High cholesterol

Expert reviewer, Melanie Hill, Bupa Clinics GP
Next review due June 2024

Cholesterol is a type of fat that’s made by your body and is found in some foods. You have cholesterol in every cell of your body – it’s vital for good health. But although your body needs cholesterol to work properly, too much of some types of cholesterol can harm your health.

About high cholesterol

Cholesterol has an important role in the way your body works. Your body needs cholesterol to:

make hormones and vitamin D
make bile acids, which help your gut to digest the food you eat
construct the outer layer (membrane) of your body’s cells

But if you have a high level of certain types of cholesterol, you increase your risk of cardiovascular disease – for example, heart disease and stroke. This is because one type of cholesterol can cause fatty deposits (known as plaques) to build up inside your arteries. Over time, these can make your arteries narrower and narrower, which restricts the flow of blood to organs such as your heart. This can affect other parts of your body too, including your arms and legs (peripheral arterial disease).

There’s plenty you can do to manage cholesterol and keep it at healthy levels.

Types of cholesterol

A protein in your blood carries cholesterol around your body. 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

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. Your liver uses it to make bile that helps with digestion, and some of this is removed from the body as a waste product in your poo.

Having lots of HDL in your blood is a good thing – it helps to prevent heart disease, so it’s called ‘good’ cholesterol.

Bad cholesterol

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 cause fatty deposits to build up in your blood vessels (atherosclerosis). This can increase your risk of heart disease and stroke, so LDL is called ‘bad’ cholesterol.

However, although LDL is the main ‘bad’ cholesterol, there are some other types which can also 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’.

Causes of high cholesterol

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

a diet that’s high in saturated fat or trans fats
not doing much exercise
being overweight or obese
drinking too much alcohol

Sometimes, high cholesterol is 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 health conditions may cause high cholesterol. These include:

poorly controlled diabetes
certain kidney and liver diseases
an underactive thyroid (hypothyroidism)

Some medicines can raise your cholesterol. These include:

oral contraceptives
steroids
beta blockers

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 GP can measure your cholesterol levels with a blood test. The test measures the different types of cholesterol and the total amount of cholesterol in your blood. 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.

Your GP surgery will tell you how to prepare for the test. They may ask you not to eat anything for about 12 hours before having the blood test. Always follow any instructions your doctor or GP surgery gives you.

It’s important for everyone to aim for healthy blood cholesterol levels. This means a:

low total cholesterol
low level of LDL cholesterol
high level of HDL cholesterol

Here 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: 2.3mmol/L or below

These figures only give a general idea of normal cholesterol levels. 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, such as your age, sex, body mass index (BMI), blood pressure, family history and if you smoke. They’ll also consider other health conditions you may have or medicines that you take.

Levels of cholesterol in your blood can vary from day to day. So, your doctor may want to repeat the test before they recommend 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 that you have every five years 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
have a family history of high cholesterol (known as familial hypercholesterolaemia)
have heart disease
smoke
are unable to get or maintain an erection (erectile dysfunction)

Self-help for high cholesterol

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

Stop smoking. If you smoke, you have less good cholesterol in your bloodstream. If you quit, you can help to keep your cholesterol levels healthy and improve your health.
There isn’t a high cholesterol diet as such but do take steps to reduce fat in your diet, particularly saturated and trans fats. Try to replace saturated and trans fats with unsaturated fats where you can.
Make other healthy changes to your diet – eat more fibre and more wholegrain carbohydrate foods because this can help to lower LDL cholesterol. And eat more fruit and vegetables, oats, beans and pulses (for example, lentils and soya).
Exercise more. If you’re physically active, it can help to keep your cholesterol levels healthy.
Lose any excess weight to help to reduce your LDL cholesterol level. Aim to be a healthy weight and you’ll feel the benefit.
Don’t drink more than the recommended alcohol limits.

Some foods have quite a lot of cholesterol in them. These include eggs, shellfish and offal. You might think you shouldn’t eat these if you have high cholesterol. But to lower cholesterol with diet, experts think that it’s much more important to reduce the amount of saturated fats you eat, and to cut out trans fats. If you eat a lot of saturated and trans fat, it increases how much cholesterol your liver produces, and slows down how quickly it’s removed from your body. But do cut down on the high cholesterol foods if your doctor or dietitian advises you to.

If you add plant stanols and sterols to your diet, it may help keep your cholesterol levels healthy. These are found in fruits, vegetables, nuts and wholegrains. They’re also added to some food and drink, such as mini-drinks, yogurts and spreads.

Treatment of high cholesterol

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

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 you change the dose or try a different statin. They may recommend alternative medicines or seek specialist advice if you find you can’t tolerate statins even after trying three different kinds.

You shouldn’t take statins if you’re pregnant. And if you plan to get pregnant, stop taking statins three months before you start trying. Ask your GP for more information.

Prevention of high cholesterol

High cholesterol is often preventable if you make changes to your lifestyle and diet. See our self-help section for information on how to make these healthy changes. You can also find some tips on maintaining healthy cholesterol levels.

The following video also explains how to keep your heart healthy.

A healthy heart is central to your overall health.

Your heart health is heavily influenced by your lifestyle, but largely these effects go under the radar.

Let's take you inside your heart so we can better understand how your lifestyle choices affect you.

Your heart is a muscle, and like any other muscle, it needs exercise to work properly.

During exercise your muscles work harder and need more oxygen, meaning your heart must beat faster to meet the demands of the body.

The more you work your heart, the bigger and stronger it gets.

Being active can reduce your risk of heart disease by as much as 35 percent, and any exercise is better than no exercise, so go at your own pace.

Smokers are twice as likely to develop a serious heart problem. With every cigarette you breathe in around 5000 chemicals, many of which are harmful to your health.

These chemicals cause the blood to thicken and form clots inside the veins and arteries, which can lead to coronary heart disease.

But these impacts are largely reversible.

Within a year of quitting smoking, you would have halved your risk of a heart attack or stroke.

Eating a healthy, balanced diet can counteract high blood pressure and cholesterol levels, both of which can harm your heart health.

Eating too much saturated fat is linked to increased levels of bad cholesterol in your blood.

This can cause fatty deposits to build up in your arteries, which over time can lead to heart disease or even a heart attack.

When you sleep, your heart gets a rest and your heart rate and blood pressure go down.

Not getting enough sleep regularly can lead to high blood pressure, diabetes and weight gain.

Everyone needs a different amount of sleep to feel rested, but in general, the average adult should be aiming for seven to nine hours each night.

By staying hydrated, you are helping your heart do its job.

It can pump blood more easily and get oxygen to your muscles more efficiently.

Most adults need around two to two and a half litres of fluid every day, with most of that coming from drinks and some from the food we eat.

Stress and unhealthy habits associated with it play a big part in your overall well being.

There's plenty of ways to manage your stress levels, explore your options, and find a solution that fits you, your lifestyle, work and personality.

All these factors play a huge part in helping us lead a healthy lifestyle, all of which keeps your heart, and yourself, happy and healthy.