What is Cholesterol? Cholesterol is a waxy, fat-like substance that your liver makes. It is also found in some foods that come from animals. Cholesterol is found in all parts of your body. It plays a vital role in your body. It makes hormones, helps you digest food, and supports the workings of all the cells in your body. But your liver makes all the cholesterol that your body needs to do this. Lipoproteins and Cholesterol Cholesterol circulates in your blood stream. But it's fatty while your blood is watery. Just like oil and water, the two do not mix. As a result, cholesterol travels through your bloodstream in small packages called lipoproteins. The packages are made of fat (lipids) on the inside and proteins on the outside. Two kinds of lipoproteins carry cholesterol through your bloodstream. It's important to have healthy levels of both: - low-density lipoproteins (LDL)  - high-density lipoproteins (HDL).  low-density lipoproteins (LDL) high-density lipoproteins (HDL). What Does LDL Cholesterol Do? Low-density lipoproteins (LDL) carry cholesterol to all the cells in your body, including the arteries that supply blood to your heart. LDL cholesterol is sometimes called bad cholesterol because it can build up in the walls of your arteries. The higher the level of LDL cholesterol in your blood, the greater your chances of getting heart disease. What Does HDL Cholesterol Do? High-density lipoproteins (HDL) carry cholesterol away from the cells in your body. HDL cholesterol is sometimes called good cholesterol because it helps remove cholesterol from your artery walls. The liver then removes the cholesterol from your body. The higher your HDL cholesterol level, the lower your chances of getting heart disease. If Your Blood Cholesterol Is Too High Too much cholesterol in your blood is called high blood cholesterol. It can be serious. It increases your chances of having a heart attack or getting heart disease. When the cholesterol level in your blood is too high, it can build up in the walls of your arteries. This buildup of cholesterol is called plaque. Plaque Buildup Can Lead to - Artherosclerosis. Over time, the plaque can build up so much that it narrows your arteries. This is called atherosclerosis, or hardening of the arteries. It can slow down or block the flow of blood to your heart.  Artherosclerosis. Over time, the plaque can build up so much that it narrows your arteries. This is called atherosclerosis, or hardening of the arteries. It can slow down or block the flow of blood to your heart. - Coronary Heart Disease (CHD).  Artherosclerosis can occur in blood vessels anywhere in your body, including the ones that bring blood to your heart, called the coronary arteries. If plaque builds up in these arteries, the blood may not be able to bring enough oxygen to the heart muscle. This is called coronary heart disease (CHD).  Coronary Heart Disease (CHD).  Artherosclerosis can occur in blood vessels anywhere in your body, including the ones that bring blood to your heart, called the coronary arteries. If plaque builds up in these arteries, the blood may not be able to bring enough oxygen to the heart muscle. This is called coronary heart disease (CHD). - Angina.  The buildup of plaque can lead to chest pain called angina. Angina is a common symptom of CHD. It happens when the heart does not receive enough oxygen-rich blood from the lungs.  Angina.  The buildup of plaque can lead to chest pain called angina. Angina is a common symptom of CHD. It happens when the heart does not receive enough oxygen-rich blood from the lungs. - Heart Attack.  Some plaques have a thin covering, so they may rupture or break open. A blood clot can then form over the plaque. A clot can block the flow of blood through the artery. This blockage can cause a heart attack.  Heart Attack.  Some plaques have a thin covering, so they may rupture or break open. A blood clot can then form over the plaque. A clot can block the flow of blood through the artery. This blockage can cause a heart attack. Lowering Cholesterol Can Affect Plaque Lowering your cholesterol level reduces your chances of plaque rupturing and causing a heart attack. It may also slow down, reduce, or even stop plaque from building up. And it reduces your chances of dying from heart disease. High blood cholesterol itself does not cause symptoms, so many people don't know that they have it. It is important to find out what your cholesterol numbers are because if you have high blood cholesterol, lowering it reduces your chances of getting heart disease or having a heart attack.