High cholesterol

Expert reviewer, Dr Adrian Raby, General Practitioner and Clinical Lecturer
Next review due January 2022

Cholesterol is a type of fat (lipid) made by your body and found in some foods.

Cholesterol is essential for good health and is found in every cell in your body. But having a high level of cholesterol in your blood can harm your health.

Doctor and patient are talking

About high cholesterol

With a high level of certain types of cholesterol you increase your risk of cardiovascular disease, such as heart disease and stroke. This is because it can cause fatty deposits (known as plaques) to build up inside your arteries. Over time, these can make your arteries narrower and narrower, restricting the flow of blood to important organs such as your heart. Other parts of your body may also be affected, including your limbs (peripheral arterial disease).

More importantly though, if the surface of one of the plaques in your arteries breaks or the plaque bursts, a blood clot may form. This can completely block the blood supply to part of your heart, causing a heart attack. Or it might block the blood supply to your brain, which would cause a stroke.

Types of cholesterol

Cholesterol is carried around your body by a protein in your blood. This combination of fat and protein is called a lipoprotein. There are different types of lipoprotein, and they may be harmful or beneficial to your health. This is why you may have heard about ‘good’ cholesterol and ‘bad’ cholesterol.

Good cholesterol (HDL)

High-density lipoprotein (HDL) helps to get rid of excess cholesterol by carrying it from your tissues to your liver. Your liver then breaks down the cholesterol so your body can get rid of it. HDL helps to reduce your risk of heart disease and stroke so is often referred to as ‘good’ cholesterol.

Bad cholesterol (LDL, non-HDL)

Low-density lipoprotein (LDL) carries cholesterol from your liver to the cells around your body where it’s needed. But if the level of LDL in your blood is too high, it can form fatty deposits in your arteries. This increases your risk of heart disease and stroke, so LDL is often called ‘bad’ cholesterol.

However, although LDL is the main bad cholesterol, there are some other types which can be harmful. That’s why doctors now often talk about ‘non-HDL cholesterol’ as the bad cholesterol. Non-HDL cholesterol is ‘all the cholesterol in your blood which isn’t good cholesterol’.

Symptoms of high cholesterol

High cholesterol doesn’t cause any symptoms by itself. But if you have it, it can lead to serious problems affecting your heart and circulation, such as heart attack and stroke. You may start to develop symptoms of heart disease such as angina (chest pain that comes on with exertion and is relieved by rest). Or you may have pain in your calves on exercise which goes away when resting.

Contact your GP if you have symptoms you’re concerned about, and contact them as soon as possible if you have angina chest pain.

Diagnosis of high cholesterol

Measuring cholesterol

Your cholesterol level can be measured with a simple blood test. Depending on the type of test you have, you may be asked not to eat or drink anything except water for eight hours beforehand. It’s important to follow any instructions you’re given.

The test will measure the various types of cholesterol in your blood (see our section above on types of cholesterol). It may also measure another type of fat called triglycerides. A high level of triglycerides is also a risk factor for heart disease and stroke.

Below is a general guide to cholesterol levels in healthy adults.

Total cholesterol (TC) - 5mmol/L or below

Non-HDL (all ‘bad’) cholesterol - 4mmol/L or below

LDL (main ‘bad’) cholesterol - 3mmol/L or below

HDL (‘good’) cholesterol - 1mmol/L or above

Cholesterol ratio TC/HDL - 4mmol/L or below

Triglycerides - 2mmol/L or below

However, it’s important to discuss with your doctor or nurse what your test results mean for you individually. They’ll take into account other factors, including your age, sex, body mass index (BMI), blood pressure, family history and whether you smoke. They’ll also consider other health conditions you may have or medicines you’re taking.

The levels of cholesterol in your blood can vary from day to day. So your doctor may want to repeat the test before recommending any treatment.

Who should have a cholesterol test?

When you reach 40, your GP may offer you a cholesterol test. This will be part of a health check to work out your risk of developing heart disease and stroke.

Your GP may also offer you a cholesterol test if you:

  • have a high blood pressure
  • have diabetes
  • are overweight or obese
  • having a family history of high cholesterol (known as familial hypercholesterolaemia)
  • might have kidney disease
  • are unable to get or maintain an erection (erectile dysfunction)

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Treatment of high cholesterol

If you’re classed at being at high risk of having heart disease or stroke, your doctor will recommend you take steps to lower your cholesterol.


