So you’ve had a blood test and found out you have high cholesterol. Don’t panic, half of New Zealanders actually have ‘high cholesterol’ so you’re not alone. But that doesn’t mean you can sit back and relax either, as high blood cholesterol is a major health concern in New Zealand. It’s important to get on top of your cholesterol as you get older and particularly if you’re already at risk of heart disease.
What is cholesterol?
Cholesterol is an essential type of fat that is carried in the blood. We need a small amount of blood cholesterol because the body uses it to build cell membranes, make hormones, vitamin D, and bile acids that help us digest fat. Cholesterol also helps us to form memories and is vital for neurological function.
So that’s the plus side of cholesterol. The bad news is that too much cholesterol in the blood can damage our arteries and lead to heart disease.
Cholesterol is a white, waxy substance made in the liver and also by most cells in the body. It is carried around in the blood by little ‘couriers’ called lipoproteins to the target organs that need it:
- The Good: high-density lipoprotein (HDL) cholesterol – these lipoproteins carry the ‘good’ cholesterol that helps remove excess cholesterol out of the cells, including the arteries.
- The Bad: low-density lipoprotein (LDL) cholesterol – these lipoproteins carry most of the cholesterol that is delivered to cells. LDL cholesterol is called the ‘bad’ cholesterol because high levels in the bloodstream can clog your arteries.
- The Ugly: very low density lipoprotein (VLDL) cholesterol – these lipoproteins are the very large particles - high levels of VLDL cholesterol have been associated with plaque deposits on artery walls which narrow the passage and restrict blood flow.
Also making an appearance in your cholesterol count are:
- Triglycerides – these are the main storage form of fatty acids in the body. Most triglyceride in blood is found in the very large particles (VLDL). High triglyceride levels may contribute to hardening of the arteries and increase the risk of heart disease or stroke.
- Lipoprotein (a) – this is a substance made up of LDL "bad cholesterol" plus a protein (apoprotein a). Elevated levels are a very strong risk factor for heart disease - this is well established, yet few GPs check for it in their patients.
About ¾ of the cholesterol in our bodies is made in the liver and the rest comes from the types of fats we eat. Our genes also partly determine our blood cholesterol levels as do our diet and lifestyle. Cholesterol in food has only a very small effect on blood cholesterol, however eating too much saturated fat may lead to excess cholesterol in the blood stream.
What cholesterol levels should I be aiming for?
Australian health authorities recommend that total cholesterol levels should be no higher than 5.5 mmol/l if there are no other risk factors present. If there are other cardiovascular risk factors such as smoking, high blood pressure, diabetes, obesity or pre-existing cardiovascular (heart) disease, then total cholesterol should be less than 4.0 mmol/l.
A smart tool developed by the National Vascular Disease Prevention Alliance (NVDPA) (an alliance of Diabetes Australia, the National Heart Foundation of Australia, Kidney Health Australia and the National Stroke Foundation) calculates your absolute risk of heart disease (your chance of getting cardiovascular disease which includes all heart, stroke and blood vessel diseases) – you need to know your blood pressure as well as your total and HDL cholesterol to use this tool - https://www.cvdcheck.org.au.
Why is high cholesterol a problem?
Too much cholesterol circulating within LDL in our blood leads to fatty deposits developing in the arteries. This causes the vessels to narrow and they can eventually become blocked which can lead to heart disease and stroke.
If your cholesterol level is > 6.5 your risk of heart disease is about four times that of a person with a cholesterol level of 4.0.
Note that having high cholesterol levels doesn’t automatically mean you’ll develop heart disease – there are other genetic and physiological factors that influence this. But we do know that about 30% of Australians will die from heart disease and most of these will be over 65 years old. Heart disease takes a number of years to develop, so if you discover your cholesterol level is high you can start taking action to lower your cholesterol today, and monitor any changes in your levels regularly.
How can I lower my cholesterol?
You don’t need to eat foods that contain cholesterol as your body can produce all the cholesterol it needs. High-cholesterol foods are often also high in saturated fats and these foods should be limited in a healthy diet.
The cholesterol in your diet comes mainly from eggs and from animal products that are rich in fat such as meats and full fat dairy foods. All foods from animals contain some cholesterol whereas foods from plants do not contain cholesterol.
