About Cholesterol

You get cholesterol in two ways. Your body makes some of it, and the rest comes from cholesterol in animal products that you eat, such as meats, poultry, fish, eggs, butter, cheese and whole milk. Food from plants — like fruits, vegetables and cereals — doesn't have cholesterol. Some foods that don't contain animal products may contain trans fats, which cause your body to make more cholesterol. Foods with saturated fats also cause the body to make more cholesterol.

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 two kinds that you need to know about. Low-density lipoprotein, or LDL, is known as the "bad" cholesterol. Too much LDL cholesterol can clog your arteries, increasing your risk of heart attack and stroke. High-density lipoprotein, or HDL, is known as the "good" cholesterol. Your body makes HDL cholesterol for your protection. It carries cholesterol away from your arteries. Studies suggest that high levels of HDL cholesterol reduce your risk of heart attack.

What's the Difference Between LDL and HDL Cholesterol?

Why is LDL cholesterol considered "bad"?
When too much LDL cholesterol circulates in the blood, it can slowly build up in the inner walls of the arteries that feed 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. If a clot forms and blocks a narrowed artery, it can cause a heart attack or stroke. The levels of HDL cholesterol and LDL cholesterol in the blood are measured to evaluate the risk of having a heart attack. LDL cholesterol of less than 100 mg/dL is the optimal level.  Less than 130 mg/dL is near optimal for most people.  A high LDL level (more than 160 mg/dL or 130 mg/dL or above if you have two or more risk factors for cardiovascular disease) reflects an increased risk of heart disease. That's why LDL cholesterol is often called "bad" cholesterol. 

Why is HDL cholesterol considered "good"?
About one-third to one-fourth of blood cholesterol is carried by high-density lipoprotein (HDL). HDL cholesterol is known as the "good" cholesterol because a high level of it seems to protect against heart attack. (Low HDL cholesterol levels [less than 40 mg/dL] increase the risk for heart disease.) Medical experts think that HDL tends to carry cholesterol away from the arteries and back to the liver, where it's passed from the body. Some experts believe that HDL removes excess cholesterol from plaque in arteries, thus slowing the buildup.

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 fatty deposits in arteries prematurely. The way an increased Lp(a) contributes to disease isn’t understood. The lesions in artery walls contain substances that may interact with Lp(a), leading to the buildup of fatty deposits.

The triglyceride connection
Triglyceride is a form of fat. It comes from food and is also made in your body. People with high triglycerides often have a high total cholesterol, a high LDL cholesterol and a low HDL cholesterol level. Many people with heart disease also have high triglyceride levels. People with diabetes or who are obese are also likely to have high triglycerides. Triglyceride levels of less than 150 mg/dL are normal; levels from 150–199 are borderline high.  Levels that are borderline high or high (200–499 mg/dL) may need treatment in some people. Triglyceride levels of 500 mg/dL or above are very high. Doctors need to treat high triglycerides in people who also have high LDL cholesterol levels.

What Are Healthy Levels of Cholesterol?
Your total blood cholesterol will fall into one of these categories:

Desirable — Less than 200 mg/dL
Borderline high risk — 200–239 mg/dL
High risk — 240 mg/dL and over

Here is some more explanation about each of these categories.

Desirable
If your total cholesterol is less than 200 mg/dL, your heart attack risk is relatively low, unless you have other risk factors. Even with a low risk, it's still smart to eat foods low in saturated fat, trans fat and cholesterol, and also get plenty of physical activity. Have your cholesterol levels measured every five years — or more often if you're a man over 45 or a woman over 55.

Borderline high risk
People whose cholesterol level is from 200 to 239 mg/dL are borderline high risk. About a third of American adults are in this (borderline) group; almost half of adults have total cholesterol levels below 200 mg/dL.

Have your cholesterol and HDL rechecked in one to two years if:

You should also lower your intake of foods high in saturated fat and cholesterol to reduce your blood cholesterol level to below 200 mg/dL. Your doctor may order another blood test to measure your LDL cholesterol. Ask your doctor to discuss your LDL cholesterol with you. Even if your total cholesterol is between 200 and 239 mg/dL, you may not be at high risk for a heart attack. Some people — such as women before menopause and young, active men who have no other risk factors — may have high HDL cholesterol and desirable LDL levels. Ask your doctor to interpret your results. Everyone's case is different.

High risk
If your total cholesterol level is 240 or more, it's definitely high. Your risk of heart attack and stroke is greater. In general, people who have a total cholesterol level of 240 mg/dL have twice the risk of coronary heart disease as people whose cholesterol level is 200 mg/dL.

