Cholesterol is a fatty substance that is a part of all animal cells. You need cholesterol – without it, your body couldn’t make vitamin D or hormones such as oestrogen and testosterone. It also serves other processes in the brain, nervous and digestive systems, such as helping your body to absorb fat from the food you eat.
So why do you need to worry about maintaining a healthy level of cholesterol in your body? The primary problem is when too much cholesterol gets into your blood as it can damage arteries and contribute to heart disease. Elevated levels of blood cholesterol are common. According to the Baker IDI Heart and Diabetes Institute, about half of all Australian adults have this problem. Men generally have higher blood cholesterol levels than women, though this may change after menopause when women’s levels of blood cholesterol often increase, along with their risk of heart disease.
‘Good’ cholesterol vs. ‘bad’ cholesterol
Cholesterol is a fat that needs special proteins to transport it around the body. Low-density lipoproteins (LDL) carry cholesterol to your cells and at high levels it can cause fatty deposits (plaques) to form in your arteries. These deposits cause the arteries to become narrow, increasing the risk of blocked arteries that lead to heart attacks and stroke. This is why LDL cholesterol is considered ‘bad’ cholesterol.
High Density Lipoprotein (HDL) cholesterol, on the other hand, is considered ‘good’ cholesterol. HDL transports excess cholesterol out of cells in your body, including in your arteries, and back to the liver where it’s either re-used or removed from your system.
What is a healthy level of blood cholesterol? Below are the fasting blood cholesterol levels suggested by the National Heart Foundation Lipid Management Guidelines.
| |
Healthy adults |
Adults with or at high-risk of
coronary heart disease |
| Total cholesterol |
Below 4.0 mmol/L |
N/A/ |
| LDL cholesterol |
Below 2.5 mmol/L |
Below 2.0 mmol/L |
| HDL cholesterol |
Above 1.0 mmol/L |
Above 1.0 mmol/L |
A healthy blood cholesterol level for you may depend on whether or not you already have any risk factors for heart disease such as a family history of heart disease, high blood pressure or diabetes, or if you already have a heart condition. You should discuss your heart health and your cholesterol levels with your doctor if you have any concerns.
How do unhealthy levels of ‘bad’ cholesterol come about?
Your liver makes cholesterol from saturated fats, so you only need to eat a small amount of cholesterol in your diet to satisfy your body’s cholesterol needs. However, foods that are high in cholesterol, such as animal livers, egg yolks and prawns, only have a small effect on the levels of LDL cholesterol in your body, according to the Heart Foundation. Unhealthy levels of ‘bad’ LDL cholesterol generally happen when your liver makes too much cholesterol instead.
Your liver makes too much cholesterol when you have too much saturated fats, particularly trans fats, in your diet. Saturated fats, which are found in meat, full-fat dairy products and many processed foods, raise ‘bad’ LDL cholesterol. Trans fats are more problematic because they raise ‘bad’ LDL cholesterol’ and lower ‘good’ HDL cholesterol levels at the same time. Although trans fats are found naturally in small amounts in animal foods like meat and dairy products, the main source of trans fats in a Western diet is from some manufactured foods, where they are created during food processing. Trans fats are most likely to be in processed baked goods like cakes, pies, pastries and biscuits and in deep-fried foods.
The good news is that poly- or mono- unsaturated fats can help keep levels of blood cholesterol healthy. These fats can be found in oily fish, seed oils, olive oil, nuts and avocados, for example.
How can I keep cholesterol levels healthy?
In general, the lower your LDL cholesterol and the higher your HDL cholesterol, the better your chances of preventing heart disease and other chronic conditions.
Here are some simple ways you can lower your ‘bad’ LDL cholesterol levels to lower your risk of heart disease:
- Exercise regularly
- Aim for a healthy body weight
- Avoid trans fats
- Limit foods rich in saturated fat, like red meat and whole milk, ice cream, and other full-fat dairy foods
- Focus on foods rich in unsaturated fats, dietary fibre, and healthy protein-containing foods. Fruits, vegetables, fish, beans, nuts and seed are all excellent choices. Other foods that help lower cholesterol are oats, plain unsalted nuts, margarines with plant sterols, barley, flaxseed, psyllium, lentils, and soy milk and soy products.
When should I get my cholesterol checked?
If you are over 18 years old, you should consider having your cholesterol levels checked at least every five years. It’s just a simple blood test taken after fasting for 12 hours. If you have a higher risk of coronary heart disease such as a family history of high cholesterol, heart disease, high blood pressure and/or diabetes you may want to have tests more frequently. The Heart Foundation recommends all adults over 45 have a regular blood cholesterol test every few years.
Seeing your doctor regularly is also necessary to keep an eye on your cholesterol levels and general heart health. If your total and LDL cholesterol levels remain high after adjusting your diet and doing appropriate exercise, you should discuss any further checks and treatment to get your levels into an ideal range with your doctor.
Further information
Heart Foundation www.heartfoundation.org.au
Sources
Australian Better Health Initiative. Types of fat and the role of cholesterol. [online] Canberra, ACT: Commonwealth of Australia. c2007. [updated 12 Nov 2008, accessed 6 Aug 2010]. Available from: www.measureup.gov.au/internet/abhi/publishing.nsf/Content/Types of fat and the role of cholesterol-lp
Baker IDI. Cholesterol and your health. [online] Melbourne, VIC: Baker IDI Heart and Diabetes Institute. 2009. [accessed 9 Aug 2010]. Available from: www.bakeridi.edu.au/health_fact_sheets/cholesterol_your_health/
Harvard School of Public Health. Fats and Cholesterol: Out with the Bad, In, with the Good. [online] Boston, MA: The President and Fellows of Harvard College. c2010. [accessed 6 Aug 2010] Available from: www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-full-story/index.html
National Health and Medical Research Council. Dietary Guidelines for all Australians. [online]. Canberra: ACT: Commonwealth of Australian. 2003 [accessed 4 Aug 2010] Available from: www.nhmrc.gov.au/publications/synopses/dietsyn.htm
National Heart Foundation of Australia and the Cardiac Society of Australia and New Zealand. Position Statement on Lipid Management – 2005. Heart Lung and Circulation. 2005; 14: 275-291.
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