What is cholesterol? What's the difference between good cholesterol (HDL) and bad cholesterol (LDL)? Find out from the Department of Dietetics at Singapore General Hospital.
Dietary changes can play a part in lowering cholesterol levels
If you’ve been told that you have high blood cholesterol, don’t worry. Making some changes to your diet can go a long way towards lowering your cholesterol levels.
“By cutting back on unhealthy fats and replacing these with ‘healthier options’, and eating more fibre-rich foods, many people see a drop in their cholesterol levels and may be able to avoid taking cholesterol-lowering medication,” says Ms Apple Chan Li Ping, Dietitian, Department of Dietetics, Singapore General Hospital (SGH), a member of the SingHealth group.
What is cholesterol?
Cholesterol is a fat-like substance that your body naturally produces. It’s needed for a variety of functions, including the formation of cell membranes and production of certain hormones, vitamin D and bile acids.
You can have an excess of cholesterol if your body makes more than it needs, or if there is too much cholesterol in your diet (as your body doesn’t adjust its own production accordingly).
Lipids (fat) such as cholesterol are insoluble in water and therefore carried throughout the body by special proteins called lipoproteins. There are two types of lipoproteins, which are commonly known as low density lipoprotein (LDL) and high-density lipoprotein (HDL).
LDL: LDL brings the cholesterol to where it’s needed in the body. However, if there’s an excess of LDL cholesterol in the bloodstream, it gets deposited on the walls of arteries, creating a build-up known as plaque. Over time, this build-up of plaque causes the arteries to narrow and can result in a heart attack or stroke if the blood flow to the heart or brain gets cut-off. That’s why LDL-cholesterol is called the ‘bad’ cholesterol.
HDL: HDL is called the ‘good’ cholesterol because it carries excess cholesterol circulating in the bloodstream back to the liver where it is broken down and eliminated. A high level of HDL-cholesterol lowers your risk of developing plaque in your arteries and protects you against heart disease and stroke.
Cholesterol in a nutshell
High LDL-cholesterol can increase your risk of heart disease and stroke, and high HDL-cholesterol counteracts this risk. Your total cholesterol includes both your LDL and HDL. ‘High cholesterol’ typically refers to high LDL-cholesterol.
Singapore’s Health Promotion Board (HPB) recommends the following cholesterol levels as optimal for both men and women:
- Total cholesterol less than 200 milligrams per deciliter (mg/dL) or 5.2 mmol/L
- LDL cholesterol less than 130 mg/dL or 3.3 mmol/L
- HDL cholesterol greater than 40 mg/dL or 1.0 mmol/L