Low-density lipoprotein, also called LDL, is part of the total cholesterol level, along with high-density lipoprotein, called HDL. While LDL is called the "bad" type of cholesterol, it has a definite purpose in your body and only causes problems if the blood levels rise higher than normal. Elevated LDL levels normally cause no symptoms. Blood tests can diagnose high LDL levels.
Purpose
Both LDL and HDL carry cholesterol through the bloodstream. Low-density lipoprotein carries about 75 percent of the body's cholesterol from the liver to cells in the body that require cholesterol to function, the University of Maryland Medical Center, or UMMC, reports. High-density lipoprotein improves cholesterol levels by carrying excess amounts of cholesterol back to the liver for excretion.
Normal Limits
A serum LDL level of less than 100 mg/dL is considered optimal. A level of 100 to 129 mg/dL is considered near optimal and 130 to 159 mg/dL is considered borderline high. Levels over 160 mg/dL are considered high, with levels over 190 mg/dL very high.
Risk Factors
A number of factors increase your risk of having high LDL levels. People who inherit a certain type of LDL called Lp(a) can have high LDL levels. Inherited high cholesterol levels affect one in 500 people, UMMC states. Smoking, diabetes, high blood pressure, inactivity and being overweight also increase your risk of having high LDL levels.
Dangers
Having elevated LDL levels increases your risk of developing atherosclerosis, plaque buildup on the inside of arteries that narrows and harden the arteries, making them less flexible. Atherosclerosis can cause a heart attack if the heart doesn't receive enough oxygen through narrowed or blocked blood vessels, the American Heart Association reports. Low-density lipoprotein that sticks to the artery walls also causes inflammation that further damages the arteries. Blood clots that form at the damaged site can break loose and travel through the bloodstream, lodging in the blood vessels and possibly causing a stroke.
Treatment
Avoiding behaviors that increase the risk of developing high LDL levels and decreasing saturated fats in the diet can help decrease LDL levels. Your medical practitioner may recommend taking medications that lower cholesterol levels if your LDL levels reach 160 mg/dL and you have one other risk factor for heart disease, or if your levels reach 130 mg/dL and you have two other risk factors. If your LDL levels exceed 190 mg/dL, you should take cholesterol-lowering medications, UMMC recommends.
