Lipids are a group of molecules with specific properties (e.g. they don’t dissolve in water). Several different lipids are found in your body and blood.
The ones that are measured in routine blood tests to assess heart problems are called cholesterol and triglycerides.
Triglycerides are also commonly known as ‘fat’ (like the white rind on bacon or beef). It is used in your body as fuel to power muscles. It is also stored under the skin and around your internal organs. Too much ‘in storage’ can lead to obesity.
Cholesterol is used in all cell membranes, and for making hormones like oestrogen and testosterone. For most people, about 80% of the cholesterol in their blood is made by their own liver.
The remaining 20% comes from the food that they eat. Food like meat, poultry, eggs, fish and dairy products are very high in cholesterol. Foods that come from plant sources contain very little or no cholesterol.
What is good and bad cholesterol?
Because it does not dissolve easily in water, cholesterol cannot travel freely in blood. Instead, it is carried on special carrier proteins called lipoproteins.
Some of these lipoproteins deposit cholesterol in the blood vessels, and some of them actually ‘mop up’ excess cholesterol in blood vessels.
Too much cholesterol in blood vessels and in heart valves can lead to blockages and blood clots. The lipoprotein that collects the cholesterol and takes it back to liver is often called “good cholesterol”. The lipoprotein that drops off cholesterol is called “bad cholesterol”.
Your health care team will talk to you about your cholesterol and will measure the amounts of these lipoproteins in your blood.
The medical terms used for good and bad cholesterol are:
- Low-density lipoprotein (LDL) (bad cholesterol)
- High-density lipoprotein (HDL) (good cholesterol)
The second main type of lipids measured in your blood are called triglycerides (TG). TG are also used to make cell membranes and they are the type of fat that is stored under the skin, especially around the waist, stomach, buttocks and thighs.
Saturated TG are solid at room temperature and can be seen in meat (e.g. the white layer on bacon). These saturated fats release a lot of TG into your blood when you digest them.
Doctors are interested in the different levels of these lipids in your blood because changes in the ratios of different lipid levels are be associated with a very high risk of arterial stenosis as well as other cardiovascular diseases, and stroke.
Although your body makes most of its own cholesterol and stores TG fat, you can also change the levels of lipids in your blood by what you eat, and how you exercise because TG fats are also used as energy to fuel muscles.
General guidelines for healthy cholesterol levels include: LOCAL INPUT REQUIRE
- Total cholesterol should be less than 200 mg/dL
- Low-density lipoprotein (LDL) or “bad” cholesterol should be less than 100 mg/dL
- High-density lipoprotein (HDL) or “good” cholesterol should be higher than 60 mg/dL
- Triglycerides should be less than 150 mg/dL
There are several ways you can improve your blood lipid levels:
- Get at least 30 minutes of moderate physical activity every day, most days of the week.
- Eat a diet low in saturated fat and cholesterol.
- Choose a diet that is rich in fruit, vegetables and whole grains.
- If you are not already at a healthy weight for your height, lose weight.
- Take cholesterol-lowering medication, such as statins, if you are advised to do so by your doctor.