholesterol profile before taking any action.
Louise Pemble
Last Reviewed: 05 March 2002
- Medical Observer 1 March 2002
