wrong with Joes diet? Basically, it contained too much cholesterol and fat,
especially saturated fat. From his youth, Joe had been setting himself up for
coronary heart disease with nearly every forkful of food. A high-fat diet is, in
fact, linked to five of the ten leading causes of death in the United States. At
the top of the list is coronary disease.
connection between diet and heart disease is seen in a study conducted in seven
countries on some 12,000 men aged 40 to 49. The extremes are particularly
revealing. The study showed that Finnish men eating 20 percent of their calories
as saturated fat had elevated blood-cholesterol levels, while Japanese men
eating only 5 percent of their calories as saturated fat had low
blood-cholesterol levels. And the Finnish men had a rate of heart attack six
times greater than the Japanese men!
Coronary heart disease, however, is no longer rare in Japan. In the past several years, as Western-style fast foods have become popular there, the consumption of animal fats has gone up 800 percent. Now, Japanese boys have even higher blood-cholesterol levels than American boys of the same age! Clearly, dietary fat and cholesterol are implicated in life-threatening conditions, particularly heart disease.
The Role of Cholesterol
Cholesterol is a white, waxy substance that is essential to life.
It is found in the cells of all humans and animals. Our liver produces
cholesterol, and it is also found in varying amounts in foods we eat. Blood
carries cholesterol to the cells in molecules called lipoproteins, which are
composed of cholesterol, fats, and proteins. The two types of lipoproteins that
carry most of the blood cholesterol are low-density lipoproteins (LDL) and
high-density lipoproteins (HDL).
rich in cholesterol. As they circulate in the bloodstream, they enter cells
through LDL receptors on cell walls and are broken down for use by the cell.
Most cells in the body have such receptors, and they take up some LDL. But the
liver is designed so that 70 percent of the removal of LDL from the bloodstream
by LDL receptors occurs there.
the other hand, are cholesterol-thirsty molecules. When traveling through the
bloodstream, they soak up surplus cholesterol and transport it to the liver. The
liver breaks down cholesterol and eliminates it from the body. The body is thus
marvelously designed to utilize the cholesterol it needs and to discard the
problem occurs when there is excessive LDL in the blood. This increases the
possibility of a buildup of plaque on artery walls. When plaque buildup occurs,
the arteries become narrow and the amount of oxygen-carrying blood that can pass
through them decreases. This condition is called atherosclerosis. The process
continues slowly and silently, taking decades to manifest discernable symptoms.
One symptom is angina pectoris, or chest pain, like Joe experienced.
coronary artery is completely blocked, often by a blood clot, the part of the
heart that receives blood from that artery dies. The result is a sudden, often
deadly, myocardial infarction better known as a heart attack. Even partial
blockage of a coronary artery can lead to death of heart tissue, which may not
be manifest by pronounced physical discomfort. Blockage of arteries in other
parts of the body can cause strokes, gangrene of the legs, and even loss of
Not surprisingly, LDL
is called bad cholesterol, and HDL good cholesterol. If LDL tests high or HDL
low, the risk of heart disease is high. A simple blood test will often indicate
impending danger long before a person experiences noticeable symptoms, such as
angina. It is important, then, to keep your blood-cholesterol level in check.
Let us now see how your diet can affect this level.
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
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
diet rich in fats and cholesterol always increase blood cholesterol? Not
necessarily. Joe, mentioned in the opening article, decided to take a blood
test. The results revealed that his cholesterol levels were within the desired
limits. His liver was evidently able to keep the cholesterol level regulated.
however, does not mean that Joe 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 thats why eating less cholesterol must be of
concern to all people, irrespective of their blood cholesterol level.
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 societys 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.