About high cholesterol

An unhealthy diet, lack of exercise, being overweight and raised cholesterol are all bad news for your heart health.  So whether you've just been diagnosed with high cholesterol, or you've been living with the condition for some time, you're probably concerned about how it's going to affect you in future. What's more, it's likely that your diagnosis of raised cholesterol came out of the blue so you haven't been prepared for the lifestyle changes you've been advised to make. At first, leading a healthy lifestyle can seem a daunting challenge if you're not used to it.

But managing your cholesterol doesn't necessarily mean big changes to your life, and there's plenty of help available. Because high cholesterol is extremely common, it's something doctors are very used to dealing with and there's a range of treatment options open to you. By taking on board the advice, and medication if you need it, you can limit the impact of your high cholesterol on your life.

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How much do you know already?

What is cholesterol?

Cholesterol is a type of lipid, a fatty substance found throughout the body. About 25% of our cholesterol comes from the fatty foods we eat – the other 75% is made by the liver.

1. Why do we need cholesterol?

   We need cholesterol in the body to: Form an essential part of all the cells in the body, the cell membrane; Make hormones; Insulate nerve fibres; Make bile, used to digest fats You may hear the terms hyperlipidaemia or hypercholesterolemia – these mean having too many lipids, or specifically too much cholesterol, in your body. Some people naturally make too much cholesterol. However, high levels of cholesterol are also linked to things we do in everyday life, such as eating a diet high in saturated fat, drinking too much alcohol, not taking enough exercise. Being overweight is also linked to raised cholesterol. If your cholesterol levels become too high, they can cause fatty build-ups of plaque, forming lumps in the walls of your arteries – the blood vessels that carry blood from your heart around your body. These plaques can clog up the arteries, narrowing and sometimes eventually blocking the blood flow. If the blockage is in a blood vessel going to a part of the heart muscle it can cause a heart attack; if the blockage is in an artery supplying the brain it can lead to a stroke. If a fatty lump breaks away from the artery wall, a blood clot may form which could also lead to a heart attack or a stroke. This process of clogging up the arteries is called atherosclerosis. Some people with atherosclerosis get chest pain during activity or even at rest – this is angina, and it happens because the narrowing of the arteries means there isn’t enough blood getting through to the heart. See Complications for more about the effects of high cholesterol. High cholesterol is especially dangerous if you have additional factors that put you at risk of a heart attack or stroke, such as high blood pressure. If you’ve already had a heart attack or stroke, high cholesterol increases the danger of having another one.

2. What does being a ‘risk factor’ for heart disease mean?

   High cholesterol is one of many risk factors for heart disease and stroke. A risk factor is a condition or behaviour that increases your chances of getting a disease. It can also be a warning sign. If your cholesterol is high, it's important to talk to your doctor about lowering it.

3. What other risk factors are there for heart disease?

   Many of the other risk factors for heart disease or stroke are linked to high cholesterol, so if you have high cholesterol you may well have other risks. Risk factors you can't control Your age; Family history of early heart disease; Risk factors you can try to manage High LDL (low-density lipoprotein, or "bad") cholesterol; Low HDL (high-density lipoprotein, or "good") cholesterol; High triglycerides (a type of fat found in your blood); High blood pressure; Obesity; Diabetes; Smoking For more on risk factors for cholesterol, see Who gets high cholesterol? (link T2 Who gets high cholesterol)

Types of cholesterol

Not all cholesterol is bad for you. There are two types that travel around in your blood:

1. ‘Bad cholesterol’ – LDL

   This is called low density lipoprotein (LDL). You can think of this as a delivery lorry. It carries cholesterol from the liver where it’s made to the cells where it’s needed. But if there’s more LDL than your cells need, it stacks up in the blood – your blood vessels become the ‘lorry park’. The cholesterol builds up in the artery walls, narrowing the arteries and creating a risk of heart attack or stroke. This is why treatment aims to reduce your LDL.

2. ‘Good cholesterol’ – HDL

   This is high density lipoprotein (HDL). It’s like a rubbish-collecting lorry. It can sweep up the excess cholesterol and carry it away from our arteries and back to the liver, where it is broken down and recycled. So higher levels of HDL are better. It’s the balance of good and bad cholesterol in our blood that is important in keeping healthy and protecting against damage. When you have a blood test for cholesterol, it will measure individual levels of both HDL and LDL, as well as your total blood cholesterol.

How much is too much?

Cholesterol levels are measured in units called millimoles per litre of blood (mmol/L).

Doctors are most worried when someone has high levels of LDL cholesterol and low levels of HDL cholesterol. They now say that for people who are at risk of developing cardiovascular disease, total cholesterol levels should be less than 4mmol/L and LDL should be less than 2mmol/L. (4) It's especially important to reach the target if you already have cardiovascular disease.