Lipids are fatty substance in the blood that are involved in many body processes. Lipid disorders are abnormal levels of these lipids in the blood. Cholesterol and triglycerides are two types of lipids that are measured.

High cholesterol levels are associated with an increased risk of heart disease, hardening of the arteries (atherosclerosis), and stroke.

A total cholesterol level of:

• Less than 200 mg/dL* (5.2 mmol/L) is desirable
• 200-239 mg/dL (5.2-6.1 mmol/L) is borderline high
• Over 239 mg/dL (6.1 mmol/L) is high

*mg/dL = milligrams per deciliter blood (mmol/L = millimoles per liter blood)

Plaque Due to Build-up of Lipids in an Artery

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There are two main types of cholesterol:

• High-density lipoprotein (HDL) cholesterol—This is often referred to as the "good" cholesterol because it helps to protect against heart disease. HDL may carry cholesterol to the liver and away from arteries. Levels of 60 mg/dL (1.6 mmol/L) or higher are beneficial in lowering heart-disease risk. Levels below 40 mg/dL increase your risk for heart disease.
• Low-density lipoprotein (LDL) cholesterol—This is often referred to as the "bad" cholesterol because it increases the risk of heart disease. High levels allow plaque to build up in your arteries. Levels less than 100 mg/dL (2.6 mmol/L) are considered optimal.

Triglycerides also contribute to heart disease in some people. Levels from 150-199 mg/dL are borderline high and above 199 mg/dL (5.2 mmol/L) are considered high. Higher levels tend to run in families or people with central (abdominal) obesity.

Factors such as heredity, certain drugs, and diets high in saturated and trans fat can lead to unhealthy elevations in lipid levels. Large amounts of carbohydrates or alcohol may also lead to high lipid levels.