DESTINED FOR DIABETES
Are You at Risk?
With so many people getting diabetes nowadays, will you be one of them? Does it matter whether you are rich or poor, thin or fat, old or young? We have already said that you can’t “catch” diabetes from someone who has it. But how, then, does a person get diabetes? Does it come from eating too much sugar, as I feared when I was a child? And who is likely to get it?
When I was in nurses’ training almost 30 years ago, the lecturers taught that the typical diabetic was “fair, fat, and forty”—the “fairer sex” (female), overweight, and at least 40 years of age. Is that really an accurate description of who is at risk of getting diabetes? What does cause it?
To be quite honest, no one is quite certain yet of the exact causes of diabetes, though scientists do have some pretty good ideas. To complicate matters, the causes are not the same for type I and type II diabetes—except that both seem to have a strong genetic link.
Remember soccer player Roger Lee? He has type I—insulin dependent—diabetes. Well, Grandma Lee also has diabetes. And so does Roger’s brother, Steven.
When Steven was just a teenager, he used to wonder if he would also get diabetes. Maybe I should say that he wondered when he was going to get it. He felt sure that with both his grandmother and his brother already having diabetes, it was probably just a matter of time until he would have it too. He had to wait longer than most type I diabetics, however. He was 23 before he noticed the first signs.
My friend Nancy chose not to believe that diabetes was hereditary. Her father was diabetic. Her mother had diabetes. So did her brother. But, Nancy thought, they all ate too many sweets. They were overweight. Their lifestyle was bad. Surely they had brought the trouble on themselves. She was certain that she would never have diabetes.
Then, at age 50, Nancy suddenly became suspicious. She had read enough to know the signs and symptoms—and to know that there probably was a genetic factor involved after all. When she went to a large university hospital, doctors confirmed her fears. Nancy had type II diabetes, just like her father and mother and brother. She hadn’t “caught” it from the rest of the family—it was in their genes. Will her son and her granddaughter also become diabetics? Only time will answer that question.
Though both type I and type II diabetes appear to have a genetic connection, the genetic factors in type I seem to be very different from those which cause type II. Also, the inheritance of type I is not as predictable as for type II.
We need to look at the two types of diabetes separately to see what doctors suspect are the causes of each.
There are at least two particular genes that give a person the tendency toward developing type I diabetes. They belong to the so-called HLA system, which controls the body’s defenses against infections. (The technical names doctors use for these genes are HLA DR3 and HLA DR 4 for Caucasians; in parts of Asia these plus two additional genes, HLA AW33 and HLA BW 58, appear to be involved.)
Medical researchers—doctors turned detectives—have been trying to find out exactly what causes type I diabetes. Although they still do not fully understand what is happening in the body to cause it, they have made tremendous progress in recent years. They suggest two possible reasons why an already genetically susceptible person may become diabetic.
Diabetes as an Autoimmune Disease
Many scientists now believe that type I diabetes is the result of the body’s immune system attacking its own insulin-producing beta cells in the pancreas. This begins way back during infancy.
When a baby is born, its immune system has not yet developed an “understanding” of what if should or should not attack. The cells in the immune system more at less know what belongs to the body and what is foreign. But they do not yet recognize the various diseases. There is no need for a baby to be born with an immunity to every kind of disease. For example, it is very unlikely that a baby born in Thailand or in the Philippines would ever need to use an immunity to diseases such as Yellow Fever of African sleeping sickness.
As the baby grows, he is gradually exposed to germs of various kinds. With some, such as measles or chickenpox, the young child may become sick with the disease once, but later he will be immune to the particular disease.
For other kinds of germs, such as smallpox, diphtheria, tetanus, polio, etc., the baby gets an immunization when he is still very small. The doctor or nurse injects a small amount of treated germs for the particular disease. Those germs do not actually cause the disease, but the immune cells recognize them as a foreign kind of protein and go on the attack. Later, the child will have an immunity to those diseases for which he received the immunizations.
Whether the child develops an immunity through having the disease or through having the injections, the body’s defense system is actually functioning in the same way.
In the body, the white blood cells carry out the work of protection. Among this army of white blood cells are the special T cells, which are the attack force against foreign proteins such as germs. If a foreign protein enters the body, these T cells launch an immediate advance on the “enemy”.
Another vital unit in the white blood cell army consists of the B cells. These B cells produce antibodies against specific types of invaders, such as measles or polio or smallpox. These antibodies are what give the body its future immunity against a particular kind of disease.
Suppose that Baby Lina had her BCG immunization against tuberculosis when she was only three days old. When she is two years old, Lina and her mother are riding on a bus. The old woman sitting next to them coughs several times. No one knows that she has tuberculosis. But as Lina sits on her mother’s lap, she breathes in some of the tuberculosis germs that the old woman has coughed out.
