Cholesterol is not a bad thing in itself. It is, in fact, essential for proper cell function, being a key component of cell membranes. Cholesterol is carried in the blood but cannot be dissolved in it, which means that it must use "vehicles" called lipoproteins for moving about the body. In figuring cholesterol rates, lipoproteins and the cholesterol they contain are essentially interchangeable.
The liver is the engine that churns out the body's cholesterol, producing it in the form of bile. As with many things in the body, however, too much of this good thing can be detrimental. Processing a modern fat-rich diet can create a higher than normal level of cholesterol. Since blood cannot dissolve or wash the cholesterol away, the excess begins accumulating on artery walls and restricting blood flow. This is especially dangerous inside the heart.
Based on medical research, it turns out that the lipoprotein has a split personality -- or, if you will, an evil twin. The High-Density Lipoproteins (HDL) carry "good cholesterol," which performs its function efficiently and is disposed of regularly with the help of the liver. The higher the HDL level, with 34 milligrams of cholesterol per deciliter of blood as a generally accepted baseline, the better. Low Density Lipoproteins, by contrast, are married to a type of cholesterol that tends to accumulate, which means that the lower the level, with 160 being the highest healthy range, the better.
The cholesterol ratio was developed as a means of quantifying the overall status of that substance in the body. One commonly employed cholesterol ratio divides the rate of HDL into the figure for LDL. Another divides the overall cholesterol rating, arrived at through adding the HDL and LDL levels together, by the amount of HDL.
With the aid of the cholesterol ratio, the total cholesterol rating can be interpreted and broken down. For example, a seemingly high total rating with a high level of HDL could actually be encouraging. Conversely, a low HDL score or high LDL numbers hiding within the total are always a red flag.
With the LDL to HDL comparison, a cholesterol ratio of 2.3-4.9 would be normal, below 2.3 very positive, and above 7.2 a definite danger sign. In terms of the ratio of HDL to the total cholesterol ranking, the "average" range is between 3.9-4.7, with 6.0 being dangerously elevated. Some cardiologists are also beginning to experiment with yet a third cholesterol ratio, one that divides the overall rating by the amount of bad cholesterol.