You need more tests. Ask your doctor for advice. About 20 percent of the U.S. population has high blood cholesterol levels.

Your LDL cholesterol level
Your LDL cholesterol level greatly affects your risk of heart attack and stroke. The lower your LDL cholesterol, the lower your risk. In fact, it’s a better gauge of risk than total blood cholesterol. Your LDL cholesterol will fall into one of these categories:

The key point to remember is, the lower your LDL cholesterol, the lower your risk. Your doctor may prescribe a diet low in saturated fat and cholesterol, regular exercise and a weight management program if you're overweight. If you can't lower your cholesterol with these efforts, medications may also be prescribed to lower your LDL cholesterol. Check these categories and the goals for treatment that can lower your risk of heart attack.

Your HDL cholesterol level
In the average man, HDL cholesterol levels range from 40 to 50 mg/dL. In the average woman, they range from 50 to 60 mg/dL. HDL cholesterol that's less than 40 mg/dL is low. Low HDL cholesterol puts you at high risk for heart disease. Smoking, being overweight and being sedentary can all result in lower HDL cholesterol. If you have low HDL cholesterol, you can help raise it by:

People with high blood triglycerides usually have lower HDL cholesterol and a higher risk of heart attack and stroke. Progesterone, anabolic steroids and male sex hormones (testosterone) also lower HDL cholesterol levels. Female sex hormones raise HDL cholesterol levels.

Cholesterol ratio
Total blood cholesterol is the most common measurement of blood cholesterol. It's the number you normally receive as test results. Cholesterol is measured in milligrams per deciliter of blood (mg/dL). Knowing your total blood cholesterol level is an important first step in determining your risk for heart disease. However, a critical second step is knowing your HDL or "good" cholesterol level.

Some physicians and cholesterol technicians use the ratio of total cholesterol to HDL cholesterol in place of the total blood cholesterol. The American Heart Association recommends that the absolute numbers for total blood cholesterol and HDL cholesterol levels be used. They're more useful to the physician than the cholesterol ratio in determining the appropriate treatment for patients.

The ratio is obtained by dividing the HDL cholesterol level into the total cholesterol. For example, if a person has a total cholesterol of 200 mg/dL and an HDL cholesterol level of 50 mg/dL, the ratio would be stated as 4:1. The goal is to keep the ratio below 5:1; the optimum ratio is 3.5:1.

Your triglyceride level
Your triglyceride level will fall into one of these categories:

Many people with high triglycerides have underlying diseases or genetic disorders. If this is true for you, the main therapy is to change your lifestyle. This includes controlling your weight, eating foods low in saturated fat, trans fat and cholesterol, exercising regularly, not smoking and, in some cases, drinking less alcohol. People with high triglycerides may also need to limit their intake of carbohydrates to no more than 45–50 percent of total calories. The reason for this is that carbohydrates raise triglycerides in some people and lower HDL cholesterol. Use products with monounsaturated and polyunsaturated fats.

Following a Healthy Eating Plan

The best way to help lower your blood cholesterol level is to eat less saturated fat and cholesterol, control your weight and walk or do another physical activity for at least 30 minutes each day.

Know your fats
Knowing which fats raise LDL cholesterol and which ones don't is the first step in lowering your risk of heart disease. Saturated fat, trans -fatty acids and dietary cholesterol raise blood cholesterol. Monounsaturated fats and polyunsaturated fats don't. Some studies suggest they might even help lower LDL cholesterol slightly when eaten as part of a low-saturated-fat diet.

Saturated fats
Saturated fat is the main dietary cause of high blood cholesterol. The American Heart Association recommends that you limit your saturated fat intake to 7–10 percent of total calories (or less) each day. If you have coronary heart disease or your LDL cholesterol level is 100 mg/dL or greater, your doctor should recommend the Therapeutic Lifestyle Change (TLC) Diet. It recommends 25–35 percent of calories from fat, with less than 7 percent coming from saturated fat. Cholesterol is limited to less than 200 milligrams a day.

Saturated fat is found mostly in foods from animals and some plants.

Foods from animals  — These include beef, beef fat, veal, lamb, pork, lard, poultry fat, butter, cream, milk, cheeses and other dairy products made from whole milk. These foods also contain dietary cholesterol.

Foods from plants  — These include coconut oil, palm oil and palm kernel oil (often called tropical oils), and cocoa butter.

Hydrogenated fats
During food processing, fats may undergo a chemical process called hydrogenation. This is common in margarine and shortening. These fats also raise blood cholesterol. Use hydrogenated fats only if they contain no more than two grams of saturated fat per tablespoon. The saturated fat content of most margarines and spreads is printed on the package or Nutrition Facts label.

