An estimated 50 percent of U.S. adults have high cholesterol levels that place them at increased risk of heart disease and stroke, according to the American Heart Association. While your body needs cholesterol to make hormones, cell tissues and for nerve protection, in high levels, cholesterol can pose significant health risks, FamilyDoctor.org says. Understanding the function of both types of cholesterol---LDL and HDL---and optimal levels, can help you make lifestyle choices to protect your health.
Function
Cholesterol is a waxy substance found in the bloodstream and cells in the body, the American Heart Association says. Because cholesterol does not dissolve in your blood, it travels to cells in packages of fat and protein known as lipoproteins, the National Heart Lung and Blood Institute's National Cholesterol Education Program notes. Low-density lipoproteins, or LDL, bring cholesterol to tissues in your body, while high-density lipoproteins, or HDL, carry cholesterol away from the bloodstream and tissues to the liver where it is excreted from the body.
Target Levels
Cholesterol levels are measured in milligrams of cholesterol per deciliter. An optimal level of total cholesterol, or LDL and HDL cholesterol combined, is less than 200 mg/dL, according to FamilyDoctor.org. Levels of 240 mg/dL or more are considered to be in the high-risk zone.
An LDL level below 100 mg/dL for people with heart disease or diabetes is optimal, while 100 to 129 mg/dL is optimal for those without these risk factors, FamilyDoctor.org notes. An LDL level that is too high causes cholesterol to accumulate in the artery walls, constricting blood flow and clogging the arteries with plaque, the American Heart Association says. When this plaque ruptures, a blood clot can form, causing a heart attack or stroke.
Conversely, the higher the HDL level, the better. An HDL level of 60 mg/dL or higher reduces your risk of heart disease, while a level less than 40 mg/dL increases your chances of developing heart disease, the National Heart Lung and Blood Institute's National Cholesterol Education Program notes.
Risk Factors
Genes, age, sex and diet are all risk factors for high LDL levels in the blood. According to the National Heart Lung and Blood Institute's National Cholesterol Education Program, high blood cholesterol can be hereditary and increases with age. Women 50 or younger usually have a lower total cholesterol level than men of the same age, the program adds. Diet is also a risk factor. Foods high in saturated fat, trans fat and cholesterol contribute to high LDL levels.
Prevention
Lower your LDL level and increase your HDL level by quitting smoking and avoiding foods high in saturated and trans fats such as fatty meats, butter, cheese and French fries, the University of Maryland Medical Center advises. Instead, choose lean protein such as soy, fish, and skinless chicken as well as whole grains, fatty fish and high-fiber foods. Quitting smoking alone can boost your HDL level by up to 10 percent, according to MayoClinic.com. Similarly, lose weight and exercise for at least 30 minutes each day, the American Heart Association recommends. HDL levels increase by about 5 percent from aerobic exercise and by 1 mg/dL for every 6 lbs. lost, according to MayoClinic.com.
Considerations
Cholesterol levels begin to rise at age 20 and with no symptoms, it is important to monitor your levels, MayoClinic.com says. Have your doctor test your cholesterol levels beginning at 20 years old and then every five years to watch your cholesterol levels.
References
- American Heart Association: What are High Blood Cholesterol and Triglycerides?
- FamilyDoctor: Cholesterol---What Your Level Means
- National Heart Lung and Blood Institute: Your Guide to Lowering Cholesterol with Therapeutic Lifestyle Changes (TLC)
- University of Maryland Medical Center: Cholesterol and Lifestyle
- MayoClinic.com: HDL Cholesterol---How to Boost Your Good Cholesterol
