Cholesterol Is?

Dear Eating Right: My husband recently suffered a heart attack. Now his doctor says he should watch his cholesterol. What is the difference between dietary cholesterol and blood cholesterol?

--GLORIA

Dear Gloria: You are not the only one who is confused about cholesterol. In a recent Gallup Poll survey commissioned by the International Food Information Council and the American Dietetic Assn., at least 35% of the people queried said they were unsure of the difference between dietary and blood cholesterol. At least 15% thought they were the same thing.

Cholesterol is a wax-like substance found in body tissues. It is important for proper cell functioning and is found only in animal foods.

Dietary cholesterol is the amount you eat. Therefore, advice to reduce your dietary cholesterol level means you should eat fewer cholesterol-containing foods such as egg yolks, organ meats and certain shellfish.

Blood cholesterol is the amount floating around in the bloodstream for use by cells.

If you are wondering how all of this affects your health, a brief physiology lesson may help. The body is capable of making all the cholesterol it needs to function properly. When you eat cholesterol-rich foods, the cells absorb what they need from the bloodstream and make less of their own.

Cholesterol is carried throughout the body by low-density lipoproteins and high-density lipoproteins. The amounts of both in your body are determined primarily by family history.

LDL is called “bad” cholesterol because it carries cholesterol to the cells. It also has a greater tendency to get stuck in the linings of blood vessels. And, it is influenced somewhat by diet.

HDL, on the other hand, is called “good” cholesterol because it moves cholesterol away from cells to the liver and out of the body. Unfortunately, experts say you cannot change your HDL level with diet; it can only be increased with exercise.

Without sufficient HDL to keep the LDL flowing smoothly, excess cholesterol builds up in the bloodstream and clogs the arteries to the heart. This is what often leads to a heart attack.

(Saturated fat also contributes to the blood cholesterol level. When you eat foods that are high in saturated fat the body converts it into cholesterol. Heredity, smoking, obesity and lack of exercise also contribute to development of heart disease.)

For good heart health, experts explain that a blood cholesterol level of 200 milligrams/deciliter or below is “desirable.” As the level rises above 200, the risk of heart disease increases. “Borderline-high cholesterol” is 200 to 239 milligrams/deciliter and “high blood cholesterol” is 240.

To reduce the risk, keep intake of dietary cholesterol to around 300 milligrams each day. Saturated fat should be limited to 10% of the total daily calories, and total fat should make up just 30% of a diet.

Only questions of general interest will be printed. Eating Right cannot respond to inquiries regarding therapy for a specific ailment, nor is this column designed to replace medical advice. Send diet and health questions to Eating Right, Food Section, The Times, Times Mirror Square, Los Angeles 90053.