It may surprise you to know that cholesterol itself isn't bad. In fact, cholesterol is just one of the many substances created and used by our bodies to keep us healthy according to the American Heart Association. Some of the cholesterol we need is produced naturally (and can be affected by your family health history), while some of it comes from the food we eat. There are two types of cholesterol: “good” and “bad.” It’s important to understand the difference, and to know the levels of “good” and “bad” cholesterol in your blood. Too much of one type — or not enough of another — can put you at risk for coronary heart disease, heart attack or stroke.
According to the American Heart Association (AHA), 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). Here are descriptions of both types:
1.) 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 and your doctor may even set your goal to be less than 70 mg/dL. That's why LDL cholesterol is called "bad" cholesterol. Lower levels of LDL cholesterol reflect a lower risk of heart disease.
2.) 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.
According to WebMD, high cholesterol increases the risk of other conditions, depending on which blood vessels are narrowed or blocked. These diseases include: coronary heart disease, stroke and peripheral vascular disease. High cholesterol has also been linked to diabetes and high blood pressure. To prevent or manage these conditions, take steps to lower your cholesterol if it is elevated. The main risk associated with high cholesterol is coronary heart disease (CHD). Your blood cholesterol level has a lot to do with your chances of getting heart disease. If cholesterol is too high, it builds up in the walls of your arteries. Over time, this buildup (called plaque) causes hardening of the arteries (atherosclerosis). Atherosclerosis causes arteries to become narrowed, slowing blood flow to the heart. Reduced blood flow to the heart can result in angina (chest pain) or in a heart attack in cases when a blood vessel is blocked completely.
According to MedicineNet.com, the liver not only manufactures and secretes LDL cholesterol into the blood; it also removes LDL cholesterol from the blood. A high number of active LDL receptors on the liver surfaces is associated with the rapid removal of LDL cholesterol from the blood and low blood LDL cholesterol levels. A deficiency of LDL receptors is associated with high LDL cholesterol blood levels. Both heredity and diet have a significant influence on a person's LDL, HDL and total cholesterol levels. For example, familial hypercholesterolemia (FH) is a common inherited disorder whose victims have a diminished number or nonexistent LDL receptors on the surface of liver cells. People with this disorder also tend to develop atherosclerosis and heart attacks during early adulthood. Diets that are high in saturated fats and cholesterol raise the levels of LDL cholesterol in the blood. Fats are classified as saturated or unsaturated (according to their chemical structure). Saturated fats are derived primarily from meat and dairy products and can raise blood cholesterol levels. Some vegetable oils made from coconut, palm, and cocoa are also high in saturated fats. Most doctors now believe that the benefits of lowering LDL cholesterol include:
--Reducing or stopping the formation of new cholesterol plaques on the artery walls;
--Reducing existing cholesterol plaques on the artery walls;
--Widening narrowed arteries;
--Preventing the rupture of cholesterol plaques, which initiates blood clot formation;
--Decreasing the risk of heart attacks; and
--Decreasing the risk of strokes. The same measures that retard atherosclerosis in coronary arteries also benefit the carotid and cerebral arteries (arteries that deliver blood to the brain).
According to the NY Times, cholesterol helps the body produce hormones, bile acid, and vitamin D. Cholesterol moves through the bloodstream to be used by all parts of the body. 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. In general, your risk of developing heart disease or atherosclerosis goes up as your level of blood cholesterol increases.
People get cholesterol in two ways according to the American Heart Association. 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, shellfish and whole- and reduced-fat milk and 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 and trans 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.
More than half of the adult population has blood cholesterol levels higher than the desirable range according to the NY Times. High cholesterol levels often begin in childhood. Some children may be at higher risk due to a family history of high cholesterol. 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, no more than 10% should be from polyunsaturated fat, and no more than 20% from monounsaturated fat.
--Eat less than 200 mg of dietary cholesterol per day.
--Get more fiber in your diet.
--Increase physical activity or exercise. Physical activity can also help control weight, diabetes and high blood pressure. Aerobic physical activity raises your heart and breathing rates. Regular moderate-to-vigorous-intensity physical activity such as brisk walking, jogging and swimming also condition your heart and lungs. 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.
If you have high cholesterol, it may be necessary for you to make some lifestyle changes, according to FamilyDoctor.org (American Academy of Family Physicians). If you smoke, stop smoking. Exercise regularly. If you're overweight, losing just 5 to 10 pounds can help lower cholesterol levels. Make sure to eat plenty of fruits, vegetables, whole grains and fish- all of which promote heart health. Avoid saturated and trans fats, which can raise cholesterol levels. Also limit your overall cholesterol intake to less than 300 milligrams (200 milligrams if you have heart disease) per day. Depending on your risk factors, if healthy eating and exercise don't work after 6 months to 1 year, your doctor may suggest medication to lower your cholesterol level.
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