What are triglycerides?
Triglycerides are the chemical form in which most fat exists in food as well as in the body. They're also present in blood plasma and, in association with cholesterol, form the plasma lipids. Triglycerides in plasma are derived from fats eaten in foods or made in the body from other energy sources like carbohydrates. Calories ingested in a meal and not used immediately by tissues are converted to triglycerides and transported to fat cells to be stored. Hormones regulate the release of triglycerides from fat tissue so they meet the body's needs for energy between meals.
How is an excess of triglycerides harmful?
Excess triglycerides in plasma is called hypertriglyceridemia. It's linked to the occurrence of coronary artery disease in some people. Elevated triglycerides may be a consequence of other disease, such as untreated diabetes mellitus. Like cholesterol, increases in triglyceride levels can be detected by plasma measurements. These measurements should be made after an overnight food and alcohol fast.
| The National Cholesterol Education Program guidelines for triglycerides are: | |
|---|---|
| Normal | Less than 150 mg/dL |
| Borderline-high | 150 to 199 mg/dL |
| High | 200 to 499 mg/dL |
| Very high | 500 mg/dL or higher |
| These are based on fasting plasma triglyceride levels. | |
What is cholesterol?
Cholesterol is a soft, waxy substance found among the lipids (fats) in the bloodstream and in all your body's cells. It's an important part of a healthy body because it's used to form cell membranes, some hormones and is needed for other functions. But a high level of cholesterol in the blood - hypercholesterolemia - is a major risk factor for coronary heart disease, which leads to heart attack. Cholesterol and other fats can't dissolve in the blood. They have to be transported to and from the cells by special carriers called lipoproteins. There are several kinds, but the ones to focus on are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).
What is LDL cholesterol?
Low-density lipoprotein is the major cholesterol carrier in the blood. If too much LDL cholesterol circulates in the blood, it can slowly build up in the walls of the arteries feeding the heart and brain. Together with other substances it can form plaque, a thick, hard deposit that can clog those arteries. This condition is known as atherosclerosis. A clot (thrombus) that forms near this plaque can block the blood flow to part of the heart muscle and cause a heart attack. If a clot blocks the blood flow to part of the brain, a stroke results. A high level of LDL cholesterol (160 mg/dL and above) reflects an increased risk of heart disease. If you have heart disease, your LDL cholesterol should be less than 100 mg/dL. That's why LDL cholesterol is called "bad" cholesterol. Lower levels of LDL cholesterol reflect a lower risk of heart disease.
What is HDL cholesterol?
About one-third to one-fourth of blood cholesterol is carried by HDL. Medical experts think HDL tends to carry cholesterol away from the arteries and back to the liver, where it's passed from the body. Some experts believe HDL removes excess cholesterol from plaques and thus slows their growth. HDL cholesterol is known as "good" cholesterol because a high HDL level seems to protect against heart attack. The opposite is also true: a low HDL level (less than 40 mg/dL in men; less than 50 mg/dL in women) indicates a greater risk. A low HDL cholesterol level also may raise stroke risk.
What is Lp(a) cholesterol?
Lp(a) is a genetic variation of plasma LDL. A high level of Lp(a) is an important risk factor for developing atherosclerosis prematurely. How an increased Lp(a) contributes to heart disease isn't clear. The lesions in artery walls contain substances that may interact with Lp(a), leading to the buildup of fatty deposits.
What about Total Blood Cholesterol and my Test Results?
Cholesterol plays a major role in a person's heart health. High blood cholesterol is a major risk factor for coronary heart disease and stroke. That's why it's important for all people to know their cholesterol level. They should also learn about their other risk factors for heart disease and stroke. Total blood cholesterol is the most common measurement of blood cholesterol. It's the number you receive as test results. Cholesterol is measured in milligrams per deciliter of blood (mg/dL). Blood cholesterol for adults is classified by levels. Your healthcare provider must interpret your cholesterol numbers based on other risk factors such as age, gender, family history, race, smoking, high blood pressure, physical inactivity, obesity and diabetes. Researchers have established healthy ranges for each of these. They're given in the lists below. If a fasting lipoprotein profile (i.e., blood test done after a 9-12-hour fast without food, liquids or pills) isn't possible, the values for total cholesterol and HDL cholesterol are acceptable.
| Initial classification based on total cholesterol and HDL cholesterol |
|---|
| Total Cholesterol Level | Category |
|---|---|
| Less than 200 mg/dL | Desirable level that puts you at lower risk for coronary heart disease. A cholesterol level of 200 mg/dL or higher raises your risk. |
| 200 to 239 mg/dL | Borderline high |
| 240 mg/dL and above | High blood cholesterol. A person with this level has more than twice the risk of coronary heart disease as someone whose cholesterol is below 200 mg/dL. |
| HDL Cholesterol Level | Category |
|---|---|
| Less than 40 mg/dL (for men) Less than 50 mg/dL (for women) |
Low HDL cholesterol. A major risk factor for heart disease. |
| 60 mg/dL and above | High HDL cholesterol. An HDL of 60 mg/dL and above is considered protective against heart disease. |
If your total cholesterol is 200 mg/dL or more, or your HDL cholesterol is less than 40 mg/dL (for men) and less than 50 mg/dL (for women), you need to have a lipoprotein profile done to determine your LDL cholesterol and triglyceride levels. If your cholesterol is high or you have other risk factors, your healthcare provider will likely want to monitor your cholesterol more closely. Follow your provider's advice about how often to have your cholesterol tested. He or she will set appropriate management goals based on your LDL cholesterol level and other risk factors.
| LDL Cholesterol Level | Category |
|---|---|
| Less than 100 mg/dL | Optimal |
| 100 to 129 mg/dL | Near or above optimal |
| 130 to 159 mg/dL | Borderline high |
| 160 to 189 mg/dL | High |
| 190 mg/dL and above | Very high |
Your LDL cholesterol goal depends on how many other risk factors you have.
- If you don't have coronary heart disease or diabetes and have one or no risk factors, your LDL goal is less than 160 mg/dL.
- If you don't have coronary heart disease or diabetes and have two or more risk factors, your LDL goal is less than 130 mg/dL.
- If you do have coronary heart disease or diabetes, your LDL goal is less than 100 mg/dL.
| Triglyceride Level | Category |
|---|---|
| Less than 150 mg/dL | Normal |
| 150-199 mg/dL | Borderline high |
| 200-499 mg/dL | High |
| 500 mg/dL and above | Very high |
On the whole, Americans should reduce the amount of saturated fat, trans fat, cholesterol and total fat in their diet. If you have high blood cholesterol, it's very important to control high blood pressure, avoid tobacco smoke, eat a healthy diet, get regular physical act ivity, maintain a healthy weight, and control or delay the onset of diabetes. Taking these steps will help lower your risk of heart disease and stroke. If you still need drugs to reduce your blood cholesterol, a healthy diet and active lifestyle will help lower your cholesterol and improve your overall cardiovascular health.
