Cholesterol is a water-insoluble steroid molecule that serves many functions in the human body, from cell membrane structure to the backbones of many hormones. However, too much cholesterol can be detrimental to human health, as it can build up in blood vessels and cause plaques. Because there are three measures of a body's cholesterol level --HDL, LDL and triglycerides--it's important to recognize the significance of these three measures in terms of the risks they may pose to your health.
Good vs Bad Cholesterol
Because cholesterol is insoluble in water, and thus blood, it must be carried through the body on a number of different lipoproteins, or fat-protein complexes. The most important of these are chylomicrons, which transport cholesterol from the intestine to the liver, and high- and low-density lipoproteins--HDL and LDL--that transport cholesterol to the rest of the body. LDL is the so-called "bad cholesterol," but in reality it's the same molecule of cholesterol, just a different lipoprotein carrier. LDL over 100 mg/dL is considered above optimal.
Reading the Charts
A normal breakdown of your cholesterol levels shows HDL, LDL, triglyceride and overall numbers. Optimal levels overall are under less than 200mg of cholesterol/dL of blood. Of this number, only 100 mg/dL should be LDL or bad cholesterol. HDL is trickier, as higher concentrations are considered protective against heart disease, so at least 60 mg/dL is good. But less than 40 mg/dL for men and less than 50 for women may increase risk of heart disease. Triglyceride levels should be below 150 mg/dL.
Risks Associated with High Cholesterol
Non-optimal levels of LDL--which can be broken into above optimal, borderline high, high and very high--come with an increased risk for atherosclerosis and heart problems. These include heart attack, as this kind of lipoprotein-cholesterol complex is apt to form plaques. These levels are defined by blood LDL concentrations of 100 to 129, 130 to 159, 160 to 189 and 190 mg/dL and above. The average for Americans older than 20 is above optimal at 115 mg/dL.
Diagnosis
Cholesterol levels are diagnosed by a blood test. Don't consume anything for 12 hours before the test for best results; eating or drinking may cause the test to reflect your meal rather than your body's normal cholesterol level. Blood test results should show you an overall cholesterol concentration number, as well as a breakdown of LDL, HDL and triglyceride concentrations.
Prevention/Solution
Propensity for high cholesterol and heart disease is heritable, and, according to the Mayo Clinic, recommended levels of LDL are even lower for those with a family history or other high risk of heart disease--below 70 mg/dL instead of 100. A low-cholesterol diet and exercise have been proven to reduce LDL as well as the risks that go with it. Several drugs on the market help manage cholesterol, with Lipitor probably the best known.
