Cholesterol is a sterol (Figure 5-2). It is not a true fat but a fatlike substancethat exists in animal foods and body cells. It does not exist in plant foods. Cholesterol is essential for the synthesis of bile, sex hormones, cortisone, and vitamin D and is needed by every cell in the body. The body manufactures 800 to 1,000 mg of cholesterol a day in the liver.
Cholesterol is a common constituent (part) of one’s daily diet because it is found so abundantly in egg yolk, fatty meats, shellfish, butter, cream, cheese, whole milk, and organ meats (liver, kidneys, brains, sweetbreads) (Table 5-3).
Cholesterol is thought to be a contributing factor in heart disease be-cause high serum cholesterol, also called hypercholesterolemia, is common in clients with atherosclerosis.
Atherosclerosis is a cardiovascular disease in which plaque (fatty deposits containing cholesterol and other substances) forms on the inside of artery walls, reducing the space for blood flow. When the blood cannot flow through an artery near the heart, a heart attack occurs. When this is the case near the brain, a stroke occurs.
It is considered advisable that blood cholesterol levels not exceed 200 mg/dl (200 milligrams of cholesterol per 1 deciliter of blood). A reduction in the amount of total fat, saturated fats, and cholesterol and an increase in the amounts of monounsaturated fats in the diet, weight loss, and exercise all help to lower serum cholesterol levels. Soluble dietary fiber also is considered help-ful in lowering blood cholesterol because the cholesterol binds to the fiber and is eliminated via the feces, thus preventing it from being absorbed in the small intestine. In some cases, medication may be prescribed if diet, weight loss, and exercise do not sufficiently lower serum cholesterol.
Because the development of plaque is cumulative, the preferred means of avoiding or at least limiting its development is to limit cholesterol and fat intake throughout life. If children are not fed high-cholesterol foods on a regular basis, their chances of overconsuming them as adults are reduced. Thus, their risk of heart attack and stroke is also reduced.