Cholesterol is a soft, waxy substance found among the lipids (fats) in the bloodstream and in all your body's cells. It's used to form cell membranes, some hormones and is needed for other functions. Your body makes all the cholesterol it needs. Until it's used, this cholesterol circulates in your blood. Cholesterol is part of a healthy body, but too much of it in your blood can be a problem. Eating foods that contain cholesterol (called dietary cholesterol) as well as foods high in saturated fats and trans-fats can raise blood cholesterol. The average American man consumes about 337 milligrams of cholesterol a day; the average woman, 217 milligrams.

Although some of the excess dietary cholesterol is removed from the body through the liver, the American Heart Association still recommends that the average daily cholesterol intake should be less than 300 milligrams. Someone with heart disease, should limit their daily intake to less than 200 milligrams. 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.

  • Dietary cholesterol is found only in foods from animals, such as meat, fish, poultry, egg yolks, butter, cheese and other dairy products made from whole milk. One large, whole egg contains about 213 mg of cholesterol. This is about 71 percent of the daily recommended limit for healthy people (less than 300 mg), and too much for those with certain risk factors. Extra-large and jumbo eggs contain more cholesterol than large eggs -- each provides up to 93 percent of the daily limit.
  • Saturated fats are found mostly in foods from animals, such as meat, lard, poultry fat, butter, cheeses and other whole-milk dairy products. Foods from some tropical plants also contain saturated fats, mainly coconut oil, palm oil, palm kernel oil and cocoa butter.
  • Trans-fats are saturated fats that have been processed to prolong their shelf life, including fast-food chains. Trans-fats are also found in commercial baked goods and stick margarines made with partially hydrogenated vegetable oils. The FDA doesn't require nutrition labels to show the amount of trans-fat in products. Look for the words "hydrogenated fat" or "partially hydrogenated vegetable oil" in the ingredient list.

Many scientists think saturated fats and trans-fats have a greater impact than dietary cholesterol in raising blood cholesterol levels.

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 (lip"o-PRO'te-inz). There are several kinds, but the ones to be most concerned about are low-density lipoprotein (LDL) and high-density lipoproteins (HDL).

What is LDL cholesterol or bad 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 (ath"er-o-skleh-RO'sis). 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 (130 mg/dL and above) reflects an increased risk of heart disease. That's why LDL cholesterol is often called "bad" cholesterol. Lower levels of LDL cholesterol reflect a lower risk of heart disease.

What is HDL cholesterol or good cholesterol?

About one-third to one-fourth of blood cholesterol is carried by high-density lipoprotein or 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) indicates a greater risk of heart disease. A low HDL cholesterol level also may increase the risk of stroke.

Eating soy (ie, tofu, which is made from soybeans) can help raise your level of high-density lipoprotein (HDL) Dishes that include soybeans, soy milk, soy flour, and textured soy protein are good places to start.