Polyunsaturated and monounsaturated fats  — Polyunsaturated and monounsaturated fats are the two unsaturated fats. They're found primarily in oils from plants.

Polyunsaturated fats  — These include safflower, sesame and sunflower seeds, corn and soybeans, many nuts and seeds, and their oils.

Monounsaturated fats  — These include canola, olive and peanut oils, and avocados.

Both polyunsaturated and monounsaturated fats may help lower your blood cholesterol level when you use them in place of saturated fats in your diet. But a moderate intake of all types of fat is best. Use polyunsaturated or monounsaturated oils — and margarines and spreads made from them — in limited amounts. This is recommended in place of using fats with a high saturated fat content, such as butter, lard or hydrogenated shortenings.

Trans-fatty acids
Unsaturated fatty acids can be in one of two shapes — "cis" and "trans." These terms refer to the physical positioning of hydrogen atoms around the carbon chain. The cis form is more common than the trans form. Trans-fatty acids (TFA) are found in small amounts in various animal products such as beef, pork, lamb and the butterfat in butter and milk. TFA are also formed during the process of hydrogenation, making margarine, shortening, cooking oils and the foods made from them a major source of TFA in the American diet. Partially hydrogenated vegetable oils provide about three-fourths of the TFA in the U.S. diet.

To make foods that will stay fresh on the shelf or to get a solid fat product, such as margarine, food manufacturers hydrogenate polyunsaturated oils. "Hydrogenate" means to add hydrogen. When unsaturated fatty acids are hydrogenated, some of the hydrogen atoms are added on opposite sides of the molecule to the already attached hydrogen. Cis double bonds convert to trans double bonds, and the fatty acids become saturated.

How are trans-fatty acids harmful?
In clinical studies, TFA or hydrogenated fats tend to raise total blood cholesterol levels. Some scientists believe they raise cholesterol levels more than saturated fats. TFA also tend to raise LDL ("bad") cholesterol and lower HDL ("good") cholesterol when used instead of cis fatty acids or natural oils. These changes may increase the risk of heart disease.

Because there are no standard methods, it's difficult to estimate the TFA content of food items. It's also difficult to estimate intake, especially long-term intake. The four most important sources of TFA in one large group of women studied included margarine; beef, pork or lamb as the main dish; cookies (biscuits); and white bread.

Recently the FDA passed a regulation requiring trans fat to be listed on the nutrition label by January 2006. Although changes in labeling are important, they aren't enough. Many fast foods contain high levels of TFA. There are no labeling regulations for fast food, and it can even be advertised as cholesterol-free and cooked in vegetable oil. Eating one doughnut at breakfast (3.2 g of TFA) and a large order of french fries at lunch (6.8 g of TFA) add 10 g of TFA to one's diet, so the lack of regulations for labeling restaurant foods can be harmful to your health.

Is butter better than margarine?
Recent studies on the potential cholesterol-raising effects of TFA have raised public concern about the use of margarine and whether other options, including butter, might be a better choice. Some stick margarines contribute more TFA than unhydrogenated oils or other fats.

Because butter is rich in both saturated fat and cholesterol, it's potentially a highly atherogenic food (a food that causes the arteries to be blocked). Most margarine is made from vegetable fat and provides no dietary cholesterol. The more liquid the margarine, i.e., tub or liquid forms, the less hydrogenated it is and the less TFA it contains.

What can I do to regulate my intake of trans-fatty acids?
The American Heart Association's Nutrition Committee strongly advises that healthy Americans over age 2 limit their intake of saturated fat to 7–10 percent of total calories. Individuals should adjust total fat intake to meet their caloric needs. People who are overweight or obese should limit their total fat intake to no more than 30 percent of total calories.

On the basis of current data, the American Heart Association recommends that consumers follow these tips:

Common Misconceptions About Cholesterol

1.     Using margarine instead of butter will help lower my cholesterol.

Both margarine and butter are high in fat, so use both in moderation. From a dietary perspective, the major factor affecting blood cholesterol is how much saturated fat is in the food. Reducing your intake of saturated fat is key to helping control cholesterol. Most soft or liquid margarines have less saturated fat and are preferable to the stick forms for a heart-healthy diet. It's best to select trans fat-free margarines. However, eat all fatty foods in moderation.