The most effective way to lower your LDL cholesterol is to reduce the amount of saturated fat and follow a healthy diet. By making the following changes to your diet you can expect your cholesterol to fall by 10%:
- Limit cakes, biscuits, pastries
- Use polyunsaturated or monounsaturated margarine or oils instead of butter
- Choose lean cuts of meat and remove visible fat
- Limit fatty meats, including sausages and salami
- Include more fish and beans in your meals
- Increase the amount and variety of fresh fruit, vegetables and wholegrain foods
- Choose low or reduced-fat milk, yoghurt and other dairy products
- Include foods in your diet that are rich in soluble fibre and healthy fats, such as nuts, legumes and seeds
- Limit cheese and ice cream to twice a week
Food components like saponins (found in chickpeas, alfalfa sprouts and other foods) and sulphur compounds like allicin (found in garlic and onions) may also have a positive effect in lowering cholesterol levels.
Plant sterols have also been shown to lower cholesterol levels and are found naturally in plant foods including sunflower and canola seeds, vegetable oils and (in smaller amounts) in nuts, legumes, cereals, fruit and vegetables. Some margarine and milks have concentrated plant sterols added to them and can lower LDL cholesterol.
What else can I do to lower my cholesterol?
Changing some of your lifestyle habits may also help to reduce your cholesterol and triglyceride levels. Suggestions include:
- Limit your alcohol intake to no more than one or two drinks a day and avoid binge drinking - this may help lower your triglyceride levels.
- Don’t smoke - smoking increases the ability of LDL cholesterol to get into artery cells and cause damage
- Exercise regularly e.g. at least 30 mins of brisk walking daily. Exercise increases HDL levels while reducing LDL and triglyceride levels in the body.
- Lose excess body fat - being overweight may contribute to raised blood triglyceride and LDL levels.
- Control your blood sugar levels if you have diabetes. High blood sugars are linked to an increased risk of atherosclerosis (‘hardening of the arteries’), heart attacks and strokes.
When should I consider medication?
If despite changes to your diet and lifestyle your cholesterol level remains stubbornly above 6.5 you may need medication, especially if you have other risk factors or have a family history of heart disease. Your GP is best able to advise you if medications may be needed to control cholesterol, triglycerides and other risk factors.
If you can measure it, you can manage it
Consider regular testing of your cholesterol levels and other heart disease risk factors. i-screen offers a range of health checks which include tests for key biomarkers which are known risk factors for heart disease. These include the more conventional tests such as total cholesterol, LDL cholesterol, HDL cholesterol, as well as C-reactive protein - a key marker of inflammation in the body. Elevated levels may indicate increased risk of cardiovascular disease or stroke.
i-screen also offers more specialised testing for heart disease risk factors including:
- Lipoprotein Particle Size – this test separates and quantifies all lipoprotein particles including the ‘large’, less atherogenic LDL-1 and LDL-2 and the ‘small’, highly atherogenic LDL-3 to LDL-7. The test also measures VLDL and IDL cholesterol.
- Lipoprotein (a) - Lipoprotein (a) has many properties in common with LDL but contains a unique protein, apolipoprotein (a) which is structurally different. Increased plasma lipoprotein (a) levels have been significantly correlated with cardiovascular disease.
- Apoliproteins - elevated levels of apolipoprotein B (a constituent of atherogenic lipoproteins), and reduced levels of apolipoprotein A-I (a component of anti-atherogenic HDL), are associated with increased cardiac events, and are believe to be a more reliable indicator of risk than traditional LDL and HDL measurements.
- Troponin - a study published on Christmas day 2016 has shown that a blood troponin test could be a more effective way of assessing future heart disease risk than blood pressure or cholesterol.
- Genetic testing – using specialised genomic testing we can identify hidden gene mutations that may promote chronic disease, prevent disease through early intervention, and modify gene expression through more precise, targeted, individualised interventions.
Whichever testing regime you decide on, monitoring changes in your health data over time typically provides greater insight than a single isolated result, and will allow you to track any improvements or declines in performance. This means you can monitor the effectiveness of any diet and lifestyle changes you have adopted, or measure the effects of any cholesterol moderating medications.
