He's fit but he's got the wrong fat

Cholesterol is not that interesting to the average Brit. Most Americans can quote their blood LDL levels faster than they can order a takeaway, but we don't even know what LDL means. And we're puzzled by the new, cholesterol-lowering spreads. They cost twice as much as butter, taste funny and make hot toast go soggy. But given that every four minutes one of us keels over dead from a heart attack, should we buy them?

Sir Steve Redgrave, the new face of cholesterol-lowering Flora pro.activ, is certainly eating the stuff. Redgrave seems like the epitome of good health, having trained for 30 hours a week for 25 years and won five consecutive Olympic gold medals for rowing. He's been called "the fittest man in Britain", yet he discovered last November that his cholesterol was high - 6.2mmol/litre. "I was very, very surprised," he says. "Since I've been using Flora pro.activ it's gone down to 5.5mmol/litre", which is better, but still higher than the international target level of 5mmol/litre.

Cholesterol is a waxy white fat made mostly in the liver. It's an important component of all tissues in the body, but in excess it can build up and damage the arteries, causing heart attacks and strokes. It's a myth that cholesterol-containing foods like eggs, liver and prawns raise blood cholesterol substantially - the liver compensates by producing less. It is also a myth that cholesterol can be controlled just by diet - genetic predisposition plays a not-easily quantifiable part. But there are lifestyle habits that can make cholesterol a problem.

"Cholesterol does not dissolve in the blood," says Belinda Linden, medical spokeswoman at the British Heart Foundation. "It gets carried around by proteins to form a lipoprotein. 'Bad' cholesterol is low-density lipoprotein [LDL] and harms artery walls. Smoking and saturated fat raise bad cholesterol. 'Good' cholesterol is high-density lipoproteins [HDL], which carry excess cholesterol back to the liver for disposal. Moderate drinking [one-two units of alcohol per day] and exercise raise HDL."

Cholesterol and heart disease are not inextricably linked - obesity, inactivity, smoking, diabetes and high blood pressure all affect your risk - but raised cholesterol is not a good thing.

A new range of spreads, which includes Benecol (£2.49 for 250g) and the forthcoming Marks and Spencer Food and More products as well as Flora pro.activ (£1.95 for 250g), has been clinically proven to lower cholesterol. The spreads contain plant sterols and stanols which stop cholesterol being absorbed in the gut. M&S has used soya protein, which is believed to work largely by reducing cholesterol produced by the liver.

Clinical trials have shown that, eaten daily, all these products can lower LDL by 10-15 per cent in three weeks (in people who had high LDL). These are clinically significant results: 'This could reduce the risk of coronary heart disease by up to a quarter," says Dr Andrew Neil, of the Radcliffe Infirmary in Oxford. And it is not hard to eat a clinically significant daily amount: four pieces of bread use 20g of Flora pro.activ. From the M&S Food and More range you'd need to eat four portions of, for example, cereal bars, smoothies and pasta sauces (don't worry, they're delicious).

But should you buy them? "The first step for anyone with a cholesterol problem must be eating plenty of fruit, vegetables and fish, and lowering intake of saturated fat in things like biscuits, dairy products and fatty meat," says Belinda Linden. "Stopping smoking and starting exercising are also important." The BHF has found that some doctors have started advising spreads for people with a genetic predisposition to cholesterol, but eating the spreads "just in case" is not necessarily worthy.

"It's not a case of the lower the better," says Wendy Doyle, of the British Dietetic Association. "Keeping cholesterol within recommended limits is all you need to do." And while the spreads lead you to expel cholesterol, fat-soluble vitamins A, D, E and K go with them. This can be compensated for by having an extra portion of coloured vegetables a day (sweet potatoes or broccoli, for instance), but if you don't have a problem, why bother?

So what should you put on your bread? There is no strong evidence that olive oil-based spreads are better than any other monounsaturated or polyunsaturated spreads such as Flora. (Our perception of olive oil being good for us has more to do with the EC olive oil lake than scientific fact: it is the fruit-and-veg-rich Mediterranean diet as a whole that is good for your heart, not just olive oil). But they are all better than butter. "Butter is one of the main sources of saturated fat," says Doyle. "But it tastes good. If you're otherwise healthy I'd recommend you limit it to toast, where you can taste it, and use polyunsaturates and monounsaturates the rest of the time." Spread the word.

For lifestyle information about heart disease ring the automated British Heart Foundation helpline: 0870 6006566.