High cholesterol: symptoms, causes, diet and treatment

High cholesterol does not usually cause symptoms, the NHS says. You can only find out if you have it from a blood test. The BHF calls it a hidden risk factor, meaning you can have it without knowing, which is why it is important to get your levels checked.

The BHF says that if you have familial hypercholesterolaemia (FH), an inherited cause, you may have visible signs of high cholesterol. Neither the NHS nor the BHF lists any everyday symptom of high cholesterol. The problems that appear later are those of the blocked or narrowed arteries it contributes to, which the BHF links with heart attack and stroke.

The BHF describes cholesterol as a fatty substance in your blood that is produced naturally in your liver. Some cholesterol is important because the cells in your body use it to keep them healthy. HEART UK says there is cholesterol in every cell, and that it is used to make vitamin D, steroid hormones and bile.

The trouble starts when there is too much. The BHF says too much cholesterol in the blood can narrow your arteries and cause fatty material to build up (atherosclerosis), which can increase your risk of a heart attack or stroke. You may also hear it called hypercholesterolaemia or hyperlipidaemia.

The BHF explains that cholesterol is carried around the body by proteins; together they are called lipoproteins. High-density lipoprotein (HDL), or "good" cholesterol, takes cholesterol you do not need back to the liver, which breaks it down. Non-HDL, or "bad" cholesterol, mostly made up of LDL cholesterol, takes cholesterol from your liver to cells, and too much can get stuck to the walls of your arteries.

Triglycerides are another blood fat. The BHF says too much in the blood can narrow the arteries, and that excess weight, food high in saturated fat and sugar, and too much alcohol can raise them. HEART UK says a high triglyceride level should be investigated by your GP.

The NHS says high cholesterol can be caused by eating fatty food, not exercising enough, being overweight, smoking and drinking alcohol. You are more likely to get it if you are over 50, a man, have been through the menopause, or are of South Asian or sub-Saharan African origin, and it can run in families.

The BHF says anyone can get high cholesterol, that some causes can be influenced and others cannot, and lists the following.

• Lifestyle: eating too much saturated fat, not being active enough, smoking, and living with excess weight, especially round the middle.

• Age: getting older can increase cholesterol levels.

• Sex and menopause: being born male increases risk from a younger age, and risk goes up during and after the menopause.

• Family history: a family member who had a heart attack or stroke before 60 caused by a blocked or narrowed blood vessel.

• Genetics: some causes pass down through families, including familial hypercholesterolaemia (FH) and high Lp(a).

• Other conditions: kidney disease, liver disease, type 2 diabetes, an underactive thyroid and growth hormone deficiency.

The NHS says to cut down on fatty food, especially food containing saturated fat, while you can still have foods that contain the healthier unsaturated fat. It suggests checking food labels to see what type of fat is in them.

The BHF says that some foods naturally contain cholesterol, such as eggs, liver, kidney and shellfish like prawns, but for most people dietary cholesterol does not have much effect on cholesterol levels, and these foods can be eaten as part of a healthy diet.

The NHS says to aim for at least 150 minutes (2.5 hours) of moderate intensity exercise or 75 minutes of vigorous intensity activity a week, and suggests walking fast enough that your heart beats faster, swimming or cycling.

Smoking can raise your cholesterol and make you more likely to have serious problems such as heart attacks, strokes and cancer. The NHS says your GP and NHS stop smoking services can help. For alcohol, it suggests avoiding drinking more than 14 units a week on a regular basis, spreading it over 3 or more days, and having several drink-free days each week.

The BHF says your cholesterol is measured with a blood test, sometimes called a lipid profile because it looks at different fats in your blood. You can get it checked at your GP practice, or in some pharmacies using a finger-prick test. Adults in England should be offered a free NHS health check when they turn 40, and the rest of the UK may have similar schemes.

The BHF says a blood test will measure HDL, non-HDL, the cholesterol ratio, triglycerides and total cholesterol, and that your GP may also ask for LDL. It says that if you have had a heart attack or stroke your recommended levels may be lower, so ask your doctor what your own target should be. If you have high cholesterol, your GP should invite you for a blood test every year to check your levels and how you are getting on with any medicines or lifestyle changes.

The BHF says your doctor may recommend medicine to help lower your cholesterol, which can also help reduce your risk of a heart attack or stroke. Statins are the most common medicine used, and sometimes other medicines are prescribed, usually by a specialist. You will usually need to make healthy lifestyle choices as well as taking medicine.

The NHS says some people need to take medicine in addition to eating healthily and getting more exercise. Whether you need a statin depends on your overall risk of heart disease, which your GP can estimate with you; do not start or stop a statin without talking to them.

See a GP or pharmacist for a cholesterol check if you have not had one, particularly if you are over 40, have a family history of early heart attack or stroke, or have a condition that raises cholesterol. HEART UK and the NHS both note that inherited high cholesterol (familial hypercholesterolaemia) starts at a young age and runs in families.

Because high cholesterol itself causes no symptoms, new chest pain, breathlessness or sudden weakness of the face, arm or leg need emergency help through 999 regardless of your cholesterol result.

On the NHS, cholesterol can be checked at your GP practice or as part of an NHS health check, and statins and annual reviews are managed by your GP. Specialists such as lipid clinics usually see people with inherited high cholesterol or very high levels that do not respond.

Private blood tests and health checks are widely available and can measure cholesterol, but results should be shared with your GP so that your overall heart risk can be assessed and treatment decisions made.