You may have heard of someone avoiding types of food like eggs because he thinks his cholesterol level will go up after eating them.

For sure, high cholesterol levels will put you at risk of coronary heart disease, heart attack and stroke, but dietary cholesterol does not raise your blood cholesterol as much as large amounts of saturated fats do.

Cholesterol is a waxy, fat-like substance that is made and used by our bodies to make some hormones, vitamin D, bile and other substances.

It is also found in foods from animal sources, such as meat, poultry and full-fat dairy products.

When we eat a diet high in saturated and trans fats, our livers will produce more cholesterol.

Many people do not know whether their cholesterol level is too high as the high levels do not cause symptoms. A blood test will tell you if your cholesterol level is too high. You can control your cholesterol level with a healthy diet and regular aerobic exercise, though some people will also need to take medications.

Let's take a closer look.

Q How does high cholesterol affect you?

A Excess cholesterol in your blood will build up in the walls of your arteries and this plaque will make it harder for your heart to circulate blood. A heart attack or stroke can occur from sudden blood clots in these narrowed arteries.

Cholesterol is transported through your bloodstream by carriers called lipoproteins, of which the two main types are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).

LDL is the bad cholesterol as it carries cholesterol to the tissues, including the arteries, and elevated levels of LDL are strongly linked to increased cardiovascular risk.

HDL is considered "good" cholesterol because it transports cholesterol back to the liver, where it is passed from the body.

Q What types of food should I stay away from? What about eggs?

A Cholesterol levels can certainly be lowered by dietary changes, especially by avoiding red meat, butter, fried foods, cheese and other foods that have a lot of saturated fat, said Dr Rohit Khurana, a cardiologist at Gleneagles Hospital, Singapore.

Also, restrict your intake of sugar, sweets and refined grains which are found in white bread, white rice and most forms of pasta.

Eggs are fine. "Eggs are one food which are consistently vilified because of the high cholesterol content of yolks, but moderate consumption, up to one a day, is acceptable and is safe for the heart," said Dr Khurana. Egg whites are also a valuable protein-rich food.

Q What's a good diet to follow?

A A Mediterranean diet appears to reduce the risk of cardiovascular events, said Dr Khurana.

The diet typically consists mainly of fruit and vegetables, whole grains, beans, nuts, seeds and olive oil as an important source of fat. It also usually includes low to moderate amounts of fish, poultry and dairy products, and little red meat.

Q When do I need statins?

A Statins are drugs that can block a substance your body needs to make cholesterol. "Several trials have unequivocally demonstrated the benefit of statins in patients with coronary artery plaque disease and especially in those who have suffered a heart attack," said Dr Khurana.

The decision to start statins is made after a personalised assessment of the patient's overall cardiovascular risk, he said.

So, if your long-term risk of experiencing a heart attack or stroke is high, for instance, statins may help.

Q Can I stop taking statins after being on it?

A Yes, you can but, in practice, stopping treatment usually results in a rise in cholesterol levels, despite the motivation to maintain an active lifestyle, with sustained exercise and dietary change, said Dr Khurana. "Although medications can rapidly lower your levels, it often takes six to 12 months before the effects of lifestyle modifications are noticeable," he said.

The treatment of high cholesterol - and triglycerides, a type of fat that contributes partly towards your total cholesterol count - is a lifelong process. It is thus important to stick with the treatment plan once you begin to see results, he said.

Most people who request to discontinue their statin treatment do so because of the side effects, he added. "However, there is a wide variety of alternative medication that should suit the vast majority of patients."

Q What are the side effects?

A Statins are generally very safe, though some people do not tolerate them well. Some common side effects include muscle and joint pain, nosebleeds, sore throat, headache and problems with the digestive system like diarrhoea, according to Britain's National Health Service.

Adverse muscle toxicity or myopathy is a rare but major side effect, affecting less than 0.1 per cent of patients taking a statin. It is also a dose-dependent phenomenon, said Dr Khurana. Muscle symptoms usually begin within weeks to months after starting statins.

There is some evidence that Chinese individuals are more susceptible to statin-induced myopathy than Western populations, so higher doses of statins are less commonly prescribed in Singapore, Dr Khurana said.

Also, liver problems can happen but are rare. Cognitive impairment like memory loss and confusion is another side effect that has been reported. The US Food and Drug Administration said these experiences are rare. Furthermore, the symptoms were not serious and were reversible within a few weeks after the patient stopped using the drug.

Q Will statins give me diabetes?

A Statins may also confer "a small increased risk of developing diabetes" and this risk becomes slightly greater with high doses than moderate doses, said Dr Khurana.

However, there is overwhelming evidence from clinical trials that shows that statins reduce heart attacks in patients with and without diabetes, he said. The beneficial effects of statins on cardiovascular protection thus far outweigh the increased risk.