✔ Fatigue: Without sufficient insulin, or with ineffective insulin, glucose can’t enter cells (such as muscle and fat cells) that depend on insulin to act as a key. (The most important exception here is the brain, which does not need insulin to extract glucose from the blood.) As a result, glucose can’t be used as a fuel to move muscles or to facilitate the many other chemical reactions that have to take place to produce energy. A person with diabetes often complains of fatigue and feels much stronger after treatment allows glucose to enter his or her cells again.
✔ Weight loss: Weight loss occurs among some people with diabetes because they lack insulin, the builder hormone. When the body lacks insulin for any reason, the body begins to break down. You lose muscle tissue. Some of the muscle converts into glucose even though the glucose can’t get into cells. It passes out of your body in the urine. Fat tissue breaks down into small fat particles that can provide an alternate source of energy. As your body breaks down and you lose glucose in the urine, you often experience weight loss. However, most people with diabetes are heavy rather than skinny. (I explain why in Chapter 3.)
✔ Persistent vaginal infection among women: As blood glucose rises, all the fluids in your body contain higher levels of glucose, including the sweat and body secretions such as semen in men and vaginal secretions in women. Many bugs, such as bacteria and yeast, thrive in the high-glucose environment. Women begin to complain of itching or burning, an abnormal discharge from the vagina, and sometimes an odor.
A study in the November 2007 issue of Diabetes Care, however, showed that in a group of over 15,000 people being treated for diabetes, 44 percent of people with type 2 diabetes reported not one of the symptoms above in the previous year when given a questionnaire. It is no wonder that a third of people with diabetes don’t know they have it.
Frequent thirst and urination are the most commonly recognized symptoms of diabetes, but diabetes mellitus is not the only condition that causes these symptoms. Another condition in which fluids go in and out of the body like a siphon is called diabetes insipidus. With this condition, the urine is not sweet. Diabetes insipidus is an entirely different disease that you should not mistake for diabetes mellitus. Diabetes insipidus results when a hormone in the brain called antidiuretic hormone is missing or when the kidneys can’t properly respond to antidiuretic hormone. This hormone normally helps the kidneys prevent the loss of a lot of the water in the body. Other than the name diabetes, this condition has nothing to do with diabetes mellitus.
Tracing the History of Diabetes Treatment
More than 2,000 years ago, people writing in China and India described a condition that must have been diabetes mellitus. The description is the same one that the Greeks and Romans reported – urine that tasted sweet. Scholars from India and China were the first to describe frequent urination. But not until 1776 did researchers discover the cause of the sweetness – glucose. And it wasn’t until the 19th century that doctors developed a new chemical test to actually measure glucose in the urine.
Later discoveries showed that the pancreas produces a crucial substance that controls the glucose in the blood: insulin. Since that discovery was made, scientists have found ways to extract insulin and purify it so it can be given to people whose insulin levels are too low.
After insulin was discovered, diabetes specialists, led by Elliot Joslin and others, recommended three basic treatments for diabetes that are as valuable today as they were in 1921:
✔ Diet (see Chapter 8)
✔ Exercise (see Chapter 10)
✔ Medication (see Chapter 11)
Although the discovery of insulin immediately saved the lives of thousands of very sick individuals for whom the only treatment had been starvation, it did not solve the problem of diabetes. As these people aged, they were found to have unexpected complications in the eyes, the kidneys, and the nervous system (see Chapter 5). And insulin didn’t address the problem of the much larger group of people with diabetes now known as type 2 (see Chapter 3). Their problem was not lack of insulin but resistance to its actions. (Fortunately, doctors do have the tools now to bring the disease under control.)
The next major leap in the effort to treat diabetes, occurring in 1955, was the discovery of the group of drugs called sulfonylureas (see Chapter 11), the first drugs that could be taken by mouth to lower blood glucose levels. But even while those drugs were improving patient care, the only way to know if someone’s blood glucose level was high was to test the urine, which was entirely inadequate for good diabetic control (see Chapter 7).
Around 1980, the first portable meters for blood glucose testing became available. For the first time, doctors and patients could relate treatment to a measurable outcome. This development has led, in turn, to the discovery of other great drugs for diabetes, such as metformin, exenatide, and others yet to come.
If you are not using these wonderful tools for your diabetes, you are missing the boat. You can find out exactly how to use portable meters in Part III.
Tracking diabetes around the world
Diabetes is a global health problem. Type 2 diabetes is especially prevalent where obesity is common. In 2008, more than 1.5 billion people were overweight (body-mass index greater than 25 kilograms/meter squared – see Chapter 7) and 500 million people were obese (body-mass index greater than 30) in the world. Currently 366 million people have diabetes. Diabetes is most concentrated in areas where large food supplies allow people to eat more calories than they need, causing them to develop excessive fat. Several different types of diabetes exist, but the type usually associated with obesity, called type 2 diabetes (see Chapter 3), is far more prevalent than the other types.
Another reason diabetes cases have continued to grow in number throughout the world is that the life span of the population is increasing. What’s the connection? Well, as a person ages, his or her chances of developing diabetes increases greatly. Along with obesity, age is a major risk factor for diabetes. (See Chapter 3 for more risk factors.) So as other diseases are controlled and the population in general gets older, more diabetes is being diagnosed.
One very interesting study traced people of Japanese ancestry as they went from living in Japan to living in Hawaii to living in the United States mainland. In Japan, where people customarily maintain a normal weight, they tended to have a very low incidence of diabetes. As they moved to Hawaii, the incidence of diabetes began to rise along with their average weight. On the U.S. mainland, where food is most available, these Japanese had the highest rate of diabetes of all.
In general, as people migrate to areas of the world consuming a Western diet, not only the number of calories they consume but also the composition of their diets changes. Before they migrate, they tend to consume a low-fat, high-fiber diet. After they reach their destination, they adopt the local diet, which tends to be higher in fat and lower in fiber. The carbohydrates in the new diet are from high-energy foods, which do not tend to be filling, which in turn promotes more caloric intake.
Explaining the Obesity (and Diabetes) Epidemic
Many changes explain the epidemic of obesity and diabetes that began to explode in the 1950s and ’60s. Here are some of them:
✔ The availability of fast-food restaurants and vending machines
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