How Does Cholesterol Relate to CVD?
Cholesterol is a type of fat, also known as a lipid, that circulates in your blood. It is naturally produced by your body and performs a number of important functions. For example, it helps build cell membranes; aids in the production of hormones, including estrogen and testosterone; and is critical to the process of fat absorption from food. Too much blood cholesterol can lead to artery damage and cardiovascular disease (CVD).
Cholesterol comes from two sources:
- The foods you eat, which provide 15% to 20%
- Your liver, which produces 80% to 85%
When your cholesterol levels are higher than normal, you’re considered to have “high cholesterol,” which is also known as “hyperlipidemia” or “hypercholesterolemia.”
Cholesterol is carried in the body by particles called lipoproteins — a type of cholesterol. There are three main components of cholesterol you should know about:
LDL (low-density lipoprotein): Sometimes called “bad” or “lousy” cholesterol, LDL carries most of the cholesterol in the blood to be stored away for future use. High levels of LDL cause cholesterol to build up on artery walls, leading to plaque formation.
HDL (high-density lipoprotein): Called “good” or “healthy” cholesterol, HDL carries cholesterol from the body to the liver, where it is eliminated. The more HDL you have in your blood, the better protected you are against the buildup of plaque in your arteries.
Triglycerides: This is the most common type of fat in your body. Triglycerides have a dual function, acting to both store and transport fat in the blood. When you eat excess calories (especially sugar and alcohol), they are stored as triglycerides. Similar to LDLs, excess triglycerides increase your risk for CVD.
Total cholesterol/HDL (TC/HDL) is a ratio used to measure your cardiovascular risk. TC/HDL is calculated by dividing your total cholesterol number by your total HDL cholesterol number.
How High Cholesterol Affects Your Cardiovascular Health
Cholesterol’s components — LDL, HDL, and triglycerides — work together for the healthy functioning of your body. However, both uncontrollable factors and lifestyle choices that maintain these fats at unhealthy target levels put you at risk of developing cardiovascular disease. When your total cholesterol is too high, each of the three components contribute to a range of adverse effects.
When LDL is too high
Too much LDL can lead to a buildup of cholesterol (plaques) on the walls of blood vessels, causing them to narrow or harden and restrict blood flow. This is known as atherosclerosis.
Narrowing of the blood vessels that lead to the heart can cause coronary artery disease, angina, and heart attack. Heart attacks result when plaques rupture, breaking away from the wall of a blood vessel, and block an artery. Narrowing of the blood vessels leading to the brain can cause stroke.
When HDL is too low
When your HDL cholesterol is too low, harmful cholesterol stays in the arteries instead of being transported to the liver and ultimately eliminated from the body.
When triglycerides are too high
High triglyceride levels are dangerous to your cardiovascular health because they increase the likelihood of hardening of the arteries, which raises the risk for heart disease, stroke, and heart attack.
Cholesterol levels generally are lower in younger women than younger men, but above the age of 65 they are much higher in women. If you have high levels of LDL cholesterol, your doctor may prescribe cholesterol-lowering medication, changes to your diet and exercise.