To begin with, your GP will recommend some lifestyle changes you can make in order to reduce your risk of heart attack and stroke. These may include:

Some foods have quite a lot of cholesterol in them. These include eggs, shellfish and offal. You might think you always need to avoid these if you have high cholesterol. However, experts think that it’s much more important to reduce the amount of saturated fats you eat. You should cut down on the high cholesterol foods if your doctor or dietitian advises you to.


The main group of medicines for lowering cholesterol are called statins. Your GP may recommend you take a statin if changes to your lifestyle haven’t reduced your cholesterol level enough. Or they may recommend them from the start if your risk of problems like heart disease is high.

It’s your choice whether or not you take statins. To help you to make a decision, your doctor will discuss their risks and benefits with you before you start any treatment.

Your GP will usually ask to check your cholesterol level again around three months after you’ve started treatment, to see how well it’s working. If you don’t get on with your treatment, or it’s not working very well, your GP may suggest changing the dose or trying another statin. They may recommend alternative medicines or seek specialist advice if you find you can’t tolerate statins even after trying three different kinds.

Causes of high cholesterol

High cholesterol is often caused by a number of factors, which all act to increase your cholesterol level. As well as your genetic makeup, these may include:

  • having a diet high in saturated fat. See our FAQ on fats below for more information
  • not doing much exercise
  • being overweight or obese
  • drinking too much alcohol

Sometimes, high cholesterol can be caused by a condition that runs in your family called familial hypercholesterolaemia. This means you may have a very high cholesterol level, even if you have a healthy lifestyle.

Other conditions, such as poorly controlled diabetes, certain kidney and liver diseases and an underactive thyroid (hypothyroidism) may also cause high cholesterol. Some medicines can also raise your cholesterol, such as oral contraceptives, steroids and thiazide diuretics (a type of medicine to reduce your water level).

Prevention of high cholesterol

In most cases, high cholesterol is preventable through changes to your lifestyle and diet. See our section on self-help above which has links to lots of helpful information on making these healthy changes. You can also find some tips on maintaining healthy cholesterol levels.

Frequently asked questions

  • It’s important to have some fats in your diet. But eating too much of the wrong types of fat can increase your cholesterol levels.

    Eating a lot of saturated fat increases how much cholesterol your liver produces, and slows down how quickly it’s removed from your body. Foods containing saturated fat include cakes and biscuits, pastry, meat products and full fat dairy products (milk, cheese, cream).

    To help keep to a healthy cholesterol level, cut down on saturated fat by using low-fat options. And where you can, try to have unsaturated fats instead. Unsaturated fats include olive and sunflower oils, nuts, seeds and oily fish.

    Find more tips to help you get the right amounts of fat in your diet.

  • Plant sterols and stanols are often added to certain food products, including some spreads, yoghurts and mini-drinks. Regularly consuming these can help to reduce your level of LDL (‘bad’) cholesterol. However, no one knows yet whether taking them also reduces your risk of heart attack and stroke.

    It’s your choice whether or not to try sterols and stanols. Medical guidelines currently do not recommend them for people who have been advised to reduce their risk of heart disease and stroke. If you do decide to try taking them, you should still aim to make any lifestyle changes or take any medicines that your doctor advises. See our section on treatment of high cholesterol above for more information.

    You shouldn’t take products containing sterols and stanols if you’re pregnant or breastfeeding, and they’re not suitable for children under the age of five.

  • A few years ago, some researchers looked at cholesterol levels in couples who were having problems having a baby. They found that it took longer for the woman to become pregnant when she, or both she and her partner, had a high cholesterol level.

    No one knows for sure yet whether having a high cholesterol level makes it harder to get pregnant, or whether lowering your cholesterol might help you get pregnant. But what we do know is that it’s good to be as healthy as possible when trying to get pregnant. See our treatment section above for tips on changes to your lifestyle that will help.

    You shouldn’t take statins during pregnancy. If you’re taking statins already, these should be stopped three months before you start trying to get pregnant. If you’re on statins and you’re planning to get pregnant, or might get pregnant, discuss this with your GP.

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Related information

Tools and calculators

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  • Reviewed by Dr Kristina Routh, Freelance Health Editor, Bupa Health Content Team, January 2019
    Expert reviewer, Dr Adrian Raby, General Practitioner and Clinical Lecturer
    Next review due January 2022