Cholesterol

Cholesterol is a waxy, fat-like material that is found in all parts of the body. It comes from two sources: our liver produces it, and we consume it in meat and dairy products.

Your body needs a little bit of cholesterol to work properly. But too much cholesterol can clog your arteries and lead to heart disease.

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.

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.

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.
• Lose weight.
• Increase physical activity.

HDL stands for high density lipoprotein, a form of "good" cholesterol. Lipoproteins are proteins in the blood that move cholesterol, triglycerides, and other fats, called lipids, to various parts of the body.

Studies of both men and women have shown that the higher your HDL, the lower your risk of coronary artery disease. This is why HDL is sometimes referred to as "good" cholesterol.

The main function of HDL is to help soak up excess cholesterol from the walls of blood vessels and carry it to the liver, where it breaks down and is removed from the body in the bile.

LDL ( low-density lipoprotein) is a type of cholesterol. Too much LDL in the blood can clog arteries.

LDL carries cholesterol to various tissues throughout the body. Too much LDL, commonly called "bad cholesterol," can lead to cardiovascular disease.

According to the National Heart, Lung, and Blood Institute, the lower your LDL, the lower your risk for heart disease or stroke.

A healthy LDL level is one that falls in the optimal or near-optimal range.

• Optimal: Less than 100 mg/dL (less than 70mg/dL for persons with a history of heart disease or those at very high risk for atherosclerotic disease)
• Near Optimal: 100-129 mg/dL
• Borderline High: 130-159 mg/dL
• High: 160-189 mg/dL
• Very High: 190 mg/dL and higher

High levels of LDL may be associated with:

• Increased risk of atherosclerotic heart disease
• Familial hyperlipoproteinemia

Lower-than-normal levels of LDL may be caused by:

• Malabsorption (inadequate absorption of nutrients from the intestinal tract)
• Malnutrition

The medical term for high blood cholesterol and triglycerides is lipid disorder. Such a disorder occurs when you have too many fatty substances in your blood. These substances include cholesterol and triglycerides.

A lipid disorder increases your risk for atherosclerosis and heart disease.

High cholesterol and other lipid disorders can be inherited (passed down through families) or associated with:

• Fatty diets
• Disease such as diabetes, hypothyroidism and kidney failure.
• Certain medications, including birth control pills, estrogen, corticosteroids, certain diuretics, and beta-blockers .
• Lifestyle factors, including inactivity and regular, excessive alcohol use.

If you smoke and also have high cholesterol you have an even greater risk for heart disease.

Lipid disorders are more common in men than women.

There are steps that everyone can take to improve their cholesterol levels, and help prevent heart disease and heart attack. Here are the most important ones:

• Choose foods low in saturated fat.
• Exercise regularly.
• Lose weight if you are overweight.
• Get routine health checkups and cholesterol screenings.

If lifestyle changes do not help or your cholesterol level remains very high, your doctor may recommend medication. There are several types of drugs available to help lower blood cholesterol levels, and they work in different ways. Some are better at lowering LDL cholesterol, some are good at lowering triglycerides, while others help raise HDL cholesterol.

The most commonly used drugs for treating high LDL cholesterol are called statins. Other drugs that may be used include bile acid sequestering resins, cholesterol absorption inhibitors, fibrates, and nicotinic acid (niacin).

If you are diagnosed with high cholesterol, you will probably need to continue lifestyle changes and drug treatment throughout your life. Periodic monitoring of your cholesterol blood levels is necessary. Reducing high cholesterol levels will slow the progression of atherosclerosis.

Possible complications of high cholesterol include:

• Atherosclerosis
• Coronary artery disease
• Stroke
• Heart attack or death

See diagram below -

Coronary artery disease

The coronary arteries supply blood to the heart muscle itself. Blood supply through these arteries is critical for the heart.

Coronary artery disease usually results from the build-up of fatty material and plaque, a condition called atherosclerosis. As the coronary arteries narrow, the flow of blood to the heart can slow or stop, causing chest pain (stable angina), shortness of breath, heart attack, or other symptoms.

To help prevent high cholesterol:

• Keep a healthy body weight
• Eat a well-balanced, low-fat diet