Blood Cholesterol and Diet
Cholesterol is a natural part of foods derived from animals. Meat, eggs, fish, poultry, and dairy products all contain cholesterol. Foods from plants, on the other hand, are free of cholesterol.
The body produces all the cholesterol it needs, so cholesterol consumed in food is extra. Most of our dietary cholesterol ends up in the liver. Ordinarily, as dietary cholesterol enters the liver, the liver processes it and decreases its own production of cholesterol. This keeps the total amount of cholesterol in the blood regulated.
What happens, though, if the diet is so abundant in cholesterol that it cannot be quickly processed by the liver? The likelihood of cholesterol directly entering the cells of the artery wall is increased. When it does, the process of atherosclerosis occurs. The situation is especially dangerous when the body continues to make the same amount of cholesterol regardless of the amount of dietary cholesterol consumed. In the United States, 1 in 5 persons has this problem.
Cutting down on your intake of dietary cholesterol, then, is a course of wisdom. But another component of our diet has an even greater effect on the level of blood cholesterol—saturated fats.
Fats and Cholesterol
Fats fall into two categories: saturated and unsaturated. Unsaturated fats can be either monounsaturated or polyunsaturated. Unsaturated fats are better for you than their saturated counterparts, since consuming saturated fats raises the level of cholesterol in the blood. Saturated fats do this in two ways: They help create more cholesterol in the liver, and they suppress LDL receptors on liver cells, reducing the speed of removal of LDL from the blood.
Saturated fats are primarily found in foods of animal origin, such as butter, egg yolks, lard, milk, ice cream, meat, and poultry. They are also prevalent in chocolate, coconut and its oils, vegetable shortening, and palm oil. Saturated fats are solid at room temperature.
Unsaturated fats, on the other hand, are liquid at room temperature. Foods that contain monounsaturated fats and polyunsaturated fats may help to decrease your blood-cholesterol level if substituted for foods containing saturated fats. While polyunsaturated fats, common in corn oil and sunflower-seed oil, reduce both good and bad cholesterol, monounsaturated fats, plentiful in olive oil and canola oil, reduce only the bad cholesterol without affecting the good cholesterol.
Fats, of course, are a necessary part of our diet. Without them, for instance, there would be no absorption of vitamins A, D, E, and K. The fat requirements of the body, however, are very small. They are easily met through the consumption of vegetables, beans, grains, and fruits. So minimizing the intake of saturated fats does not deprive the body of needed nutrients.
Why Reduce Fats and Cholesterol
Will a diet rich in fats and cholesterol always increase blood cholesterol? Not necessarily. Thomas, mentioned in the opening article, decided to take a blood test after his interview with Awake! The results revealed that his cholesterol levels were within the desired limits. His liver was evidently able to keep the cholesterol level regulated.
This, however, does not mean that Thomas is risk free. Recent studies indicate that dietary cholesterol may affect the risk of coronary heart disease independently of its effect on blood cholesterol. “Cholesterol-rich foods promote heart disease even in people with low blood cholesterol,” says Dr. Jeremiah Stamler, of Northwestern University. “And that’s why eating less cholesterol must be of concern to all people, irrespective of their blood cholesterol level.”
There is also the matter of fat in the diet. Too much fat in the blood, be it from saturated or unsaturated fat in the food, causes red blood cells to clump together. Such thickened blood does not pass through the narrow capillaries, causing the tissues to be deprived of needed nutrients. Clumped cells moving along the arteries also disrupt the oxygen distribution to artery walls, causing surface damage, where plaque can easily begin to form. But there is another danger in consuming excessive amounts of fat.
Cancer and Diet
“All fats—saturated and unsaturated—are involved in the growth of certain kinds of cancer cells,” says Dr. John A. McDougall. One survey of the international incidence of colorectal cancer and breast cancer showed alarming differences between Western nations, where diets are high in fat, and developing nations. In the United States, for example, colorectal cancer is the second most common cancer for men and women combined, while breast cancer is the most common for women.
According to the American Cancer Society, groups of people who relocate to a country with high incidences of cancer eventually develop the cancer rate of that land, depending on the length of time it takes for them to switch to the new life-style and diet. “Japanese immigrants to Hawaii,” notes the cancer society’s cookbook, “are developing a Western cancer pattern: high for colon and breast cancer, low for stomach cancer—the reverse of the Japanese pattern.” Evidently, cancer is linked to diet.
If your diet is high in total fat, saturated fat, cholesterol, and calories, you need to make some changes. A good diet can lead to good health and can even reverse many ill effects of a bad diet. In view of such options as painful bypass surgery, which often costs $40,000 or more, this is surely desirable.
By sensibly choosing what you eat, you can lose weight, improve how you feel, and help yourself avoid or reverse some diseases. Hints along this line are discussed in the next article.
Cholesterol is measured in milligrams per deciliter. A desirable level of total cholesterol—the sum of LDL, HDL, and cholesterol in other lipoproteins in the blood—is less than 200 milligrams per deciliter. An HDL level of 45 milligrams per deciliter or higher is considered good.
The 1995 Dietary Guidelines for Americans recommends a total fat intake of no more than 30 percent of daily calories and recommends reducing saturated fat to less than 10 percent of calories. A 1-percent decrease in caloric intake of saturated fats ordinarily leads to a drop of 3 milligrams per deciliter in the blood-cholesterol level.