Cholesterol has a bad connotation among most people due to its association with serious and sometimes deadly diseases. However, cholesterol is a very important structural component that is required for numerous metabolic functions. Maintaining healthy cholesterol ranges ensures proper function of major body systems and avoidance of life-threatening conditions.
Functions and Sources
Cholesterol has numerous functions in biochemical metabolism and is the most abundant steroid in the human body. Cholesterol aids in the metabolism of the fat-soluble vitamins A, D, E, and K, composes a significant part of the plasma membrane around cells and is the precursor molecule for the synthesis of other important compounds, such as bile used in digestion, and steroid hormones, such as estrogen and testosterone. The body, specifically the liver, synthesizes all the cholesterol needed to maintain proper body functioning on a daily basis. However, since cholesterol is a component of all animal fat, all animal food products contain varying amounts of cholesterol, including eggs, cheese and poultry.
HDL Cholesterol and Range
HDL, or high-density lipoprotein, is known as "good" cholesterol. The descriptive "high-density" refers to the compound's high amount of protein compared to its low amount of fatty acids known as triglycerides. HDL transports blood cholesterol, both natural and ingested, away from arteries and back to the liver where it can by modified or broken down. According to the American Heart Association, some medical experts believe that HDL removes excess cholesterol from arterial plaque, slowing its buildup. Current U.S. medical guidelines recommend that patients maintain HDL blood levels of at least 50 or mg/dL for women and 40 mg/dL; levels at 60 mg/dL and above indicate very healthy cholesterol levels and metabolism.
LDL Cholesterol and Range
LDL, or low-density lipoprotein, cholesterol contains more triglycerides than protein. This "bad" cholesterol presents little risk in low levels, but consistently high concentrations in the blood lead to cholesterol and plaque buildup in the arteries. Some genetic factors cause higher levels of LDL than HDL in the blood; however, high LDL is most attributed to lack of physical activity, diets high in unsaturated fat, trans fat and cholesterol, cigarette smoking, diabetes and obesity. LDL blood levels should be kept between 100 and 129 mg/dL to ensure low risk of associated diseases. Patients with a high risk of heart disease due to genetics or other risk factors should maintain levels below 70 milligrams per deciliter.
Associated Diseases
Consistently high levels of LDL and triglycerides and low levels of HDL can lead to chest pain and coronary artery disease. If cholesterol and plaques in the arteries leading to the heart and brain continue to buildup unchecked, they could eventually block blood circulation to those organs, resulting in heart attack or stroke.
Treatment
Lowering and maintaining healthy cholesterol levels involves oral medication and lifestyle changes. Oral prescriptions work by blocking cholesterol synthesis in the liver, inhibiting absorption of dietary cholesterol in the digestive system, and increasing bile production in the liver to reduce excess cholesterol. Lifestyle changes include losing weight, increasing physical activity, incorporating more whole grains, soluble fiber, low-fat fish, fruits and vegetable in one's diet and reducing trans and unsaturated fat, dietary cholesterol and alcohol.
References
- "Human Physiology;" Dee Unglaub Silverthorn; 2009
- "Biochemistry;" Reginald H. Garrett, Charles M. Grisham; 2008
- American Heart Association: Good vs. Bad Cholesterol
- MayoClinic.com: High Cholesterol
