Cholesterol is wax-like steroid that you need for life itself. Without it, your body could not repair cells, synthesize vitamin D from sunlight shining on your skin or make hormones, such as estrogen and testosterone. However, the adage that there can be too much of a good thing certainly applies to cholesterol. If blood levels of cholesterol become too high, atherosclerosis and cardiovascular disease are the eventual results.
Source of Cholesterol
Your liver can make all the cholesterol your body needs. In addition, any food from animal sources contains cholesterol; food from plant sources is cholesterol-free. Ideally, when you eat dietary cholesterol, your liver reduces production to compensate for the amount you have consumed. However, this process may not always work as it should or you might consume more cholesterol than your body can compensate for, resulting in high levels in the blood.
Lipid Profile
Lipids are composed primarily of cholesterol, triglycerides and a protein called lipoprotein. A lipid profile usually consists of four tests done on a sample of blood. The tests measure total cholesterol, high-density lipoprotein or HDL, low-density lipoprotein or LDL, and triglycerides. The level of very-low-density lipoprotein--or VLDL--is sometimes reported as well.
Total Cholesterol
Total cholesterol is the sum of LDL, HDL and VLDL. A desirable total cholesterol is less than 200 mg/dL. Between 200 and 239 mg/dL is borderline high and over 240 is high. By itself, knowing your total cholesterol number isn't enough. For optimal health, HDL needs to be high, while LDL and VLDL need to be low. Because total cholesterol is the sum of these three readings, there is no way to know which are high and which are low.
VLDL
Your liver packages cholesterol and triglycerides with a protein coating to form VLDL, or very-low-density lipoprotein. As VLDL moves through the blood, an enzyme strips off triglycerides for use by tissues, leaving a higher proportion of cholesterol. LDL--or "bad" cholesterol--is the eventual result. Because VLDL cannot be measured directly, it is estimated as a percentage of your triglyceride level. It should be between 5 and 40 mg/dL.
LDL and HDL
LDL continues to circulate in the blood, delivering cholesterol to tissues. HDL--or "good" cholesterol--gathers unused cholesterol in your blood and other tissues and returns it to your liver for disposal. Any excess LDL may be oxidized, resulting in inflammation and plaque buildup in arteries. If you have had a heart attack or are at high risk for heart disease due to other factors, your LDL should be less than 70 mg/dL. Otherwise, a level of 100 mg/dL or under is considered optimal. LDL levels above 190 mg/dL are considered very high and likely require medication. HDL levels should be at least above 40 mg/dL, but above 60 mg/dL is better. HDL also has antioxidant properties which help prevent the oxidation of LDL.
References
- Northern Arizona University: Plasma Lipoprotein Transport
- Lab Tests Online: Lipid Profile
- Harvard Health Publications; Which cholesterol test should you get?; November 2004
- MayoClinic.com: VLDL cholesterol: Is it harmful?; T. Behrenbeck; April 2010
- University of Maryland Medical Center: Cholesterol; H. Simon MD; 2009
