Cholesterol is a form of fat we need. It helps make the outer membranes of our bodies' cells stable. But for decades, doctors have known that people with high total cholesterol levels are more likely to get heart disease. More recently, they've found the different forms of cholesterol ("good" and "bad") also play a role. High total cholesterol, high bad cholesterol, or low good cholesterol could raise your chances.
For example, LDL, or "bad," cholesterol can stick to blood vessel walls. Over years, it can play a role in clogging arteries in a process called atherosclerosis. Narrowed arteries in your heart can then develop sudden blood clots, causing heart attacks.
Cholesterol Tests: The Good, the Bad, and the Fatty
The different kinds of cholesterol and other fats in your blood are together called lipids. Doctors measure and diagnose lipid problems with a simple blood test. You'll probably have to fast for 9 to 12 hours before it to make sure it's not affected by any food you recently ate.
A lipid profile usually gives results for four different types:
- Total cholesterol
- LDL (low-density lipoprotein), the "bad cholesterol"
- HDL (high-density lipoprotein), the "good cholesterol"
- Triglycerides, another form of fat
Some lipid panels can give even more detailed information, like the presence and sizes of various fat particles in your blood. Researchers are looking into what, if any, effect these traits have on heart disease. There's no clear guidelines on when this more advanced testing is needed.
Your Cholesterol Test Results
So you've gone hungry overnight, endured a small bloodletting, and dutifully returned to get your results. Now, what do the numbers mean?
For total cholesterol:
- 200 milligrams per deciliter (mg/dL) or less is normal.
- 201 to 240 mg/dL is borderline.
- More than 240 mg/dL is high.
For HDL ("good cholesterol"), more is better:
For LDL ("bad cholesterol"), lower is better:
- Less than 100 mg/dL is ideal.
- 100 to 129 mg/dL can be good, depending on your health.
- 130 to 159 mg/dL is borderline high.
- 160 to 189 mg/dL is high.
- 190 mg/dL or more is very high.
Your doctor will consider your overall likelihood of heart disease to set your personal LDL goal. For people at great risk of heart disease, or who already have it, your LDL should be less than 100 mg/dL. (Your heart doctor might recommend an even lower LDL -- less than 70 mg/dL -- if your risk of heart disease is very high.) If you have a moderately high chance, an LDL less than 130 mg/dL is your target. If you're not likely to get heart disease, less than 160 mg/dL is probably fine.
High triglycerides (150 mg/dL or greater) also raise the odds for heart disease somewhat.
What You Can Do About Abnormal Lipid Levels
Lifestyle changes are the first thing to tackle to reduce your chance of heart disease.
A cholesterol-lowering diet can bring down bad cholesterol by up to 30%. A diet low in saturated fat (7% of total calories or less) and no more than 200 mg of cholesterol daily can lower LDL cholesterol. Fiber and plant sterols (found in special margarines and other foods) help, too.
Regular aerobic exercise can both lower bad cholesterol (LDL) and raise good cholesterol (HDL).
- Statins, the most effective and commonly used cholesterol drugs
- Bile acid sequestrants
Your cholesterol numbers don't determine your destiny. Remember, other things besides cholesterol can also lead to heart disease. Diabetes, smoking, high blood pressure, obesity, exercise, and genetics are important as well.
People with normal cholesterol can have heart disease; people with high cholesterol can have healthy hearts. Overall, though, more people whose cholesterol levels are off will get heart disease.
Experts recommend follow-up cholesterol testing every 5 years for most people. If your lipid results aren't what you and your doctor had hoped for, or if you have other reasons to be concerned about heart disease, you'll need cholesterol tests more often.