Two types of lipoproteins carry cholesterol in the blood, including low-density lipoprotein, or LDL cholesterol, and high-density lipoprotein, or HDL cholesterol. Doctors refer to HDL cholesterol as "good" cholesterol because it transports cholesterol from blood vessels to the liver for removal from the body. LDL cholesterol, or "bad" cholesterol, deposits harmful plaque in vessel walls. An LDL cholesterol level of 138 would be unhealthily high, while a total cholesterol level of 138 would be quite low.
Total Cholesterol
In the United States and some other countries, doctors measure cholesterol levels in milligrams per deciliter of blood, or mg/dl. Aim for a total cholesterol level below 200 mg/dl. A total cholesterol level between 200 and 239 mg/dl indicates borderline high cholesterol, and a total level above 240 mg/dl indicates high cholesterol.
LDL Cholesterol
High levels of LDL cholesterol increase your risk for coronary heart disease. LDL cholesterol levels below 100 mg/dl represent the ideal for people at risk of heart disease. Factors such as previous heart attacks or strokes, artery blockages in the neck, arms or legs, smoking, high blood pressure, low HDL cholesterol, diabetes and family history of early heart disease can put you in the high-risk group for heart disease. People in this group should aim for an LDL cholesterol level below 70 mg/dl. Some doctors say levels this low would be healthier for everyone. LDL cholesterol levels between 138 and 159 mg/dl are borderline high, and levels above 190 mg/dl are very high.
HDL Cholesterol
Too-low HDL cholesterol levels may increase your risk for heart disease. Men with HDL cholesterol levels below 40 mg/dl and women with levels below 50 mg/dl have greater health risk. Aim for HDL cholesterol levels of 60 mg/dl and above. You can increase your HDL cholesterol levels by making healthy changes to your lifestyle, such as quitting smoking, losing weight, getting more exercise and limiting your intake of saturated fat.
Too-low Cholesterol and Cholesterol Ratio
In rare cases, having too-low levels of LDL cholesterol may put you at higher risk of some health problems, including cancer, depression and anxiety. Sufficient research has not been shown to define these risks more clearly. Having too-low HDL cholesterol makes you more vulnerable to heart disease. A total cholesterol level of 138 with a high ratio of total cholesterol-to-HDL may indicate an unhealthily low level of HDL cholesterol and an unhealthily high level of LDL cholesterol. For example, a person with a total cholesterol level of 138 mg/dl and an HDL cholesterol of only 30 mg/dl would have a total cholesterol-to-HDL ratio of 4.6 to 1, indicating slightly higher than average risk for heart disease for women. This person would also have an LDL cholesterol level above 100 mg/dl, a slightly higher than ideal level. A total cholesterol-to-HDL ratio of 5 to 1 indicates average risk of heart disease for men, and a ratio of 4.4 to 1 indicates average risk for women. A ratio of 3.4 to 1 indicates half the average risk for men, and a ratio of 3.3 to 1 indicates half the average risk for women.
References
- MayoClinic.com; Can Your Total Cholesterol Level be Too Low?; Thomas Behrenbeck; August 2010
- MayoClinic.com; Cholesterol Levels: What Numbers Should You Aim For?; June 2010
- MayoClinic.com; How to Boost Your "Good" Cholesterol; July 2010
- Harvard Medical School Family Health Guide; Making Sense of Cholesterol Tests; February 2005
