Cholesterol is a fatty, wax-like substance that circulates throughout the bloodstream. Your body manufactures some of it, and the rest comes from your diet. Cholesterol is an essential building block of every cell in the human body. High cholesterol—also known as hypercholesterolemia—is a lipid disorder that can significantly raise the risk of heart disease. When the body has more than it can handle, excess cholesterol can build up and clog the arteries, cutting off the blood supply to the heart. That’s why it’s important to have your cholesterol tested regularly and to keep your levels down. Eating a heart-healthy diet and exercising regularly can help prevent high cholesterol.
There are several types of cholesterol in the body. When you have high cholesterol, one or all of the types may be within an unhealthy, abnormal range. At the doctor’s office, your physician may talk to you about your total cholesterol, or he may break it down into the different types: low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides. The term “high cholesterol” is actually a bit of a misnomer because, while it’s true we want to keep our LDL and triglycerides down, we should strive to push our HDL up. Low levels of HDL are considered abnormal and are a risk factor for heart disease.
High-Density Lipoprotein is the so-called “good” cholesterol that may help protect against heart disease. (You can remember that by thinking “H” is for healthy.) The higher your HDL, the better. That’s because HDL cholesterol sweeps excess LDL cholesterol (the “bad" artery-clogging kind) out of the body. The clinical term for having abnormally low levels of HDL is hypoalphalipoproteinemia (HA). Although there is no cut-off number that diagnoses HA, low HDL levels (less than 40 mg/dL for men and less than 50 mg/dL for women) are associated with a greater risk of heart disease. To protect against heart disease, the American Heart Association recommends that men and women should keep their HDL levels above 60mg/dL.
Low-Density Lipoprotein (LDL) is the “bad” cholesterol that contributes to atherosclerosis, which is the buildup of plaque along the arterial walls. (You can remember this by thinking “L” for lousy.) Atherosclerosis can cause your arteries— which transport blood, oxygen, and nutrients—to harden or rupture and lead to blockages, strokes, and heart attacks. That’s why high levels of LDL cholesterol are a major risk factor for heart disease. Guidelines state that people with no risk of heart disease should aim for an LDL score below 130. However, some medical experts believe that number is too high.
The American Heart Association and the National Heart, Lung, and Blood Institute both state that everyone’s LDL should be below 100 for optimal health. People who are at high risk of heart disease should keep their LDL below 100, and people who have heart disease or are at an extremely high risk of heart disease should aim to keep their LDL below 70.
This is the sum of your HDL and LDL scores. In general, you want to strive to keep your total cholesterol under 200 mg/dL. Although some physicians will only give you this result after you get your cholesterol tested, it’s a good idea to ask them to break it down for you so you know if your HDL is as high as you’d like and your LDL is as low as you’d like. A total cholesterol score of 200 to 239 mg/dL is considered borderline high-risk, while a score of 240 mg/dL or more is in the high-risk category. According to the American Heart Association, nearly half of all American adults have a total cholesterol score above 200 mg/dL.
Triglycerides are another type of lipid (fat) found in the bloodstream. Extra calories that your body doesn’t use get stored as triglycerides. As such, frequently overeating and being overweight may lead to elevated triglycerides. High triglyceride levels, known as hypertriglyceridemia, usually go hand-in-hand with high levels of “bad” LDL and low levels of “good” HDL. A triglyceride level below 150 mg/dL is considered normal. Between 150 and 200 is borderline-high; 200 to 499 is high; and more than 500 is very high.