Cholesterol gets a bum rap, and for good reason. High levels of cholesterol lead to cardiovascular disease, stroke and obesity and also has been linked to diabetes and cancer. What you may not know is that your body needs some cholesterol to function properly.
The Good
Cholesterol is a dietary fat and serves many functions in your body. The body's cell membranes are lined with phospholipids, a form of fat that protects cells, which could not function without it. Fat is needed to dissolve, store and transport many vitamins such as A, D, E and K. In addition, your body cannot produce hormones without cholesterol, and it also serves to preserve body temperature. Most of your body's energy comes from carbohydrates, but a large portion of your energy comes from fat--especially for endurance athletes. Bottom line: You need fat.
The Bad
Too much fat, however, is a problem. Because cholesterol is a fat, it cannot be dissolved in your body and is carried through the bloodstream to the liver, where it is processed and excreted. Special proteins, called lipoproteins, carry cholesterol through the bloodstream. There are two types of cholesterol: low-density lipoprotein (LDL, the bad cholesterol) and high-density lipoprotein (HDL, the good cholesterol).
The Ugly
LDL (think "L" for "lousy") tends to be in the highest concentration in the bloodstream and can cause plaque on artery walls, leading to artherosclerosis. These plaques can cause a heart attack or stroke. The American Heart Association (AHA) recommends LDL levels under 160 mg/dl for healthy individuals, and for those who already have heart disease, under 100 mg/dl. Increases in LDL are typically due to higher levels of saturated fat in the diet--those that are solid at room temperature. Animal protein contains high levels of saturated fat, and careful attention needs to be paid in choosing low-fat varieties. This includes meat, fish, poultry and dairy. People with a family history of high cholesterol levels may have a predisposition toward high cholesterol themselves.
It's Not All Bad
HDL is considered healthy by doctors because higher levels of this variety of cholesterol tend to protect the body against the build-up of plaques. The AHA recommends levels of HDL above 40 mg/dl for men and 50 mg/dl for women and recommends that everyone keep total daily consumption of dietary cholesterol to less than 300 mg per day.
What About Exercise?
Physical activity can also help improve cholesterol levels. The American Council on Exercise recommends that anyone with elevated levels of cholesterol see his doctor prior to starting an exercise program. Tests may be needed before exercising vigorously. The council also recommends moderate exercise, which means on a scale of one to ten, with one being no exercise and ten being vigorous exercise, set a goal of about four to seven. The council, however, warns that the most significant results in cholesterol levels come from dietary modification, not exercise. However, exercise reduces fat mass, and that is healthy, so if your doctor says it's OK, get moving.
References
- American Heart Association: Cholesterol
- American Council on Exercise: Get Fit--Managing Cholesterol with Exercise
- "Physiology of Sport and Exercise"; Jack H. Wilmore; 2008
