|Common Lipids. Eoin Fahy, GNU license|
Ideal cholesterol levels vary based on a person’s other risk factors, including age, gender, and family history. However, doctors follow particular guidelines when assessing an individual’s risk for cholesterol-related diseases. Lipid panels generally consist of LDL, HDL, and total cholesterol levels, as well as triglycerides. But sometimes other types of cholesterol in the blood are measured to indicate a risk of heart disease and to determine if intervention is necessary.
What is cholesterol?
Cholesterol is a fatty, waxy substance made by the human body. It is also present in some foods and a necessary molecule used by various tissues in the body to make certain vitamins and hormones, but high levels of cholesterol in the blood can lead to deposition in the arteries and some tissues, causing blockage (atherosclerosis) and disease over time.
Triglycerides are free fats measured on lipid panels alongside cholesterol. High levels indicate circulating lipids that can accumulate in plaques with cholesterol. The guidelines noted below recommend keeping triglyceride levels below 150 mg/dL (milligrams per deciliter, the standard measure used in the United States).
Lipoproteins are molecules made of fat and protein. These molecules carry cholesterol around the body, allowing it to pass in and out of cells as needed. A standard lipid panel measures two types of lipoproteins, LDL and HDL. LDL stands for low density lipoprotein (or “bad” cholesterol), and HDL represents high density lipoprotein (or “good” cholesterol).
Based on guidelines set by the National Institutes of Health National Cholesterol Education Program, the optimum LDL value is less than 100 mg/dL, and HDL values should be above 60 mg/dL. However, individuals with no other risk factors for heart disease can consider an LDL level between 100 and 130 mg/dL acceptable, and individuals with a family history of cholesterol-related disease should aim for less than 70 mg/dL. Ideally, the LDL to HDL ratio should be 3.5 to 1, with recommendations to maintain it no higher than 5:1.
Though not part of the standard lipid panel, other lipoproteins are sometimes considered in cholesterol evaluations, particularly lipoprotein(a) and VLDL.
Lipoprotein(a) is LDL with an apolipoprotein A molecule attached. Recent research has found that high levels of this molecule in the blood are a risk factor for heart disease. A value of less than 30 mg/dL is generally considered the target, though the normal range will vary by laboratory. For VLDL (very low density lipoprotein) the target range is 5 ro 40 mg/dL. However, VLDL is usually determined as a percentage of the triglyceride levels and not measured directly.
The last measure included on lipid panels is total cholesterol, a measure that takes into account all forms of cholesterol in the blood. The total cholesterol level should ideally be less than 200 mg/dL.