High cholesterol. TV commercials, magazine ads and pamphlets at your doctor's office warn of its dangers. But you've never worried about cholesterol or heart problems. You feel healthy. Why do you need a cholesterol test?
What is cholesterol?
Cholesterol is a fat-like substance made by your body. Your body uses it to build cells and other things. About 75 percent of the cholesterol in your blood is made by your body. The rest comes from food you eat. Animal products (meat, eggs and dairy) are sources of cholesterol. Foods high in saturated fats and trans fats also raise cholesterol.
Cholesterol moves through your blood attached to lipoproteins. The two lipoproteins we talk about are high-density (HDL), often known as the "good" cholesterol, and low-density (LDL), often known as the "bad" cholesterol.
Your body usually only makes as much cholesterol as you need. But sometimes it can make too much (this condition tends to run in families). Or your diet may include too many fatty, cholesterol-rich foods. When there is too much cholesterol in your blood, it can build up inside your arteries.
The good and the bad
A cholesterol screening measures the amount of cholesterol in your blood. Tests may be fasting or non-fasting. In a fasting test, blood is drawn after nine to 12 hours without food. This gives doctors the most complete results. You'll learn your total cholesterol level and your levels of HDL and LDL cholesterol. The test will also show your level of triglycerides, which are a type of fat. A non-fasting test will show only your total and HDL levels.
You want this to be less than 200 mg/dL. Total cholesterol of 240 mg/dL is high.
LDL is the "bad" cholesterol because it carries cholesterol to your arteries. Higher levels of LDL cholesterol are linked to an increased risk for heart disease. Here's what the LDL levels mean.
- Less than 100 mg/dL: Optimal
- 100-129 mg/dL: Near optimal
- 130-159 mg/dL: Borderline high
- 160-189 mg/dL: High
- 190 mg/dL or above: Very high
HDL is the "good" cholesterol. It removes cholesterol from arteries so it can be expelled from the body. Higher levels of HDL cholesterol can mean a lower risk of heart disease. Less than 40 mg/dL for men and less than 50 mg/dL for women means you could be at risk of heart disease. An HDL higher than 60 mg/dL means you may be protected.
There's no way to know if you have a lot of good HDL or bad LDL cholesterol without a blood test.
Risks of high cholesterol
Experts disagree about when and how often you need to have your cholesterol checked. It may depend on your known risk factors. But experts agree that knowing your cholesterol levels is beneficial.
People with high cholesterol may feel perfectly healthy. Cholesterol buildup can happen very slowly. Unfortunately, a heart attack or stroke may be your first sign of trouble.
Here's what can happen: LDL cholesterol builds up inside your arteries. Plaque, a mixture of cholesterol and other fats, forms along the artery walls. This makes your arteries narrower and harder. This is called atherosclerosis. Sometimes plaque tears, causing a blood clot to form. If the clot is big enough, it can block the narrowed blood vessel. If this happens in a coronary (heart) artery, it's a heart attack. If it happens in the brain, it's a stroke.
The higher your cholesterol levels, the higher your risk of heart attack or stroke. You are also at higher risk of coronary heart disease.
High cholesterol is treatable, but you have to know you have it! Adopting a diet low in cholesterol, saturated fats and trans fats is a good start. So is developing an exercise plan with guidance from your doctor. If you smoke, quit. Some people may need medication to help lower their LDL cholesterol.
Created on 02/07/1999
Updated on 01/30/2013
- National Heart, Lung and Blood Institute. Do you know your cholesterol levels?
- UpToDate.com. High cholesterol and lipids (hyperlipidemia).
- Agency for Healthcare Research and Quality. Treating high cholesterol: A guide for adults.
- American Heart Association. Cholesterol.