Cholesterol is a fatty substance known as a lipid. While some foods contain lipids, most of them are produced by your liver and are vital to normal body function. The lipids get carried around the body by proteins in the blood.
This combination is called lipoprotein, and there are two important types:
High-density lipoprotein (HDL), or 'good cholesterol', carries cholesterol away from the cells back to the liver where it’s broken down or disposed of as waste product. High levels of HDL are good for you while low levels heighten your risk of cardiovascular disease, even if your bad cholesterol is low.
Low-density lipoprotein (LDL), or ‘bad cholesterol’, actually performs a vital task in carrying cholesterol to the cells that need it. But if the levels are higher than needed, excess cholesterol can lead to plaque build-up in the arteries, increasing the risk of heart and cardiovascular diseases including stroke and heart attack. These acute conditions happen when the plaque deposits come loose and lodge in smaller arteries, suddenly cutting off blood to the heart or brain. Chronic narrowing of the arteries can also induce angina attacks and serve to raise your blood pressure, which in itself is a health risk.
A pin-prick blood test can reveal the levels of good and bad cholesterol in your blood. It’s expressed as millmoles per litre of blood (mmol/L). Generally, levels should not exceed:
- Total cholesterol (TC) - 5mmol/L or less for healthy adults, or 4mmol/L or less for those at high risk
- LDL – 3mmol/L or less for healthy adults, or 2mmol/L or less for those at high risk
- HDL – should be 1mmol/L or above. Less than this can increase your risk of heart disease.
A strong indicator of cardiovascular health is your TC:HDL ratio. Divide TC by HDL to produce a number. A result of less than four is considered healthy, the lower the number the better.
What to do if you have high cholesterol
- Increase your activity. Read: 5 exercise tips to control cholesterol levels
- Eat for good cholesterol, not bad. Read: 5 eating tips to help bring your cholesterol level down
- If you smoke, stop
- Reduce alcohol consumption
- Take steps to reduce your blood pressure
- If you are at high risk, you may be prescribed medication by your GP.
Last updated Monday 25 April 2022
First published on Tuesday 22 November 2016