Question: I don’t use butter or butter substitutes on my bread, but are the new spreads that claim to actively lower cholesterol absorption better than using nothing?
Answer: Fortunately, we have many tasty alternatives to butter in the form of vegetable-oil-derived spreads. Among them is a small group, such as Flora pro-activ and Logicol, that contain plant sterols and come with claims that they lower blood-cholesterol levels. This sounds really positive, as high blood cholesterol levels are associated with an increased risk of cardiovascular disease.
So, should we all use special spreads to lower our cholesterol levels? When we eat food containing cholesterol, the cholesterol travels through our stomach to the small intestine where it mixes with bile from our liver and gall bladder to form micelles. These micelles are then absorbed through the wall of the small intestine, where, after a little more processing, a significant proportion enters our circulation.
Plant sterols have a similar structure to animal-derived cholesterol, and this physical similarity can work in our favour. This is because when we consume food containing plant sterols, the sterols compete with cholesterol for space in the micelles. And because there are limited spaces in the micelles for cholesterol, the more plant sterols that steal spaces, the less cholesterol we absorb from our diet and other sources, and consequently the lower the circulating level of cholesterol.
Myriad clinical trials have shown that regular consumption of plant sterols lowers blood cholesterol levels. A daily dose of about 2.15g of plant sterols can reduce “bad” LDL cholesterol levels by about 9%, according to a 2009 metaanalysis in the Journal of Nutrition. Given that a 1% reduction in LDL levels equates to about a 2% reduction in cardiovascular disease risk, plant sterols can have a significant effect on our health risk.
Plant sterols naturally occur in some fruits, vegetables, grains, nuts, seeds and their oils, but these foods don’t provide enough of them to have a significant effect on cholesterol levels. This is why table spreads enriched with plant sterols are a great option for people who need to lower their cholesterol levels.
Typically, about five teaspoons, or 25g, of spread provides the recommended 2g of plant sterols a day (as 100g of these spreads generally contains about 8g of plant sterols). And it’s important that you consume the recommended 25g of spread a day, as any less won’t provide the full effect.
However, more is not better in this case, as consuming a greater quantity of plant sterols will have no further significant effect on cholesterol levels. The other good news is that the effect of plant sterols on cholesterol levels works independently of other dietary changes aimed at reducing cholesterol levels.
In other words, the positive effects of plant sterols on cholesterol levels are additional to the positive effects that would result from reducing your saturated fat intake by cutting the fat off your steak, removing the skin from chicken and choosing low-fat dairy products, according to a 2009 study published in Lipids.
So, should we all grab ourselves a tub of plant sterol-enriched margarine? The answer depends on your health. If you have high cholesterol levels, using a spread containing plant sterols would be helpful. But if you have normal, healthy cholesterol levels, there is nothing to gain from using these spreads, particularly given they cost at least twice as much as standard spreads.
It’s also worth noting that in addition to reducing the absorption of cholesterol, plant sterols also make it slightly harder to absorb certain fat-soluble nutrients such as beta-carotene, which our body uses to make vitamin A. Although this isn’t likely to have a significant effect on people who use these spreads regularly and have an otherwise healthy diet, it reinforces the point that there is little to gain and potentially a bit to lose, financially and nutritionally, by using these spreads when they aren’t required.
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