Most of the cholesterol in your blood is made by your own body, primarily in the liver, from where it’s released into the bloodstream.
There are two main types of cholesterol:
According to the National Heart Foundation, 51 percent of Australian adults have blood cholesterol levels that are higher than recommended and are consequently at increased risk of coronary artery disease and related conditions such as heart attack and stroke.
Having high blood cholesterol levels is a form of a condition known as hyperlipidaemia.
The causes of high cholesterol are complex and depend on many factors.
These include genetics, your age, gender, eating habits, body weight and shape, level of physical activity and whether you have other health problems, such as diabetes.
Some foods contain high levels of cholesterol, including egg yolks, liver, butter and shellfish such as prawns. However, while the quantity of cholesterol you eat does have some effect on your overall blood cholesterol levels, it’s not the major determinant.
Generally speaking, the level of saturated fat you consume affects blood cholesterol levels more than how much cholesterol you eat. This is because the way saturated fats are processed by the liver causes it to increase cholesterol production – and in particular, production of LDL cholesterol.
Saturated fats come from animal products, notably the visible fat on meat, in offal such as liver, in processed meat products such as salami and in dairy products, especially butter and some cheeses.
Ordinarily, if you eat prawns or any other high cholesterol foods, your liver will compensate by making less cholesterol and your overall cholesterol levels will not be dramatically affected.
The exception is people who have a genetic condition known as familial hypercholesterolemia.
Having a problem with fat (or lipid) levels in the blood – either too much or too little – is known medically as ‘dyslipidaemia’. One form of dyslipidaemia is hyperlipidaemia, which is when you have too much of, or cannot properly process, fats and cholesterol in the blood.
Some forms of hyperlipidaemia are genetic – which means it can be passed down through families.
One such condition is familial hypercholesterolemia (FH), which causes very high LDL cholesterol levels due to an abnormality in the gene responsible for removing LDL cholesterol from the blood.
FH can lead to the onset of coronary artery disease at an early age – typically in the 30s or 40s. In rare cases, people who have two parents who carry the abnormal gene may have a more extreme form of FH and experience coronary artery disease in childhood or adolescence.
Treatment for FH is similar to treatment for other forms of high cholesterol, but is more likely to include the combination of several different medications and the need to take even greater care with limiting saturated fat and foods that contain high levels of cholesterol.
In its initial stages, high cholesterol generally has no symptoms. You can be feeling perfectly fine and still have elevated cholesterol levels. That’s why it’s so important to have your blood tested regularly.
However, if high cholesterol levels are unchecked they can lead to coronary artery disease and you may experience angina, or have a heart attack and stroke. You might think it odd that stroke is included in coronary artery disease but that’s because it’s caused by the same arterial problems and shares the same risk factors. People at risk of heart attacks are also at risk of stroke and vice versa.
Because they are so strongly interrelated, many factors that increase your risk of high cholesterol are the same as the general risks outlined for coronary artery disease.
These include having related medical conditions, various lifestyle factors, heredity and demographics.
Similarly, the symptoms, diagnosis and treatment options are also in line with those for coronary artery disease.
As with general coronary artery disease risk factors, many of the risks for high cholesterol are modifiable: that is, they’re in your control and you can make a difference to how they affect your life.
Next: DiabetesTop of page
This information has been developed and reviewed for Bupa by health professionals. To the best of their knowledge it is current and based on reputable sources of medical research. It should be used as a guide only and should not be relied upon as a substitute for professional medical or other health professional advice.
Bupa Australia Pty Ltd makes no warranties or representations regarding the completeness or accuracy of the information. Bupa Australia is not liable for any loss or damage you suffer arising out of the use of or reliance on the information. Except that which cannot be excluded by law. We recommend that you consult your doctor or other qualified health professional if you have questions or concerns about your health. For more details on how we produce our health content, visit the About our health information page.
Last published 31 October 2011