Cholesterol is a hidden danger. A quick pinch around the middle tells us if we’ve been piling on the pounds, but says nothing at all about the state of our arteries. “There are no outward symptoms,” says Dr Anthony Wierzbicki, chairman of Heart UK’s medical committee. “You can be fat. You can be thin. Either way you can have high cholesterol.”

The only way to know for sure is to take a blood test. It may not even mean a trip to the doctor’s: home-testing kits are quite reliable. More of us in the UK die from coronary heart disease than any other condition, and high cholesterol is recognised as a risk factor. So we should probably be more clued up. Especially since the nation’s average cholesterol level is estimated at 5.5 and anything over five is considered a potential problem.

“In the US almost everyone can tell you their numbers for cholesterol,” says Dr Wierzbicki. “In the UK, people don’t seem interested. We leave things to fate.”

Or perhaps we’re simply baffled. Cholesterol is complicated. Heard about “good” and “bad” cholesterol? Know the difference? Not many of us do, but basically cholesterol is not, in itself, the villain it is made out to be. It’s a lipid, or body fat, produced in the liver, which is vital for healthy cells and digestion. When it joins forces with proteins in the right proportions, it forms “good” cholesterol that can help the body deal with fat. It is “bad” cholesterol that we need to look out for: too much of that in the bloodstream can build up on artery walls, making them a tight squeeze.

That excess cholesterol can come from the food we eat. The general view is that reducing our intake is a healthy move, which means watching our diet. But the good news is that burgers, cheese and eggs can stay on the menu. You just need to be sensible. Even a 10 per cent reduction in your cholesterol level can reduce the risk of heart disease by 40 per cent.

The usual advice is to cut back on fat, while tucking into more fish, grains and pulses. Vegetarians have low cholesterol and vegans lower still, so there’s a strong case for eating less meat and dairy. And you could buy spreads and yoghurts that contain cholesterol-reducing plant extracts. Evidence suggests they work.

Even a lettuce leaf diet might not be enough: you can inherit high cholesterol levels along with the family silver and medical conditions can also take their toll.

Anne Sharple, a secondary teacher in Glasgow, was “gutted” to find her cholesterol was high and completely changed her diet. “I’ve been able to reduce it a little, but it turns out there’s an underlying problem with my thyroid, and I need to tackle that before I can go any further.”

Dr Wierzbicki says we should think about limiting our cholesterol consumption, whether or not we’re under doctor’s orders. “The most sensible thing is to make small alterations to your diet early in life,” he says. “It’s better than having to take drastic steps later on.”

Keep cholesterol at bay

- Cholesterol levels change quickly. Have an annual check.

- Home-testing kits are accurate to within 15 per cent, but lab tests give more detailed feedback.

- Cut out biscuits and crisps. Cut back on meat, eggs, liver and shellfish.

- High cholesterol is just one risk factor for heart disease. You are also advised to exercise, stop smoking and get your blood pressure checked.