Cholesterol

What is cholesterol and why does high cholesterol matter? Find out what it is, how it affects your heart and the steps you can take to lower it.

What is cholesterol?

Cholesterol (matū ngako) is a waxy fat-like substance in your blood. Your liver makes most of it and you also get some from the food you eat. 

Cholesterol isn’t always bad. Your body needs some to build cells, make hormones and help with digestion. But if the amount of cholesterol in your blood gets too high, it can cause a heart attack or stroke. 

Cholesterol and triglycerides

Cholesterol can’t move through your blood on its own, so your body packs it into lipoproteins. These are tiny packages made of fat and protein. Lipoproteins act like tiny couriers, moving cholesterol through your bloodstream.  

The two main types are:       

• low-density lipoprotein (LDL) 
• high-density lipoprotein (HDL) 

Because these lipoproteins carry cholesterol, people often call them LDL cholesterol and HDL cholesterol.

LDL cholesterol

LDL carries cholesterol from your liver to your cells. It’s called the ‘bad cholesterol’ because if you have too much, it builds up in the walls of your arteries (the blood vessels that carry blood and oxygen around your body). This increases your risk of heart attack or stroke.

HDL cholesterol

HDL is the ‘good’ cholesterol. It works like a cleaner, carrying extra LDL cholesterol away from your arteries and back to your liver, where it’s broken down. Healthy levels of HDL are useful, but they don’t reduce the risk from high LDL cholesterol.

Triglycerides

Triglycerides are the most common type of fat in your blood. Your body makes them from extra energy in food and drink. Your levels rise for a short time after eating but, if you often consume more energy than your body needs, your levels can stay high.    

High triglycerides increase your risk of heart attack, stroke and acute pancreatitis.

Cholesterol tests

A blood test is the only way to check your cholesterol levels. It’s often called a ‘lipid profile’ or ‘lipid test’. Lipid is another word for fat, so this test measures fats in your blood, including cholesterol and triglycerides.

Your test results will show your:  

• HDL (good) cholesterol 
• LDL (bad) cholesterol
• triglycerides
• total cholesterol – all the cholesterol in your blood  
• cholesterol ratio – compares your total cholesterol to your HDL. A lower ratio means a lower risk of heart disease 
• non-HDL cholesterol – all the cholesterol in your blood that’s not HDL. A higher level means a higher risk of heart disease.

Where can I get a cholesterol test?

Most people are referred by their GP or nurse to a blood testing centre or laboratory. Some tests may be able to be done at your medical centre. 

Some pharmacies offer a finger-prick test. If the reading is high, you’ll need a follow-up appointment with your doctor or nurse.

When should I get my cholesterol checked?

If you haven’t had a cholesterol test before, talk to your healthcare professional about when you should have one. Generally, people aged 45 and above should have their cholesterol checked even if they have no known risk factors. After this age, they should be tested on a regular basis.

Cholesterol tests are a routine part of a heart risk check. You may also need regular tests if you:   

• take cholesterol-lowering medicines (statins) 
• have a family history of high cholesterol
• have diabetes, kidney or liver disease, or an underactive thyroid     
• are at higher risk of heart attack or stroke.

What’s a healthy cholesterol level?

There’s no single ‘normal’ level for everyone. Your ideal cholesterol level depends on your overall risk of heart attack or stroke. To work this out, your healthcare provider may do a heart risk check, also called a heart check. 

Cholesterol is measured in millimoles per litre (mmol/L). 

People at very high risk should aim to have an LDL cholesterol level of 1.4 mmol/L or less. 

For adults who aren’t at high risk, the focus is on lowering LDL as much as possible and keeping HDL and triglycerides in a healthy range.

Guide for people with diagnosed high cholesterol, heart disease, diabetes or at high risk of heart disease

Guide for people without major heart disease risk factors

What is high cholesterol?

High cholesterol is when there’s too much LDL cholesterol and/or not enough HDL cholesterol in your blood. You may also have high triglycerides. 

High cholesterol speeds up the fatty build up in your arteries and increases your risk of heart attack or stroke . 

Other terms for high cholesterol you might hear:  

• hyperlipidaemia
• hypercholesterolaemia
• dyslipidaemia
• abnormal lipids.

Is high cholesterol bad for you?

When you have too much LDL cholesterol, it can build up in the walls of your arteries. This forms plaque, which is a mix of fat, cholesterol, calcium and other substances. Over time, plaque causes the arteries to narrow, making it harder for blood to flow through. This process is called atherosclerosis. 

If a plaque breaks open, a blood clot can form. This can cause a heart attack or stroke.

What are the symptoms of high cholesterol?

