Cholesterol is a type of fat that occurs naturally in the body. It has both good and bad effects on the body. Your body uses cholesterol to make hormones and to build and maintain nerve cells. Cholesterol also produces vitamin D and acids that help to digest fat. However, when your body has too much cholesterol, deposits of fat called plaque form inside blood vessel walls. This causes the walls to thicken which means less blood can flow through the blood vessel. This condition is called atherosclerosis. When blood flow is reduced, it increases the risk for heart attack or stroke.
Most of the cholesterol in your blood is made by your liver from the fats, carbohydrates, and proteins you eat. You also get cholesterol by eating meat, eggs, and dairy products. Cholesterol travels through the body in the bloodstream. Since cholesterol is fatty, it doesn’t mix well with blood. To travel through the bloodstream, cholesterol attaches to a protein. This makes what is called a lipoprotein. There are different types of lipoproteins. Each has a different effect on your risk of atherosclerosis and heart disease. Low density lipoproteins (LDL) carry most of the cholesterol in the blood. LDL is the main cause of atherosclerosis. As a result, LDL is often called “bad cholesterol”.
High density lipoproteins (HDL) carry cholesterol in the blood back to the liver. The liver then removes the cholesterol from the body. High density lipoproteins help keep plaque from building up. HDL is called “good cholesterol”. Triglycerides also affect atherosclerosis. Triglycerides are fats that are found in nature and they are also made in the body. They come from foods high in fat, such as butter, sweets and starches. High triglyceride levels in the blood do not cause atherosclerosis. However, in some people, high triglyceride levels can cause atherosclerosis. Many people with high triglycerides may have other diseases, such as diabetes, or genetic disorders.