Why is high cholesterol a problem?
The main risk associated with high cholesterol is cardiovascular disease (CVD). This includes diseases of the heart and blood vessels. High cholesterol causes blood vessels to become narrowed with fatty deposits called plaques. This can result in heart attacks, strokes and blood vessel problems. For more information see the separate Bupa health factsheets Angina, Heart attack and Stroke.
Types of cholesterol
Cholesterol is transported around the body in the blood attached to a protein. This combination of fat and protein is called a lipoprotein. Lipoproteins can be high density (HDL), low density (LDL) or very low density (VLDL), depending on how much protein there is in relation to fat.
What causes high cholesterol?
There are several factors that may contribute to high blood cholesterol:
- a diet that's high in saturated fat and, less so, high in cholesterol (see How diet affects cholesterol below)
- lack of exercise may increase LDL ("bad") cholesterol and decrease HDL ("good") cholesterol
- family history - people are at a higher risk of high cholesterol if they have a direct male relative aged under 55 or a female relative aged under 65 affected by heart disease
- being overweight, which may increase LDL ("bad") cholesterol and decrease HDL ("good") cholesterol
- age and sex - cholesterol generally rises slightly with increasing age, and men are more likely to be affected than women
- drinking more than the recommended amount of alcohol (ie more than three to four units per day for men and two to three units per day for women)
Rarely, high cholesterol can be caused by a condition that runs in the family called a lipid disorder (familial hypercholesterolaemia). About one in 500 people have this condition.
Other health conditions such as poorly controlled diabetes, certain kidney and liver diseases and an underactive thyroid gland may also cause cholesterol levels to rise. Some medicines such as beta-blockers, steroids or thiazides (a type of diuretic) may also affect blood lipid levels.
How diet affects blood cholesterol
Only a small amount of cholesterol comes directly from your diet - the majority is produced by your liver. However, if your diet is high in saturated fats and cholesterol this can cause your liver to produce more LDL ("bad") cholesterol. The amount that diet influences cholesterol levels varies from person to person.
Having a high cholesterol level does not cause symptoms. Most people find out they have high cholesterol when they have their blood cholesterol measured as part of a medical check-up. Alternatively, it may be identified after other health problems, such as heart disease, have been diagnosed.
The main aim of lowering cholesterol is to reduce the risk of heart disease. The type of treatment depends on the overall risk of heart disease.
There are two ways to help lower high cholesterol. The first is with simple lifestyle changes including changing diet, managing weight and increasing exercise. The second is to combine lifestyle changes with cholesterol-lowering medicines.
Healthy eating can reduce cholesterol. Your diet should be low in saturated fats in particular, and low in fat overall. Biscuits, cakes, pastries, red meat, hard cheese, butter and foods containing coconut or palm oil all tend to be high in saturated fats, so cut down on these foods.
Large amounts of cholesterol are found in a few foods, including eggs, offal such as liver and kidneys, and prawns. However, if you're already eating a balanced diet, you don't need to cut down on these foods unless your GP or dietitian have advised you to.
It's also important to eat plenty of fibre, especially soluble fibre, which is thought to lower cholesterol. It's found in fruits and vegetables, beans and oats. Aim to eat at least five portions of fruit and vegetables each day. For more information see the Bupa factsheet, Healthy eating.
There is some evidence that foods containing substances called plant sterols or plant stanols, such as the brands Benecol or Flora pro.activ, in combination with a low fat diet and physical activity, can help to lower cholesterol.
Cholesterol-lowering medicines are considered for people who already have CVD, or are at high risk of getting it because they have other risk factors.
The main group of medicines for lowering cholesterol are statins. Examples include simvastatin (Zocor) and atorvastatin (Lipitor). They work by reducing the production of cholesterol in the liver. Occasionally these drugs have side-effects such as indigestion and muscle pains. Other types of drugs to reduce cholesterol are called fibrates, nicotinic acids and cholesterol absorption inhibitors such as ezetimibe (Ezetrol) but these are generally less effective or have more side-effects. Your doctor will tell you more about these medicines.