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ACSM'S Health & Fitness Journal:
doi: 10.1249/01.FIT.0000244886.24748.4f
Departments: You Asked For It: Question Authority

You Asked For It: Question Authority

Nieman, David C. Dr.PH, FACSM

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David C. Nieman, Dr.PH, FACSM, is a professor and director of the Human Performance Laboratory, Appalachian State University, in Boone, North Carolina, an active researcher, and author of several textbooks on health and fitness. E-mail your questions to niemandc@appstate.edu.

Q: My doctor says my high-density lipoprotein (HDL) cholesterol is too low, and my low-density lipoprotein (LDL) cholesterol is too high. He gave me some medication, but I am more interested in trying to improve my cholesterol numbers by improving my health habits. What do you recommend?

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A: There is much you can do to increase your HDL cholesterol and decrease your LDL cholesterol through lifestyle improvements. In fact, governmental health officials recommend that most American adults with cholesterol problems first change their health habits for 3 to 6 months before resorting to medications (1).Cholesterol is a waxy substance that circulates in the bloodstream. Your body makes its own cholesterol and also absorbs cholesterol from certain kinds of foods, specifically all animal products (i.e., meats, dairy products, and eggs). Cholesterol is transported through the blood by carriers called lipoproteins. Two specific types of cholesterol carriers are called high-density lipoprotein and low-density lipoprotein. Cholesterol carried in the LDL is called "bad" cholesterol because it contributes to the buildup of atherosclerosis or deposits in the blood vessels, increasing heart disease risk.

Try to keep your LDL cholesterol as low as possible. For all age groups, a blood LDL cholesterol less than 100 mg/dL is optimal because heart disease is rare below this level. At the very least, children and adolescents should keep their blood LDL cholesterol less than 100 mg/dL, and adults, less than 130 mg/dL. The Table outlines how LDL cholesterol is classified for adults (1, 2).

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In contrast, HDL cholesterol is called the "good" cholesterol. The HDL carrier acts as a shuttle as it takes up cholesterol from the blood and body cells and transfers it to the liver, where it is used to form bile acids. Bile acids pass from the liver to the intestine to aid in fat digestion. Eventually, some of the bile acids pass out of the body in the stool, providing the body with a major route for excretion of cholesterol.

For this reason, HDLs have been called the "garbage trucks" of the body, collecting cholesterol and dumping it into the liver. Thus, if levels of HDL cholesterol are high (i.e., 60 mg/dL or more), the risk for heart disease is decreased. An HDL cholesterol level of less than 40 mg/dL is considered low or undesirable (1, 2).

How can you ensure a good blood lipoprotein profile-low LDL cholesterol and high HDL cholesterol? Several lifestyle factors have a strong influence. In order of importance, the factors that increase HDL cholesterol are as follows:

* Moderate to vigorous aerobic exercise (e.g., brisk walking), at least 80 to 90 minutes per week. (Note: if your risk for heart disease is high, first check with your doctor before initiating an aerobic exercise program)

* Maintaining a lean body weight and avoiding weight gain

* Smoking cessation

The most important factors for lowering LDL cholesterol are the following:

* Reduction of dietary saturated fat intake to less than 7% to 10% of calories (found mainly in meats, dairy products, and some tropical oils such as palm and coconut oil), with a greater emphasis on most plant oils and fish which are high in unsaturated fats

* Reduction in body weight (if high)

* Reduction in dietary cholesterol intake to less than 200 to 300 mg/d (found in foods of animal origin)

* Increase in carbohydrates to more than 55% of calories and dietary fiber to more than 20 g/d (especially fruits and vegetables, beans, and oat products)

Diets using nonhydrogenated unsaturated fats as the main form of dietary fat (e.g., olive and canola oils), whole grains as the main form of carbohydrates, an abundance of fruits and vegetables, and adequate omega-3 fatty acids from fish will have a strong effect in improving your blood lipids and lipoproteins. This type of diet combined with regular physical activity, avoidance of smoking, and maintenance of a healthy body weight will help you control your blood lipid levels while also reducing your odds of heart disease (3).

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The good news is that these lifestyle changes have strong, relatively quick effects on improving your blood lipid and cholesterol profile. In fact, lifestyle changes often cause meaningful improvements in HDL cholesterol and LDL cholesterol within the first month (4, 5).

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The new "statin" drugs (e.g., lovastatin [Mevacor®], simvastatin [Zocor®], and atorvastatin [Lipitor®]) are easy to use and have a powerful effect in lowering LDL cholesterol and in raising HDL cholesterol (1). They work by blocking an enzyme needed to produce cholesterol in the liver. Typical improvements with these drugs include an 18% to 55% decrease in LDL cholesterol, 5% to 15% increase in HDL cholesterol, and a 7% to 30% decrease in triglycerides (1). But weight loss, exercise, and a healthy diet low in animal fats and high in fruits, vegetables, and whole grains work just about as well while providing many other health benefits.

All drugs have undesirable side effects, and for the statin drugs, they include nausea, diarrhea, constipation, muscle pain and tenderness, and elevated liver enzymes in some individuals. The desirable side effect of an improved lifestyle is feeling better mentally and physically.

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References

1. Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III), 2001. Available at: http://www.nhlbi.nih.gov/.

2. Grundy, S.M., J.I. Cleeman, C.N.B. Merz, et al. Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III Guidelines. Circulation 110:227-239, 2004.

3. Hu, F.B., and W.C. Willett. Optimal diets for prevention of coronary heart disease. The Journal of the American Medical Association 288:2569-2578, 2002.

4. Barnard, R.J. Effects of life-style modification on serum lipids. Archives of Internal Medicine 151:1389-1394, 1991.

5. Nieman, D.C., D.W. Brock, D. Butterworth, et al. Reducing diet and/or exercise training decreases the lipid and lipoprotein risk factors of moderately obese women. Journal of the American College of Nutrition 21:344-350, 2002.

© 2006 American College of Sports Medicine

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