When you go to your doctor to have your annual checkup, you can expect to have blood drawn to check your cholesterol levels. This reading is important because high cholesterol is a risk factor for heart disease. While health care providers often only quote your total cholesterol numbers, understanding your relative levels of total, LDL and HDL cholesterol is important for managing your health and nutrition.
Total Cholesterol
Your body naturally manufactures cholesterol in your liver from a combination of fats and proteins, creating lipoproteins. Lipoproteins transport fats, vitamins and other substances through the bloodstream to your cells for energy and repairs. According to University of Iowa's Helmut Schrott, MD, you need cholesterol for cell wall function and the production of hormones. But when cholesterol levels get too high, they can build up on your arterial walls, predisposing you to heart disease. Cholesterol results are expressed as milligrams per deciliter of blood, or mg/dL. Desirable total cholesterol levels are below 200 mg/dL, with 200-239 considered borderline high and over 240 considered high.
LDL Cholesterol
Low-density lipoprotein, or LDL, is often deemed the "bad" cholesterol because, when too much of it circulates in the bloodstream, it can deposit plaque on the walls of arteries, potentially blocking blood flow to the heart and brain. According to Harvard Medical School, LDL cholesterol makes up 60 to 70 percent of total cholesterol, with very low density lipoprotein, or V-LDL, the precursor to LDL, making up 10 to 15 percent of total cholesterol. The Mayo Clinic lists "ideal" levels of LDL at 100 to 129 mg/dL, with 130 to 159 considered borderline high,160 to 189 as high, and above 190 as dangerously high.
HDL Cholesterol
High-density lipoprotein, or HDL, is called "good" cholesterol because it can unload built-up cholesterol from the arteries and carry it to the liver for removal from the body, a process sometimes referred to as the reverse cholesterol pathway. According to Harvard Medical School, HDL cholesterol makes up 20 to 30 percent of total cholesterol. The Mayo Clinic lists HDL levels above 60 m/dL as "best," and levels below 40 for men or 50 for women as "poor."
Total Cholesterol to HDL Ratio
Another important score is your ratio of total-cholesterol-to-HDL. To get this number, divide your total reading cholesterol by your total HDL. The smaller the number, the better off you are. Even if your total cholesterol is a bit high, a high HDL score can keep you at a healthy ratio. For example, if your total cholesterol is 200 and your HDL is 60, both considered "ideal" your ratio is 3.3. But if your total cholesterol is 220 and your HDL is 67, your ratio is also 3.3.
