High cholesterol
Cholesterol is a type of fat (lipid)
made by your body. It's essential for good health and is found in every cell in your body.
However, having a high level of certain types of cholesterol in your blood (hypercholesterolaemia) can increase your risk of cardiovascular disease, such as heart disease and stroke.
What cholesterol is and what blood tests for high cholesterol show
About high cholesterol
If you have high cholesterol, it may
affect your heart and blood vessels and increase your risk of developing
cardiovascular disease. High cholesterol causes fatty deposits (known as plaques) to build up inside your blood vessels.
In time, the blood vessels supplying your heart may become so narrow.
They can't deliver enough oxygen to your heart muscle, particularly when you're exerting yourself.
This can cause you to feel chest pain (angina).
If a fatty plaque breaks off, it may cause a blood clot that can block blood flow to your heart (heart attack), or if the same process occurs in your brain it may cause a stroke.
Types of cholesterol
Cholesterol is
transported around your body attached to a protein in your blood. This combination of fat and protein is called a lipoprotein.
There are different types of lipoprotein, depending on how much fat there is in relation to protein.
HDL
A small amount of your body’s
cholesterol is transported as high-density lipoprotein (HDL), which is mostly
protein and not much fat. HDL transports excess cholesterol from your tissues (including the walls of arteries) to your liver for disposal.
As HDL helps prevent cholesterol building up in your blood vessels, you have a reduced risk of heart disease if you have high levels of this type. This is why HDL is often referred to as ‘good’ cholesterol.
LDL
Most of your body's cholesterol is
transported as low-density lipoprotein (LDL). It consists mainly of fat, with
not much protein. LDL transports cholesterol from your liver to your cells.
High levels of LDL increase your risk of cardiovascular disease because LDL causes cholesterol to build up in your blood vessels.
LDL is often called ‘bad’ cholesterol.
Triglycerides
Triglycerides are another type of lipid
that mostly come from fats in your food. Energy from your food that isn’t used immediately is converted into triglycerides and transported to fat cells for storage.
This provides you with an important source of stored energy.
Although most triglycerides are stored as fat, low levels are also found in your blood.
Having a raised level of blood triglycerides together with high LDL can increase your risk of heart disease, particularly if you have diabetes, high blood pressure or you smoke.
Total cholesterol
If you have a high total cholesterol
level, this is a risk factor for future health problems, such as cardiovascular
disease. But the ratio of how much HDL you have compared to total cholesterol
is important too. This is called your total cholesterol (TC) to HDL cholesterol
ratio (TC:HDL). You should aim for a high level of HDL cholesterol and a low
level of LDL (a low TC to HDL ratio).
Symptoms of high cholesterol
You may only find out that you have high
cholesterol if you have a cholesterol test as part of a health check up, or if
you develop symptoms of heart disease. Sometimes, yellow patches (called
xanthomas) may develop around your eyes or elsewhere on your skin – these are
cholesterol deposits and may show that you have high cholesterol.
Complications of high
cholesterol
If you have high cholesterol, it
increases your risk of heart disease and stroke. It may also affect arteries elsewhere in your body such as your legs – this is known as peripheral arterial disease.
Causes of high cholesterol
There
are several factors that may contribute to you having high cholesterol. These include:
·having a
diet high in saturated fat
·a lack of
exercise
·drinking
more than the recommended daily amount of alcohol (this increases the level of
triglycerides in your blood)
·smoking
·age and
gender – your cholesterol levels generally rise with increasing age and can be
affected by your gender
If you're a man younger than 55 you're
more likely to have high cholesterol than a woman. If you’re a woman over 55 and past the menopause, your cholesterol levels are likely to increase.
High cholesterol can sometimes be caused by a condition that runs in your family called familial hypercholesterolaemia (FH).
In the UK, about one in 500 people have this condition. It’s not caused by an unhealthy lifestyle but is passed through families by a faulty gene.
Other
conditions, such as
1. poorly controlled diabetes,
2. certain kidney and
3. liver diseases and
may
also cause your levels of cholesterol or triglycerides to be high. Some medicines such as the oral contraceptive pill, beta-blockers, steroids or thiazides (a type of diuretic) may also affect your blood lipid levels.
