Cholesterol serves important functions in the body. It helps maintain proper fluidity and permeability in cell membranes and aids in the synthesis of fat-soluable vitamins, steroid hormones, and sex hormones.
Cholesterol is transported to and from cells by lipoproteins. Low-density lipoprotein (LDL) is known as “bad” cholesterol, while high-density lipoprotein (HDL) is known as “good” cholesterol. LDL, HDL, triglycerides, and other lipid components make up total cholesterol.
Excessive amounts of cholesterol in the bloodstream are associated with atherosclerosis
—a waxy build-up of plaque in the blood vessels that can lead to heart attack or stroke. Low HDL cholesterol levels are a major factor for heart disease.
• The American Heart Association (AHA) recommends individuals aged 20 years or older have their cholesterol levels tested every 5 years.
• 106.7 million Americans aged 20 years and older have total cholesterol levels ≥200 mg/dL.
• 37.2 million Americans aged 20 years and older have total cholesterol levels ≥240 mg/dL.
Blood cholesterol levels are most accurately assessed with a fasting lipoprotein profile—a blood test done after a 9- to 12-hour period without food, beverages, or medications. This laboratory test measures LDL, HDL, and triglyceride levels. OTC cholesterol testing kits are also available.
To reduce the risk of heart disease in adults:
• Total cholesterol levels should be below 200 mg/dL.
• LDL cholesterol levels should be below 100 mg/dL.
• HDL cholesterol levels should be above 40 mg/dL for men and 50 mg/dL for women.
• Triglyceride levels should be below 150 mg/dL.
• Children aged 2 to 19 years should have total cholesterol levels below 170 mg/dL and LDL cholesterol levels below 110 mg/dL.
To reduce the risks of atherosclerosis, heart disease, and stroke, individuals can:
• Avoid smoking and alcohol
• Get regular aerobic exercise
• Avoid or reduce obesity
• Eat a heart-healthy diet rich in fiber, fruits and vegetables, and lean proteins
• Identify and treat diabetes
• Identify and treat hypertension
Patients with elevated cholesterol levels who cannot control cholesterol with lifestyle changes are most commonly prescribed one of the following therapies:
• HMG-CoA reductase inhibitors
, or statins, are the most commonly prescribed; they reduce LDL cholesterol levels in the blood.
• Bile acid sequestrants
also lower levels of LDL cholesterol, but they tend to raise triglycerides.
• Nicotinic acid
is a form of niacin; it raises HDL cholesterol levels and lowers triglycerides/LDL cholesterol.
• Fibric acid derivatives
lower levels of triglycerides and raise levels of HDL cholesterol.
• In February 2010, the FDA approved the use of rosuvastatin calcium (Crestor) to protect against cardiovascular problems in individuals with normal levels of cholesterol but other heart disease risk factors.
• A recent study found that diets highest in sugar were linked to the lowest levels of HDL cholesterol and the highest levels of triglycerides. The AHA recommends that individuals limit their sugar intake to 100 calories per day for most women (about 6 tsp) and 150 calories per day for most men (about 9 tsp).
• Dietary supplements such as niacin, soy, and flaxseed oil have been studied for their potential to reduce cholesterol, but evidence of their effectiveness has been inconclusive. ■
Resources for Patients
For more information about reducing cholesterol, visit these Web sites:
• American Heart Association
• Centers for Disease Control and Prevention
• National Heart, Lung, and Blood Institute