A lipid is a fat-like substance in the body that is greasy or oily. There are two types of lipids: cholesterol and triglycerides. They are measured by a simple blood test called a fasting lipid profile.
Cholesterol and triglycerides travel through the body in “packages” called lipoproteins. Lipoproteins are made up of a lipid and a protein, each of which is in different amounts within the lipoprotein “package.” Lipoproteins are the vehicle by which cholesterol and triglycerides move through the bloodstream and to other parts of the body.Cholesterol
Cholesterol is found in all parts of the body. Our livers produce it and we consume it in meat and dairy products. Cholesterol provides structure to cell membranes and plays an important role in the development of cell walls and hormones in the body. Too much cholesterol in the blood, however, can stick to the walls of the arteries and increase the risk of developing atherosclerosis (hardening of the arteries or clogged arteries).
There are two basic kinds of cholesterol: the “bad” low-density-lipoprotein (LDL) cholesterol, and the “good” high-density-lipoprotein (HDL) cholesterol.
The “bad” LDL cholesterol has a small amount of protein and a large amount of lipid. LDL tends to settle in the artery walls, where it can build up and cause a narrowing or blockage in the arteries. That’s why high levels of LDL are considered bad for your health.
The “good” HDL cholesterol has a large amount of protein and a small amount of lipid. HDL helps to remove bad cholesterol from the blood by “picking it up” and carrying it to the liver, where it is broken down and excreted by the body as waste. That’s why high levels of HDL are considered good for your health.
Triglycerides
Triglycerides are another form of fat detected in the blood. It is made by the body and comes from the food we eat. Triglycerides are the chemical form in which most fat exists in food and in the body. In addition to being derived from fats in foods, triglycerides are made in the body from other energy sources, such as carbohydrates. Calories ingested at a meal and not immediately used by tissues are converted into triglycerides and transported to fat cells to be stored. Hormones regulate the release of the stored triglycerides to meet the body’s need for energy between meals. Like cholesterol, a high level of triglycerides has been linked to coronary artery disease in some people. High triglycerides also increase the risk of becoming overweight, and of developing diabetes and hypertension (high blood pressure).
Ideal Lipid Levels
A fasting lipid profile provides four measurements: total cholesterol, LDL, HDL and triglycerides:
- Total cholesterol is a measure of all the cholesterol and triglycerides in your blood. It is measured in milligrams per deciliter (mg/dl). It’s desirable to have a total cholesterol level under 200; at 240 and over, you are at high risk of heart disease.
- The lower your LDL level, the better. Your LDL should be less than 100, but a level of 100-129 ranges from near optimal to above optimal. LDL levels of 130-159 are borderline high, and those at 160 or above are too high.
- The higher your HDL level, the better. Levels of 60 and above are optimal. HDL of less than 40 for men and less than 50 for women puts you at higher risk of heart disease.
- Triglyceride levels of less than 150 are normal. Levels of 200 or higher are too high.
- Several factors affect cholesterol and triglyceride levels. These include medications, illness, heredity, diet, exercise, smoking and alcohol consumption. Talk to your healthcare provider about how you might improve your blood lipid profile.