Cholesterol

medical animation:





Alternative names

Diet - cholesterol
Definition

Cholesterol is a soft, waxy substance found in all parts of the body. This includes the nervous system, skin, muscle, liver, intestines, and heart. It is made by the body and also obtained from animal products in the diet.

Function

Cholesterol is manufactured in the liver for normal body functions, including the production of hormones, bile acid, and vitamin D. It is transported in the blood to be used by all parts of the body.

Food Sources

In foods, cholesterol is found in eggs, dairy products, meat, and poultry. Egg yolks and organ meats (liver, kidney, sweetbread, and brain) are high in cholesterol. Fish generally contains less cholesterol than other meats, but some shellfish are high in cholesterol.

Foods of plant origin (vegetables, fruits, grains, cereals, nuts, and seeds) contain no cholesterol.

Fat content is not a good measure of cholesterol content. For example, liver and other organ meats are low in fat, but very high in cholesterol.

Side Effects

In general, you have a greater risk of developing heart disease or atherosclerosis as your level of blood cholesterol increases.

Recommendations

More than half of the adult population has blood cholesterol levels higher than the desirable range. High cholesterol levels often begin in childhood. Some children may be at higher risk due to a family history of high cholesterol.

In general, you want your total cholesterol to be less than 200 milligrams per deciliter (mg/dl), because that level carries the least risk of heart disease. When the level is above 200 mg/dl, the risk for heart disease increases.

You should also know your levels of high density lipoprotein (HDL, also known as the "good cholesterol") and low density lipoprotein (LDL, or "bad cholesterol"). Talk to your health care provider about what your cholesterol levels mean.

To lower high cholesterol levels:

Limit total fat intake to 25 - 35% of total daily calories. Less than 7% of daily calories should be from saturated fat, not more than 10% should be from polyunsaturated fat, and not more than 20% from monounsaturated fat.
Eat less than 200 mg of dietary cholesterol per day.
Get more fiber in your diet.
Lose weight.
Increase physical activity.
The recommendations for children's diets are similar to those of adults. It is very important that children get enough calories to support their growth and activity level, and that the child achieve and maintain a desirable body weight

The following two sample menus provide examples of an average American diet and a low-fat diet.

AVERAGE AMERICAN DIET

Breakfast
1 egg scrambled in 1 teaspoon of butter
2 slices of white toast
1 teaspoon of butter
1/2 cup of apple juice
Snack
1 cake donut
Lunch
1 ham and cheese sandwich (2 ounces of meat, 1 ounce of cheese)
white bread
1 teaspoon of mayonnaise
1-ounce bag potato chips
12-ounce soft drink
2 chocolate chip cookies
Snack
8 wheat thins
Dinner
3 ounces of broiled sirloin
1 medium baked potato
1 tablespoon of sour cream
1 teaspoon of butter
1/2 cup of peas, 1/2 teaspoon of butter
Totals: 2,000 Calories, 84 grams fat, 34 grams saturated fat, 425 milligrams cholesterol. The diet is 38% total fat, 15% saturated fat.

LOW FAT DIET

Breakfast
1 cup of toasted oat ring cereal
1 cup of skim milk
1 slice of whole-wheat bread
1 banana
Snack
1 cinnamon raisin bagel, 1/2 ounce light cream cheese
Lunch
turkey sandwich (3 ounces of turkey)
rye bread
lettuce
1 orange
3 fig newtons
1 cup skim milk
Snack
non fat yogurt with fruit
Dinner
3 ounces of broiled chicken breast
1 medium baked potato
1 tablespoon of nonfat yogurt
1/2 cup of broccoli
1 dinner roll
1 cup skim milk
Totals: 2,000 Calories, 38g fat, 9.5g saturated fat, 91mg cholesterol. The diet is 17% fat, 4% saturated fat.

COMPARISON

For the same number of calories, a low-fat diet provides 190 mg of cholesterol, compared to 510 mg of cholesterol for an average American diet.

Because fat is high in calories, the low-fat diet actually has more food than the typical American diet.

CHILDREN

The low-fat diet example is too low in fat for small children to promote good growth. In addition, it may be difficult for them to consume such a large volume of food. Children should have a diet that is closer to 30% of calories from fat. Lower-fat diets may be appropriate in some children. Ask your doctor what is best for your child.



Cholesterol

AHA Scientific Position
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 cholesterol and diet?

People get cholesterol in two ways. The body — mainly the liver — produces varying amounts, usually about 1,000 milligrams a day. Foods also can contain cholesterol. Foods from animals (especially egg yolks, meat, poultry, fish, seafood and whole-milk dairy products) contain it. Foods from plants (fruits, vegetables, grains, nuts and seeds) don't contain cholesterol.

Typically the body makes all the cholesterol it needs, so people don't need to consume it. Saturated fatty acids are the main culprit in raising blood cholesterol, which increases your risk of heart disease. Trans fats also raise blood cholesterol. But dietary cholesterol also plays a part. The average American man consumes about 337 milligrams of cholesterol a day; the average woman, 217 milligrams.

Some of the excess dietary cholesterol is removed from the body through the liver. Still, the American Heart Association recommends that you limit your average daily cholesterol intake to less than 300 milligrams. If you have heart disease, limit your daily intake to less than 200 milligrams. Still, everyone should remember that by keeping their dietary intake of saturated fats low, they can significantly lower their dietary cholesterol intake. Foods high in saturated fat generally contain substantial amounts of dietary cholesterol.

People with severe high blood cholesterol levels may need an even greater reduction. Since cholesterol is in all foods from animal sources, care must be taken to eat no more than six ounces of lean meat, fish and poultry per day and to use fat-free and low-fat dairy products. High-quality proteins from vegetable sources such as beans are good substitutes for animal sources of protein.

How does physical activity affect cholesterol?

Regular physical activity increases HDL cholesterol in some people. A higher HDL cholesterol is linked with a lower risk of heart disease. Physical activity can also help control weight, diabetes and high blood pressure. Aerobic physical activity raises your heart and breathing rates. Regular moderate to intense physical activity such as brisk walking, jogging and swimming also condition your heart and lungs.

Physical inactivity is a major risk factor for heart disease. Even moderate-intensity activities, if done daily, help reduce your risk. Examples are walking for pleasure, gardening, yard work, housework, dancing and prescribed home exercise.

How does tobacco smoke affect cholesterol?

Tobacco smoke is one of the six major risk factors of heart disease that you can change or treat. Smoking lowers HDL cholesterol levels and increases the tendency for blood to clot.

How does alcohol affect cholesterol?

In some studies, moderate use of alcohol is linked with higher HDL cholesterol levels. However, because of other risks, the benefit isn't great enough to recommend drinking alcohol if you don't do so already.

If you drink, do so in moderation. People who consume moderate amounts of alcohol (an average of one to two drinks per day for men and one drink per day for women) have a lower risk of heart disease than nondrinkers. However, increased consumption of alcohol brings other health dangers, such as alcoholism, high blood pressure, obesity, stroke, cancer, suicide, etc. Given these and other risks, the American Heart Association cautions people against increasing their alcohol intake or starting to drink if they don't already do so. Consult your doctor for advice on consuming alcohol in moderation.