High cholesterol does not cause symptoms. The only way to know is with a blood test.

What causes high cholesterol?

High cholesterol has many causes. Some of these can be changed and others can’t.   

Risk factors you can change or manage: 

• eating foods high in saturated fat
• having a lot of added sugar and/or refined carbohydrates, often found in highly processed foods   
• drinking more alcohol than recommended
• not being active enough 
• excess weight, especially around your middle  
• smoking
• diabetes
• kidney disease
• other medical conditions such as liver disease, or an underactive thyroid.

Making changes to your daily habits can lower your cholesterol and support heart health. Some people may also need cholesterol-lowering medicine.    

Risk factors you can’t change: 

• family history
• age
• sex assigned at birth (male or female) 
• inherited conditions.

Inherited high cholesterol

Some people have high cholesterol because of a genetic condition passed down through their family. These conditions include: 

• familial combined hyperlipidaemia (high cholesterol and triglycerides)
• familial hypercholesterolaemia (very high LDL)
• familial hypertriglyceridaemia (very high triglycerides).

These conditions can affect people at a young age. If a parent or sibling has one of these, ask your doctor about checking your cholesterol.

Other conditions linked to high cholesterol

High cholesterol is linked to: 

• coronary artery disease, which can cause angina or a heart attack 
• peripheral artery disease, which reduces blood flow to the legs
• stroke.

These conditions are linked to plaque build-up in the arteries. Lowering your cholesterol reduces your risk.

How can I lower cholesterol?

There are several ways to lower your cholesterol. For some people, lifestyle changes are enough. Others may need medication as well as lifestyle changes. 

Cholesterol-lowering medicine

Statins are the most common type of cholesterol-lowering medicine. They work by slowing down how much cholesterol your liver makes. This lowers your LDL cholesterol. 

If you’re prescribed a statin, take it as directed. It’s one of the most effective ways of lowering cholesterol. Most people can take statins without problems. Side effects can occur, but they’re usually mild and often improve with time. 

Read more about statins. 

In addition to statins there are cholesterol-absorbing inhibitor drugs. Ezetimibe is one that is available in New Zealand and is used to treat high cholesterol. It works by reducing the amount of cholesterol absorbed from food. It can be given with statins or as an alternative to statins if statins are not working or are not being well tolerated.

Maintain a healthy weight

Maintaining a healthy weight can keep your LDL cholesterol lower and reduce strain on your heart. 

Making changes to what you eat and how much you move makes a difference over time. Starting with small, realistic steps can help you make the change.

If you’re finding it hard to lose weight, talk to your doctor. They can discuss other options with you, including weight loss medicines.

Read more about managing your weight for a healthy heart. 

Eat heart-healthy food

What you eat can make a big difference to your cholesterol levels.  

Focus on: 

• fruits and vegetables
• whole grains
• nuts and seeds
• legumes
• healthy fats e.g. olive oil, canola oil and oil-based spreads. 

Cut back on:  

• butter and high-fat dairy foods (e.g. cream and high fat cheeses)
• fatty and processed meats
• takeaway foods and baked goods e.g. pies and cakes
• added sugar and salt. 

Try our 7-day meal plan to lower cholesterol

Move more

Sitting less and being more active are great ways to reduce high cholesterol. This doesn’t mean you need to join a gym or take up running – it just means moving your body more throughout the day. Each week, aim to do 150 minutes of moderate activity.

You could try:

• parking 10 minutes from work or getting off the bus one stop early
• walking the kids to school
• household jobs like vacuuming or mopping
• taking the stairs instead of the lift 
• a short home workout with a free online video
• playing with children or pets outdoors. 

Read more about the benefits of exercise. 

Drink less alcohol

Drinking too much alcohol, particularly heavy drinking (binge drinking), can raise your LDL cholesterol and triglycerides. 

Our latest advice is that no alcohol is best for your heart. If you don’t drink alcohol, don’t start. If you do drink alcohol – it’s better to drink less.

Read more about alcohol and the heart. 

Quit smoking

Quitting smoking is a great way to lower cholesterol. Smoking damages the lining of your arteries. This damage makes it easier for LDL cholesterol to build up. Smoking also lowers the amount of good cholesterol in your blood.  

Find out how to quit smoking. 

Can you lower cholesterol naturally?

Some people think about using natural therapies to lower cholesterol. These may interact with any medicines you’re taking, which can be dangerous. They can also make your medicine less effective. Check with your doctor, nurse or pharmacist before taking any:  

• supplements
• vitamins
• natural remedies
• complementary therapies.  

7 foods that may lower your cholesterol

7-day meal plan to help lower cholesterol