Diagnosis of high cholesterol
Your cholesterol level is measured with
a blood test. Usually you will be asked not to eat for 12 hours before the test
so that your food is completely digested and doesn't affect the result. Your
doctor or nurse may take a blood sample using either a needle and syringe, or a
finger prick. You can have your cholesterol tested at your doctor’s surgery, at
hospital, or as part of a health assessment examination.Home-testing kits for cholesterol are also available but may not be very accurate. Speak to your pharmacist about your result if you use a kit.
There is no recommended target level of cholesterol, unless you already have cardiovascular disease or are at high risk.
In these instances, your cholesterol levels should ideally be:
·under
4mmol/l for total cholesterol
·under
2mmol/l for LDL cholesterol
·above
1mmol/l for HDL cholesterol
·under
1.7mmol/l for triglycerides
The levels of cholesterol in your blood can
vary from day to day, so your doctor may take a series of different readings
before recommending any treatment.
Who should have a cholesterol test?
If you’re at high risk of cardiovascular
disease or you have a family history of high cholesterol, you should have your
cholesterol levels checked. Speak to your doctor about how often it should be tested.
Your doctor should check your cholesterol levels every year if you have cardiovascular disease.
Treatment of high cholesterol
If
you have high cholesterol, there are two ways in which you can reduce it. The first is with lifestyle changes, which include
1. changing your diet,
2. managing your weight and
3. exercising.
The second is to combine lifestyle changes with
cholesterol-lowering medicines.
Self-help
By eating healthily, you can reduce your
cholesterol levels. Your diet should be low in saturated fats in particular,
and low in fat overall. Biscuits, cakes, pastries, red meat, hard cheese and
butter all tend to be high in saturated fats, so it’s good to cut down on these
foods.Some foods such as eggs, prawns and offal (for example, liver and kidneys) contain cholesterol.
This type of cholesterol is known as dietary cholesterol and it has a much lower effect on blood cholesterol than saturated fat in your diet. You may need to cut down on these foods if your doctor advises you to.
It's also important to include plenty of fibre in your diet, especially soluble fibre, which helps to lower cholesterol.
There is soluble fibre in fruits and vegetables, beans and oats.
Aim to eat at least five portions of fruit and vegetables each day.
Eating foods containing substances called plant sterols or stanols, contained in some yoghurts or spreads, may help to lower high cholesterol, but they are not a substitute for a healthy diet.
If you're overweight, losing your excess weight can reduce your LDL levels and increase your HDL levels.
Increasing your physical activity may enhance the cholesterol-lowering effects of your diet.
As high cholesterol can increase your risk of heart disease, you should reduce any additional risk of developing it, such as by stopping smoking.
Medicines
Medicines are generally recommended
either if you already have cardiovascular disease or if your risk of getting it
is more than 20 percent over 10 years. The main group of medicines for lowering cholesterol are called statins.
Statins available in the UK include
1. simvastatin,
2. atorvastatin,
3. fluvastatin,
4. pravastatin, and
5. rosuvastatin.
These medicines work by reducing the production of cholesterol in your
liver, but can have side-effects such as indigestion and muscle pains.Other types of medicines used to reduce cholesterol include
1. fibrates,
2. nicotinic acid and
3. cholesterol-absorption
4. inhibitors such as ezetimibe
(Ezetrol),
but
these are generally less effective than statins or have more side-effects. If
you have very high cholesterol, your GP may prescribe ezetimibe with statins.
Prevention of high cholesterol
You may be able to prevent high
cholesterol by keeping to a healthy weight and eating a diet that is low in
saturated fat. Try to include at least two portions of fish per week in your diet, of which at least one should be an oily fish such as mackerel or salmon.
Try to take regular exercise, avoid smoking and stick to recommended limits of alcohol.
If you don’t have high cholesterol, consuming products containing plant sterols or stanols, such as yogurts or spreads, is not recommended (and they are not suitable for women who are pregnant or breastfeeding).
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