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Blood cholesterol values raise fear in the hearts of many. But they don't tell the whole story. Read on to put things into perspective. Diet alone cannot control
cholesterol levelQuestion: What is cholesterol, and do we need it?
Answer: Cholesterol is an essential chemical that serves many functions in the body, including serving as an essential structural component in all cells. The body also needs cholesterol to form the protective layer surrounding nerve fibers. Essential "steroid" hormones such as estrogen and testosterone are made from cholesterol, and it is even used to produce the vitamin D formed when the skin is exposed to sunlight.
Cholesterol is so important that the body makes it. Consequently, cholesterol is not required in the diet, and some people have high blood cholesterol levels even when they don't consume cholesterol.
Q: How does cholesterol cause heart disease?
A: It doesn't. Blood cholesterol, not dietary cholesterol, is correlated or related to an increased risk of heart disease. Some people live long, healthy lives with high blood cholesterol levels and never develop heart disease. Conversely, some people with low cholesterol levels die from heart disease. By itself, cholesterol is only part of the picture. Other factors are essential for heart disease to develop.
Q: How can a person have high blood cholesterol if they don't eat any foods that contain cholesterol, such as eggs and other animal products?
A: The body typically makes about 1,000 milligrams of cholesterol each day to supply its own needs. Eating foods with cholesterol tends to reduce the amount the body makes, resulting in little or no change in blood levels.
American Heart Association recommendations now allow one egg per day in the diet, an amount comparable to the average intake of eggs in Japan.
Q: Why is LDL called "bad" cholesterol and HDL called "good" cholesterol?
A: LDL (low-density lipoprotein) and HDL (high-density lipoprotein) are small particles composed of fats, cholesterol and protein. These forms are needed to transport fat and cholesterol through the watery medium of the blood.
High blood levels of "bad" LDL increase the risk of atherosclerosis due to the accumulation of plaque that contains cholesterol and other substances that cause narrowing of arteries. This, in turn, can cause heart disease or stroke. "Good" HDLs carry cholesterol away from the body's cells and deliver it to the liver to make bile. This tends to reduce the accumulation of plaque.
A "blood cholesterol value" includes all forms of cholesterol in the blood. If total blood cholesterol is high, it is important to determine the ratio of LDLs compared to HDLs.
Q: Are there other factors that cause plaque accumulation in the artery walls?
A: Yes. Cigarette smoking and poorly controlled diabetes are associated with increased plaque accumulation. And genetically, some individuals produce a chemical called homocysteine which increases plaque development.
To prevent plaque buildup, listen to Mom and eat plenty of fruits and vegetables and take your daily vitamin.
Other factors that help lower LDLs and/or increase HDLs: Limit total fat and saturated fat in the diet. Include omega-3 fatty acids and low-to-moderate amounts of alcohol. Exercise daily and, most important, maintain a healthy weight.
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Alan Titchenal, Ph.D., C.N.S., is a sports nutritionist in the
Department of Human Nutrition, Food and Animal Science,
University of Hawaii-Manoa.Joannie Dobbs, Ph.D., C.N.S., is a food and nutrition consultant
and owner of Exploring New Concepts, a nutritional consulting firm.
She is also responsible for the nutritional analyses
indicated by an asterisk in this section.