Cholesterol is a member of a group of fat substances also known as ‘lipids’. Lipids are important for the normal functioning of the body. Cholesterol is produced naturally by the liver, but can also be found in some of the food we eat every day.
Having too much cholesterol in your blood can however be very bad for your health. High cholesterol on its own does not cause any symptoms, but it increases your risk of serious health conditions such as heart disease, stroke and kidney failure, especially in people who already have a personal or family history of hypertension or diabetes.
Cholesterol is carried in your blood by proteins, and when the two combine they are called ‘lipoproteins’. There are harmful and protective lipoproteins known as HDL and LDL, otherwise known as ‘good’ and ‘bad’ cholesterol respectively.
- Low-density lipoprotein (LDL otherwise known as ‘bad cholesterol’) carries cholesterol from your liver to the cells in your body that need it. If there is too much cholesterol for the cells to use, it can build up and damage the artery walls, leading to disease of the arteries.
- High-density lipoprotein (HDL otherwise known as ‘good cholesterol’) carries cholesterol away from the cells and back to the liver, where it is either broken down or passed out of the body as a waste product. For this reason, it is referred to as “good cholesterol”. The more of this type of cholesterol you have, the better for your overall health.
The amount of cholesterol in the blood can be measured by means of a simple blood test. The recommended level of cholesterol in the blood will vary between healthy adults according to individual (and family) history, and also depending on other risk factors that you may have.
A high level of cholesterol greatly increases the risk of developing:
- hardening and narrowing of the arteries (atherosclerosis)
- angina and heart attack
- stroke and mini-stroke (TIA)
The main reason for this is that cholesterol tends to build up in the artery wall, causing damage and restricting the flow of blood to your heart, brain and the rest of your body. These effects are often worsened by the presence of other diseases such as diabetes and hypertension. If you have a high cholesterol level or suffer from any of these conditions, or have a close family relative with hypertension, diabetes, kidney disease or who has suffered a heart attack or stroke, it is important that you take the necessary steps to reduce the level of cholesterol in your bloodstream.
Several different factors contribute to high cholesterol. Some of these include diet, lifestyle, age, family history and ethnic background.
Eating an unhealthy diet, lack of exercise or physical activity, being obese or overweight and drinking excessive amounts of alcohol can increase your level of ‘bad cholesterol’. A chemical found in cigarettes is also known to cause ‘bad cholesterol’ to accumulate in the bloodstream, leading to harmful narrowing of the arteries.
A number of underlying medical conditions can also cause high levels of cholesterol. People with high blood pressure and diabetes often have high cholesterol.
Diseases of the kidneys, liver and thyroid may also cause raised levels of cholesterol. Treating these conditions can help reduce your cholesterol.
You are also more likely to develop high cholesterol if you have a close male or female relative (father, mother, brother or sister) aged 65 years or younger who has suffered from heart disease or stroke.
Some people make more cholesterol than others because of a ‘cholesterol-forming’ gene they may have inherited from their parents. ‘Familial’ high cholesterol (or FH for short) is the medical term for genetic high cholesterol that runs in families. This is an inherited condition which can cause high cholesterol even in someone who eats healthily. It is not caused by an unhealthy lifestyle, and treatment for this condition will usually require medication.
If you notice that you (or a member of your family) have a light-coloured ring around the black of your eye or small lumps of fat in the skin around your eyelids (or elsewhere on your body), it may be a sign that you have a high cholesterol level and possibly ‘familial’ high cholesterol.
Cholesterol is tested by means of a simple blood test. You should have your cholesterol level checked regularly if you:
- have been diagnosed with coronary heart disease, stroke or mini-stroke or any disease of the heart and arteries
- are over the age of 40
- have a family history of early heart disease or stroke (under the age of 50)
- have a close family member with a high level of cholesterol
- are overweight
- have high blood pressure, diabetes or a health condition that can increase cholesterol levels, such as thyroid or liver disease
To reduce your cholesterol, the first and most important thing is to maintain a healthy, balanced diet. Keep your diet low in bad fatty food and eat lots of fruit and vegetables instead. Oily fish such as sardines, mackerel, salmon and tuna (when freshly cooked) are full of omega-3 fatty acids, a source of good, ‘friendly fats’ which is able to reduce the level of bad cholesterol in your bloodstream as well as prevent damage to the arteries. You will also need to take regular exercise as well as stop smoking.
If dietary measures and lifestyle changes are not helping to reduce your cholesterol and you continue to be at a high risk of developing heart disease, your doctor may need to prescribe medication to help reduce your cholesterol in addition to treating any underlying conditions or other risk factors (such as diabetes or hypertension) that you may have. The most common group of cholesterol-lowering medication is a class of medicines called ‘statins’.
Statins lower the amount of cholesterol in the bloodstream by reducing the amount of ‘bad cholesterol’ produced by the liver. There are various types of statins and other types of medication which help the body to lower cholesterol. Statins are particularly useful and may be recommended for you if:
• you already have heart disease (such as angina) or have had a ‘heart attack’ or stroke in the past
• you are diabetic (and especially over the age of 40)
• you are healthy but have a high risk of developing heart disease at a later date because of hypertension, diabetes, heart disease or a family history of one or some of these conditions
• you have a high cholesterol level because of a faulty gene you may have inherited from their parents, a condition known as FH or familial high cholesterol
If you are being treated with a statin or other cholesterol-lowering medication, you will also need to make changes to your lifestyle in order to keep your cholesterol at a healthy level. These lifestyle changes will include:
- eating a healthy diet low in harmful fat
- taking regular exercise
- stop smoking if you smoke
- drinking less alcohol
Please speak to your doctor about which statin (or other medication for lowering cholesterol) is most appropriate in your circumstances.