Fortunately, Lina’s white blood cells have met tuberculosis before—when she had her BCG immunization. Way back then, her B cells produced antibodies against the proteins of the tuberculosis germs. Now, as this same enemy invades again, there is a whole arsenal of weapons ready and waiting just for tuberculosis.
The white cells waste no time sitting around analyzing whether this is really tuberculosis or possibly some other kind of foreign protein that is just similar to tuberculosis. When they see something that looks like it might be tuberculosis, the defenders strike. Apparently the body’s immune system, in its efforts to defend quickly, may sometimes attack look-alikes.
And this is what researchers suspect may be causing type I diabetes in at least some children who already have that genetic tendency toward diabetes. Only in this case, cow’s milk may be the enemy.
Cow’s milk contains several different proteins. An adult’s digestive system is prepared to handle these proteins. However, a baby does not have all the necessary digestive enzymes to break down these proteins into amino acids. It appears that one of these cow’s milk proteins may be somewhat of a look-alike with the beta cells in the pancreas. Therefore, if the small baby is given cow’s milk to drink, his body may develop an immunity against that particular protein. Later, the antibodies against the cow’s milk protein may begin to attack and destroy the insulin-producing beta cells instead. This destruction process may go on for weeks, months, or even years before the person actually shows the signs and symptoms of diabetes.
Obviously, every baby who drinks cow’s milk is not doomed to get diabetes. Yet scientists have already collected enough evidence that they are now more suspicious of milk than ever before.
Mother’s milk has always been the best food for babies. Now, it seems that there are even more reason s for breastfeeding. A nutrition expert predicted years ago that the time would come when it would no longer be safe to drink milk. It appears, at least for babies, this may now be true. Because of the possible link with diabetes and for other reasons as well, the American Academy of Pediatrics has recommended that mothers avoid giving whole cow’s milk to babies under twelve months old.
Diabetes From Virus Infections
Some diabetes specialists believe that diabetes may actually have several causes—not just one—and that cow’s milk is likely only one of those causes. Another suspected cause is a variety of viruses.
There is not a diabetes virus, like we know the flu (influenza) viruses or the chickenpox or measles viruses. Diabetes cannot be “caught” from someone else. But in some people who are genetically susceptible to diabetes, a virus such as that which causes some of the common illnesses may directly attack the beta cells of the pancreas. Or it may possibly trigger an attack by other forces such as the body’s own immune system.
Some studies of people with recently diagnosed type I diabetes show that in many cases the person had recently had a viral infection such as flu, a bad cold, chickenpox, et cetera. Recently diagnosed diabetics also have high levels of antibodies to a particular type of virus by the name of Coxsackie.
Interestingly, many type I diabetics seem also to have other diseases of the endocrine glands such as the thyroid or the adrenal glands. The relationship is not yet clear, however.
With type II diabetes, there is a very strong family tendency toward the disease. If you have one family member with diabetes, your chances of getting it are twice as high as for an average person with no diabetic relatives. If you have two relatives with diabetes, you have four times the normal likelihood of becoming a diabetic yourself.
Recently scientists have discovered a defective gene which may be the cause of 10-20 percent of all cases of type II diabetes. This gene is the one which determines how well the body will produce the digestive enzyme called glucokinase, which appears to play a major role in stimulating the beta cells to release insulin.
Research indicates that with this genetic defect, the body may produce enough insulin to keep the body functioning early in life. Later on, however, environmental factors or severe bodily stresses such as pregnancy or illness may leave the body unable to cope with all of the glucose it receives. And diabetes is the result.
Looking back to the old “fair, fat, and forty” stereotype of a diabetic, there is plenty of evidence that at least the “fat” aspect is a definite risk factor in developing diabetes.
When you eat more calories than your body actually needs, those extra calories are stored in the body as fat—regardless of whether the calories came from carbohydrates, proteins or fats.
Remember that insulin works to move not only glucose but also fats into storage. When fat cells are full, however, they lose some of their ability to respond to insulin, so the pancreas produces more and more insulin in its efforts to get the “doors” of the cells to open. Thus the pancreas has to work overtime to cope with the excess calories you eat. Also, the pancreas may eventually suffer from fatigue and lose some of its ability to produce insulin.
If a person already has diabetes somewhere in his family, he must guard extra carefully against becoming overweight. Simply stated, being overweight is inviting diabetes to begin. Insulin cannot work properly when the body has an excess amount of fat.
Lack of Exercise
For a person to have really good health, two of the most important factors are proper food and regular exercise. Getting regular exercise is one of the best ways of helping to prevent the lifestyle diseases such as diabetes, heart attack and stroke.
According to a recent research report in Lancet, the British medical journal, women can dramatically reduce their risk of getting diabetes by getting regular, vigorous exercise. Such exercise can lower the risk of diabetes even in women who are overweight and in women who have diabetic family members.