2.     Thin people don’t have to worry about high cholesterol.

Overweight people are more likely to have high cholesterol from eating too many fatty foods, but thin people should also have their cholesterol checked regularly. Often people who don’t gain weight easily are less aware of how much saturated fat they eat. Nobody can “eat anything they want” and stay heart healthy. Have your cholesterol checked regularly regardless of your weight, exercise habits and diet.

3.     My doctor hasn’t said anything about my cholesterol, so I don’t have to worry.

Unfortunately, not all physicians are as proactive about healthy lifestyles as they should be. Your health is your responsibility. Make sure that you have a blood cholesterol test and learn how to interpret all the numbers, including HDL (good) cholesterol, LDL (bad) cholesterol and triglyceride levels. If you’re in a high or borderline-high range, discuss options with your physician. You may be able to control the levels by eating a diet lower in saturated fat and cholesterol, getting 30–60 minutes of physical activity on most days and quitting smoking. If lifestyle changes alone don’t work, your physician may prescribe a cholesterol-lowering medication.

4.     Since the nutrition label on my favorite food says there’s no cholesterol, I can be sure that it’s a “heart-healthy” choice.

Nutrition labels on food are very helpful when choosing heart-healthy foods, but you need to know what to look for. Many “low-cholesterol” foods contain high levels of saturated fat or trans fatty acids — both of which contribute to high blood cholesterol. Even foods that claim to be “low-fat” may have a higher fat content than expected. Look for the amount of saturated fat, total fat, cholesterol and total calories in a serving of the product. Also check how much a serving is. Often it’s smaller than you think. The first ingredient listed is the one used most in the product, so choose products where fats and oils appear later in the ingredient listing. The Food and Drug Administration will require foods to be labeled for trans fats by 2006. Many manufacturers have already begun doing this. Trans fats are found in variable amounts in most foods with partially hydrogenated oils such as baked goods, fried foods and some margarines and dairy products. 

5.     Since I started taking medication for my high cholesterol, I don’t have to worry about what I eat.

Unless your cholesterol is dangerously high, it's best to try to reduce it by changing your diet. Drug therapy is usually prescribed for those who — despite adequate dietary changes, regular physical activity and weight loss — still have elevated levels of cholesterol. Modern medications have come a long way in helping to control blood cholesterol levels, but making lifestyle changes along with taking medication is the best way to help prevent heart disease. Reducing the amount of saturated fat and cholesterol in your diet and getting 30–60 minutes of exercise on most or all days of the week is recommended, even if you’re taking cholesterol-lowering medication. It’s also very important to take your medication exactly as your doctor has instructed so it can work most efficiently

6.     I recently read that eggs aren’t so bad for your cholesterol after all, so I guess I can go back to having my two eggs for breakfast every morning.

One egg contains about 213 milligrams of dietary cholesterol. That’s a lot given that the daily recommended cholesterol limit is 300 milligrams. An egg a day can fit within heart-healthy guidelines only if cholesterol from other sources, such as meats, poultry and dairy products, is limited. For example, eating one egg for breakfast, drinking two cups of coffee with one tablespoon of half-and-half each, lunching on four ounces of lean turkey breast without skin and one tablespoon of mayonnaise, and having a 6-ounce serving of broiled, short loin porterhouse steak for dinner would account for about 510 mg of dietary cholesterol that day — nearly twice the recommended limit. If you’re going to eat an egg every morning, substitute vegetables for some of the meat, or drink your coffee without half-and-half.

7.     I’m a woman so I don’t have to worry. High cholesterol is a man’s problem.

Premenopausal women are usually protected from high LDL (bad) levels of cholesterol, because the female hormone estrogen tends to raise HDL (good) cholesterol levels. Postmenopausal women may find that even a heart-healthy diet and regular exercise aren’t enough to keep their cholesterol from rising. If you’re approaching menopause, it’s especially important to have your cholesterol checked and talk with your doctor about your options. Postmenopausal hormone therapy (PHT, formerly called hormone replacement therapy or HRT) is not recommended to prevent heart disease and may not be the best answer for every woman. To read the latest findings on PHT (HRT) and the American Heart Association’s position, use our search tool and type in hormone therapy.

8.     You don’t need to have your cholesterol checked until you reach middle age.

It’s a good idea to start having your cholesterol checked at an early age. Even children, especially those in families with a history of heart disease, can have high cholesterol levels. And evidence exists that these children are at greater risk for developing heart disease as adults. Lack of exercise, poor dietary habits and genetics can all affect a child’s cholesterol levels. You’re never too young to develop a heart-healthy lifestyle by eating foods low in saturated fats, getting 30–60 minutes of physical activity on most or all days, and avoiding tobacco products.