Naturally occurring plant sterols fool the body into getting rid of ‘bad’ cholesterol.
FOR the past 50 years, scientists have been assembling evidence that plant sterols, or phytosterols, have a significant
cholesterol-lowering effect. And since all of us have eaten some measure of plant sterol every day of our lives, its safety is without question. So it’s not a recent discovery that it takes sterols to combat sterols. That’s how plant sterols prevent animal sterols – the most familiar type being cholesterol – from being processed and absorbed in our bodies. When that happens, our low-density lipoprotein cholesterol (“LDL cholesterol” or otherwise, “bad” cholesterol) is lowered, and with it, our risk of contracting a cardiovascular disease (CVD).
What are plant sterols? According to Bruce German, professor in the department of food science and technology at the University of California, Davis, they occur naturally, in small amounts, in vegetables, fruits, legumes,
nuts and many other plant sources. Just as cholesterol is a component of animal cell membranes, plant sterols play a similar role in the cell membranes of plants.
While drugs are a convenient and quick-fix way to battle “bad” cholesterol, Dr German explains that drugs are not always the best answer. “Heart disease is not one thing gone wrong. It is a series of things building an insidious accumulation of cholesterol and fat in the artery walls. If you’ve got lots of things going a little wrong, drugs are not going to help. Drugs are only successful in addressing one thing at a time. And drugs come with side effects,” he said.
“The good news is food can address different things at one time. It’s the idea of using diet to work on several risk factors that offers a more holistic approach.” According to statistics from the World Health Organization, an estimated 7.2 million people died of coronary heart disease in 2004. By 2030, it is projected that 23.6 million people will die from CVD (mainly heart disease and stroke), with the largest increase in number of deaths projected to come from South-east Asia.
Vernon Kang, chief executive officer of the Singapore Heart Foundation, revealed that CVD is the No 1 killer in Singapore; CVD kills one out of every three Singaporeans. In the national health survey conducted in 2004, the percentage of Singaporeans aged 18 to 69 with borderline-high to high LDL cholesterol came up to an alarming 50 per cent.
So how do these magical plant sterols work to lower bad cholesterol? On the molecular level, animal cholesterol and plant sterols are very similar in their structure. When we consume plant sterols, our body is “fooled” into digesting them instead of cholesterol. As a result, the intestines absorb the plant sterols and then deliver them to our liver in exactly the same way as cholesterol is processed. But because our body has no use for plant sterols, our liver sends them back to our intestines.
While our body is being distracted by the plant sterols, the cholesterol is continuing through the intestines, into the colon and out through the faeces. In short, plant sterols act as a decoy. The net effect is that our body takes up less cholesterol because more is being passed out of the body. This can lead to lower LDL cholesterol over time. When we understand this unique system, we see why plant sterols need to be eaten during meals for maximum benefit. To do their job effectively, the plant sterols need to be in our small intestines together with cholesterol. In other words, we can literally eat our way to a healthier cholesterol level by ensuring we consume plant sterols during a meal.
Because plant sterols occur in such small amounts naturally, it is difficult to get a significant amount into our diet from foods we eat. That’s why scientists have formulated ways of incorporating plant sterols into foods that we consume on a daily basis – spreads, beverages and snacks. “Many clinical trials have been conducted on thousands of people and they have found that the amount of plant sterols necessary to see results is about 1.2g to 1.5g a day,” stated Dr German. The key factor is that plant sterols have to be consumed “regularly, once or several times a day, and with meals”.
In Singapore, Dr German has worked with Nestlé to introduce Singapore’s first and only adult milk which is fortified with plant sterols – Nestlé Nesvita Omega Plus Acticol. James Wong, director of corporate affairs and communications at Nestlé Singapore, disclosed that when 30 of Nestlé’s local employees consumed the recommended two cups a day with meals, there was an average drop of 5-7 per cent in their cholesterol levels, without any change in their dietary or lifestyle habits.
“Working long hours and stress can give rise to unhealthy dietary habits and sedentary lifestyles, factors ripe for the development of cardiovascular diseases,”
said Mr Kang. “The good news is if we control or manage those risk factors, that can be modified. We can promote and even enhance the health of our heart and so help prevent the onset of cardiovascular diseases in our lives.”
Benecol is another brand that produces a range of products like margarines, spreads, yoghurts and yoghurt drinks which contain cholesterol-lowering plant sterols. Yoplait is also another example. A six-ounce serving of Yoplait Healthy Heart yogurt, for instance, provides 0.8g of plant sterols – the equivalent of 26 oranges, 44 apples or 70 large carrots. As a snack, Nature Valley Healthy Heart granola bars provide 0.4g of plant sterols per serving.