Cholesterol Explained

In passing you might have heard someone say that he has high cholesterol. Or maybe you have been told by your doctor that your cholesterol is too high and she has suggested that you start on medication. Well, just what is cholesterol and what are the consequences of continued high blood levels of it?

Cholesterol is a waxy-fatty substance (a steroid) that is used to perform important functions by the body's cells. It can be made by most of the body's cells, but the main supply is produced in the liver. Every day the liver manufactures enough cholesterol for the body's needs. So any cholesterol we ingest (called dietary cholesterol) is not needed.

Cholesterol's importance cannot be overstated because we need it to survive. The rub comes in when we eat too much of the wrong kind of food. Only animals produce cholesterol. So if we eat a lot of animal products we are eating cholesterol. Although it would seem that if we stop eating foods coming from animal sources we could end our cholesterol problems - in fact that is not the case. The main cause for rises in blood cholesterol levels are saturated fats - they are the culprits.

Saturated fats can come from animal or vegetable sources. Our liver converts saturated fats to cholesterol and since we already have enough for our needs, this dietary cholesterol is extra and is free to do damage to our arteries and accelerate heart disease. In general, the more saturated fats we eat the higher our cholesterol levels become.

Consequences of High Cholesterol

High levels of cholesterol encourages the accumulation of cholesterol in the artery walls. As the walls fill up the flow of blood is restricted. This may cause pain from the chest area after a physical exertion, but in many cases it goes unnoticed. A hardened plaque build up occurs further blocking blood flow. If part of the plaque becomes unstable and tears off it may cause a clogged artery, choking off the heart muscle that is fed through it. A heart attack occurs which may be fatal.

The preceding was a brief explanation of the atherosclerotic process. The scary part of it all is that most of the stages may go unnoticed and then a person has a heart attack. That's where the term silent killer came from. This is the reason that people who are told that they have high cholesterol must heed what their doctor is telling them with a sense of urgency and seriously take the appropriate measures to bring it down to healthy levels.

LDL Cholesterol

Low density Lipoprotein cholesterol (LDL cholesterol) is produced in the liver. As explained above, cholesterol is a waxy-fatty substance which looks similar to white-yellow candle wax. The liver makes it and wraps it in a protein sheath which allows for easy transport in the bloodstream. In its natural form it would clog the blood since blood is a watery liquid and the fatty mixture would not mix well. Lipo means fat and protein refers to the sheath wrapped around it; hence, the word - lipoprotein. These neat packages travel in the blood to the cells that need them. LDLs are like little dump trucks carrying cholesterol to the cells.

HDL Cholesterol

High density lipoprotein (HDL) is used to scoop up extra cholesterol (LDLs) in the bloodstream and from the cell walls and return it to the liver for disposal.

When a person has high cholesterol it's usually because he/she has too many LDLs for the number of HDLs. The ratio of the two is out of balance. There are too many LDLs in the bloodstream and consequently they are available to do damage to the cardiovascular system. 

Triglycerides

Triglycerides are the most common kind of fat in the body. An example of a triglyceride is the fat on a beef steak. These fats travel in the blood mainly on their way to storage. Low blood levels are desired.

Cholesterol Levels

Recommended Levels of LDL and HDL in the Blood The National Institutes of Health recommends the following levels:

LDL Blood Cholesterol Levels

Less than 100 mg/dL is optimal or ideal

100-129 mg/dL is near optimal/above optimal

130-159 mg/dL is borderline high

160-189 mg/dL is high

190 mg/dL and above is very high

HDL Blood Cholesterol levels:

Less than 40 mg/dL is a major heart disease risk factor

60 mg/dL and above gives some protection against heart disease

Triglycerides

Less than 150 mg/dL is desirable

150-199 mg/dL is borderline high

200-499 mg/dL is high

500 mg/dl and above should be lowered by medication to prevent further complications.

Total Cholesterol

When your doctor looks at the results of a lab test of your blood (Lipid Profile), she/he will see a value for your total cholesterol. This is computed from your LDL, HDL, and Triglycerides. A common way of computing total cholesterol is through the Friedewald formula which is:

Total Cholesterol = LDL Chol. + HDL Chol. + (Triglycerides/5)

The National Institutes of Health classifies total cholesterol levels of less than 200 mg/dL as desirable. Values of 200-239 mg/dL are borderline high and 240 mg/dL and above are considered high.

More Info

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