Cholesterol is a substance circulating in your bloodstream that your body uses for purposes that include hormone and cell tissue production, as well as the protection of your nerves. When present in excessive amounts, a form of the substance called LDL or "bad" cholesterol poses a number of significant health risks. HDL, or "good" cholesterol, is a form of cholesterol that reduces the LDL content in your bloodstream.
Lipoprotein and HDL
Your body transports the cholesterol in your body inside particles called lipoproteins, according to the University of Washington. Additional common components of lipoproteins include protein and substances called phospholipids. When a lipoprotein particle contains relatively high amounts of lipids and low amounts of protein, it is called low-density lipoprotein, or LDL. When a lipoprotein particle contains relatively low amounts of lipids and relatively high amounts of protein, it is called high-density lipoprotein, or HDL. Additional types of lipoprotein include very low-density lipoprotein, or VLDL, and particles called chylomicrons.
LDL Effects
Your body produces LDL as a means of transporting cholesterol from your liver to cells throughout your body. Once it reaches your cells, the cholesterol in LDL is incorporated into cellular membranes or used to create steroid hormones. Your body naturally produces enough cholesterol for its needs, according to the American Academy of Family Physicians. If you eat high-cholesterol foods such as meat and dairy products, the extra cholesterol in your body can contribute to the buildup of an artery-blocking substance called plaque. In turn, plaque buildup can trigger hardening or narrowing of your arteries and subsequent conditions such as heart attack and stroke.
HDL Effects
Your body creates the structural underpinnings of HDL particles inside your liver and small intestine. Once they enter your bloodstream, these structures gather excess or unneeded cholesterol molecules and complete their transformation into full-fledged HDL. These complete HDL particles are then transported to your liver, which breaks the particles apart and eliminates their cholesterol content in a digestive secretion called bile. Your liver can also pull some LDL directly from your bloodstream.
HDL Levels
Roughly 25 to 33 percent of your body's circulating cholesterol is carried by HDL particles, according to the American Heart Association. You need to maintain your HDL levels to lower your risks for the development of heart disease, the National Heart Lung and Blood Institute reports. Minimally, you should have 40 to 59 milligrams of HDL per deciliter of blood. If your HDL falls below 40 mg/dL, you have a major risk for the development of heart disease. If your HDL level is 60 mg/dL or higher, your body typically has significant additional protection from heart disease development.
Considerations
According to MayoClinic.com, methods of improving your HDL levels include avoiding or quitting smoking, drinking alcohol only in moderation and avoiding foods that contain a man-made substance called trans fat. You can also increase the effectiveness of your available HDL supply by lowering your levels of LDL cholesterol and another substance called triglyceride. Consult your doctor for more detailed information on managing your cholesterol levels.
References
- FamilyDoctor.org: Cholesterol -- What Your Level Means
- University of Washington: Cholesterol, Lipoproteins and the Liver
- American Heart Association: Good vs. Bad Cholesterol
- National Heart Lung and Blood Institute: How Is High Blood Cholesterol Diagnosed?
- MayoClinic.com: High Cholesterol -- Lifestyle and Home Remedies