Yet how many women actually do take the time to exercise regularly? Among housewives, who should have more time, one Asian study showed that only five to 10 percent get exercise even once a week.
This reduced risk of diabetes through exercise is not just limited to women. Men may also share in the benefit, and it is never too late to benefit from exercise!
The Journal of the American Medical Association reported encouraging findings from a study of more than 21,000 physicians. Results showed that exercising five times a week resulted in a 42 percent reduction in the expected number of cases of type II diabetes. Exercising even once a week lowered these 40- to 84-year-old physicians’ chances of getting diabetes.
Children enjoy playing actively, so it seems that it should be no problem for them to get enough exercise. However, with increased affluence, more and more families are able to afford televisions, computers, and video games which keep the children indoors and inactive. This is becoming frighteningly more evident in countries like Singapore and the Philippines, where only half of all students get proper exercise even once a week.
The good news, says the Journal of the American Medical Association, is that regular exercise can prevent or at least delay the onset of type II diabetes! More about exercise in another chapter.
Type II diabetes used to be called adult onset or maturity onset diabetes. Most cases of type II diabetes do begin in adulthood—most after the age of 40. Occasionally, however, a young person may get type II (non-insulin-dependent) diabetes or an older person may develop type I (insulin dependent) diabetes.
Is the “fairer sex” more likely to get type II diabetes than the male gender? Apparently not. In a national health survey taken in one Southeast Asian country, the number of men with diabetes was slightly higher than the number of women with the disease. Figures vary from country to country.
It appears that industrialization and the changes it has brought about in society may be a cause of diabetes, especially type II diabetes. Some of the chemical poisons or the viruses found in a specific community may trigger off the autoimmune processes which destroy the beta cells in the pancreas. Studies have shown that people who migrate to another country are likely to develop the same risk of diabetes as is found in their adopted country. Even moving to the cities appears to increase the risk of diabetes, likely because of changes in diet and other lifestyle habits.
Race and Ethnic Background
Certain races and population groups have a higher risk of getting diabetes. In Southeast Asia, the Indians have diabetes more commonly than any other group. Malays and Indonesians have the next highest incidence of diabetes, and the Chinese have the lowest rate. Even so, diabetes has doubled among the Chinese population of Singapore in the past eight years—a higher increase than in any other racial group. (In Singapore, among adults between the ages of 30 and 69, about 18 percent of the Indians, 14 percent of the Malays, and 11 percent of the Chinese already have diabetes.)
There is a third kind of diabetes, though it is much less common than types I and II. It is called gestational diabetes because it begins during pregnancy, which doctors call the gestational period.
If a woman has someone in her family who already has diabetes, she is a more likely candidate for gestational diabetes. If she is over 30 years old, and especially if she is overweight, she has a greater chance of developing diabetes during her pregnancy.
Pregnancy is a time of additional stresses to the human body. The body may fail to produce enough insulin to meet the need ruing this time. Approximately one percent of all women may develop symptoms of diabetes during the last half of pregnancy.
In 98 percent of the cases, the diabetes will go away once the baby is born. However, a woman who has developed gestational diabetes during one pregnancy will most likely to develop it again during later pregnancies. She also has a higher chance of developing diabetes later in life.
We have just looked at several of the suspected causes of diabetes. In rare circumstances, however, a person may also become diabetic because of other serious stresses on the body. Whenever the pancreas is damaged by infection or injury, there is a possibility of diabetes developing. Certain drugs may cause damage which will result in diabetes. Alcoholism may also cause an inflammation of the pancreas which could lead to the destruction of the insulin-producing beta cells.
Does sugar cause diabetes, as I thought when I was a child? There is not yet any real evidence one way or the other. Some scientists argue that it is only a common myth that diabetes is caused by eating a lot of sugar. Others say, “We know that sugar does cause diabetes—scientists just haven’t proven it yet!”
One nutrition expert says that sugar clogs the system and interferes with the working of the living machine—the body.
The Diabetic Societies of Singapore, Malaysia, and the Philippines admit that they don’t yet have all the answers, but they state that heredity, along with overeating—especially sugar and refined sugar products—increases your chances of having a high blood sugar. The extra sugar in the diet causes stress to the pancreas, and that could well lead to diabetes.
One thing we do know is that eating sweets and sugary foods does increase the amount of sugar (glucose) in the blood. A normal, healthy body can cope with a certain amount of sugar. But if you already have a hereditary tendency toward diabetes, if you are obese or physically inactive or have high blood pressure, or if your pancreas has been weakened by any of the possible causes mentioned above, eating that extra sugar may be hazardous to your health.
More research still needs to be done before we can say for sure what does or does not cause diabetes. And only as we learn the causes will we be able to work more toward the prevention
Meanwhile, as we wait for all the answers from medical science, we can strive to have the healthiest lifestyle possible.