Cholesterol. You have heard it is "bad for you," but why? Where does it come from? Why is it a cause for concern?
What Is Cholesterol?
Cholesterol itself is not bad. It is a type of fat that has several important roles in the body such as:
- Vital component of all cell membranes and tissue that protects nerve cells
- Backbone of many hormones including estrogen, progesterone, and testosterone
- Assists in creation of vitamin D and bile, a substance that helps digest fat
Problems occur when the levels of cholesterol in the blood get too high. This fat causes a build up of plaque in the blood vessels. Over time this build up increases the risk of cardiovascular disease such as heart disease or stroke.
Where Does Cholesterol Come From?
Cholesterol comes from internal and external source. Your liver creates cholesterol but you also take in cholesterol through your foods. Dietary cholesterol comes from animal products, such as meat, milk, cheese, and butter.
What Are the Types of Cholesterol?
Not all cholesterol is the same, there are several subtypes with important differences. Two more common subtypes include:
- Low Density Lipoproteins (LDLs)—LDLs make up most of the body's cholesterol. These particles, called "bad" cholesterol, are partially responsible for forming plaque along blood vessel walls. The more LDLs you have, the greater your risk of getting coronary artery disease—or a heart attack.
- High Density Lipoproteins (HDLs)—HDLs are known as "good" cholesterol. They are the protective counterparts to LDLs. HDLs contain a high proportion of protein, and their function is to scour the bloodstream, collecting excess cholesterol and transporting it back to the liver. The liver removes the cholesterol from the body. High levels of HDL cholesterol reduce the risk of heart disease and stroke.
Cholesterol and Heart Disease
Problems occur when the levels of cholesterol in the blood get too high.
Increased levels of cholesterol in the blood can contribute to atherosclerosis. This is the gradual build-up of plaque along the walls of your arteries. Over time, this build-up can narrow the artery and stiffen the arterial wall. If the plaque is severe enough, it can block blood flow. If this blockage occurs in the heart, it can cause a heart attack. In the brain, it can cause a stroke.
Part of the plaque can also break off and be released into the blood flow. Once released, clots can travel through the bloodstream through smaller and smaller vessels until they either dissolve or reach a point where they cannot squeeze through, causing a blockage.
High cholesterol is one of many risk factors for developing heart disease. Your actual risk of heart disease will depend on the combination of risk factors. Some risk factors like cholesterol level can be modified, while others like age can not be changed. The full list of risk factors for heart disease includes:
- People over age 55
- Family history of heart disease or high cholesterol
The more risk factors you have, the greater your chances of developing heart disease.
What Is Your Risk?
Cholesterol levels can be measured with a simple blood test. What is too high for you will depend on the number of heart disease risk factors that you have. The table below are recommended levels for people with no known heart disease risk factors.
If you have other risk factors for heart disease such as diabetes, your doctor may recommend lower target cholesterol levels. Discuss your risk factors and cholesterol goals with your doctor.
Ways to Lower Cholesterol
Fortunately there are some effective ways to lower and manage your cholesterol levels.
Lifestyle changes are often an effective way to lower cholesterol and reduce your risk of heart disease. This can include regular exercise, a healthy diet, not smoking, and maintaining a healthy weight. There are also cholesterol-lowering medications if you need them.
Make sure to have your cholesterol levels tested regularly (at least once every 5 years). If you are concerned about your cholesterol levels, talk to your doctor to create a plan that is right for you.
- Reviewer: Michael Woods, MD
- Review Date: 09/2014 -
- Update Date: 10/14/2014 -