What Is Cholesterol?

Cholesterol is a soft, wax-like fatty substance (lipid) found in the human bloodstream and is critical to the normal function of cells within the human body. Cholesterol found in the blood originates from two main sources – dietary (through things we eat) and liver production.

  • Dietary cholesterol comes mainly from meat, fish, poultry and dairy products. Organ meats, liver for example, are very high in cholesterol content while plants contain no cholesterol.
  • The liver is capable of both removing and manufacturing cholesterol in the bloodstream. After eating meals the liver removes chylomicrons (metabolized balls of fat and cholesterol), while in between meals the liver manufactures and secretes cholesterol back into the blood circulation.

Cholesterol┬áneeds help to be┬átransported through the bloodstream, as it’s insoluble in blood. It makes it’s way through the circulatory system with the help of lipoprotein, which helps to carry fats around the body. There are two major types of lipoprotein – low density (LDL) and high density HDL) that transport cholesterol from and to the liver.

  • LDL (low density lipoprotein) is known as the bad cholesterol. LDL can slowly build up in the inner walls of the body’s arteries that feed the heart and brain and, together with other substances, can form plaque – a thick, hard deposit that can narrow the arteries and make them less flexible. This condition is known as atherosclerosis, and increase the likelyhood that plaque will break off and form a clot thereby blocking an artery – which can lead to angina (chest pain), a heart attack or stroke.
  • HDL (high density lipoprotein) is known as the good cholesterol as having high levels help to protect against atherosclerosis. HDL carries cholesterol out of the arteries and back to the liver, removing excess cholesterol from arterial plaque and slowing it’s buildup.

With that being said, having a high level of LDL cholesterol and a low level of HDL cholesterol is commonly known as high cholesterol (hypercholesterolemia), a risk factor for atherosclerosis, while having a low level of LDL cholesterol and high level of HDL cholesterol is ideal. Total cholesterol is the sum of LDL, HDL, VLDL (very low density), and IDL (intermediate density) cholesterol.

Testing for high cholesterol is usually done through a procedure, called a fasting lipoprotein profile, which is done after a 12 hour period without consumption of any foods, liquids or medication. It is recommended that everyone over the age of 20 have this test every 5 years. The test returns results based on 4 factors: total blood cholesterol, HDL, LDL, and triglyceride levels.

  • Maintaining a total blood cholesterol below 200 mg/dL is ideal, anything over 240 mg/dL is considered a high risk for heart disease.
  • With HDL cholesterol, the higher the better. Levels of 60 mg/dL or higher offers protection while anything under 40 mg/dL increases your risk of heart disease. Smoking cigarettes, being obese and/or inactive can all result in lower HDL cholesterol.
  • LDL is the best indicator of potential cardiovascular disease, lower is better. Levels less than 100 mg/dL are optimal while anything above 160 places you in the high risk category.
  • Finally triglycerides, a form of fat, where less than less than 150 mg/dL is ideal and anything over 200 mg/dL is considered a high risk. Having a high triglyceride level is usually attributed to being overweight, being physically inactive, smoking, excessive alcohol consumption and diets high in carbohydrates can contribute to a high triglyceride level.

Treatment for high cholesterol levels, other than lifestyle changes, most commonly is with medication known as statins. Statins are a class of drugs that lower cholesterol levels in the blood by blocking the enzyme hydroxy-methylglutaryl-coenzyme A reductase, more commonly referred to as HMG-CoA reductase, in the liver.

October 30th, 2007 • mdvaldosta • Conditions and Diseases, High Cholesterol Comments Off


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