People are advised by their doctors to limit their cholesterol and saturated fat intake in order to keep their cholesterol levels in the normal range, and to try to increase their levels of good cholesterol while decreasing bad cholesterol levels. The American Heart Association recommends that people eat a heart healthy diet, keep their weight under control, avoid cigarette smoke, and limit alcohol in order to keep their cholesterol and triglyceride levels at a healthy level and limit their risk of heart disease.
Definitions
Total blood, or serum, cholesterol is made up of the combination of high density lipoprotein, or HDL, cholesterol, low density lipoprotein, or LDL, cholesterol, and very low density lipoprotein, or VLDL, cholesterol. HDL cholesterol is what people sometimes call good cholesterol, and LDL cholesterol is what people call bad cholesterol.
Significance
HDL cholesterol has a protective effect on the heart, according to a study in the Journal of the American Medical Association, while LDL cholesterol has been found to increase the risk of coronary heart disease. The ratio between these 'good' and 'bad' cholesterol levels is used by doctors to predict the risk of a person getting heart disease, as is the ratio of total cholesterol to LDL cholesterol.
Theories/Speculation
Although the ratio of LDL to HDL cholesterol is a relatively good predictor of coronary heart disease according to a study in the Journal of the American College of Nutrition, there is still some controversy over the best measurements to use for these predictions. The Quebec Cardiovascular Study results show that in some cases the total cholesterol to HDL cholesterol ratio can be a better predictor of coronary heart disease. This is because in those with elevated triglyceride levels the VLDL levels are higher, and this is not taken into account if the LDL to HDL ratio is used.
Considerations
The American Heart Association says that less than 200 mg/dL is desirable for total cholesterol. HDL levels higher than 60 mg/dL give some protection from heart disease, while those lower than 40 mg/dL put you at increased risk for heart disease. LDL levels are optimal if they are less than 100 mg/dL, and triglyceride levels should be less than 150 mg/dL to be in the normal range.
Expert Insight
Because there are a number of factors that affect your risk for coronary heart disease, it is important that your good and bad cholesterol levels are not the only things considered when determining how likely you are to suffer from this condition, according to the American Heart Association. Doctors should also take into account your family history, your age, any history of smoking and whether or not you have high blood pressure, as these are also risk factors.
References
- American Heart Association: What Your Cholesterol Levels Mean
- Journal of the American College of Nutrition: The LDL to HDL Cholesterol Ratio as a Valuable Tool to Evaluate Coronary Heart Disease Risk
- Archives of Internal Medicine: Total Cholesterol/HDL Cholesterol Ratio vs LDL Cholesterol/HDL Cholesterol Ratio as Indices of Ischemic Heart Disease Risk in Men
- The Journal of the American Medical Association: Incidence of Coronary Heart Disease...
