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IN THIS CHAPTER

❯❯ Getting to the bottom of the causes, symptoms, and types of diabetes

❯❯ Knowing and modifying your risk factors and receiving a diagnosis

❯❯ Discovering how regulating carb intake is part of the treatment

Twenty-nine million Americans have diabetes. About 90–95 percent have type 2 diabetes, while 5–10 percent have type 1 diabetes. A couple other forms of diabetes make up a smaller percentage of cases. Eighty-six million American adults – over one-third of the population – have prediabetes, a condition of elevated glucose levels but not yet a diagnosis of diabetes.

If you rewind the clock by 50 to 100 years, diabetes was not nearly as prevalent as it is today. The societal trend is that Americans are now heavier and less active than our ancestors were a few generations ago. Being overweight and physically inactive are key risk factors for developing prediabetes and type 2 diabetes. It is now predicted that by the year 2050, one out of every three adults will have diabetes. It’s time to turn those trend lines around.

The Centers for Disease Control and Prevention (CDC) say, “Obesity-related conditions including heart disease, stroke, and type 2 diabetes are among the leading causes of preventable death.” Very convincing studies from all around the globe show that lifestyle interventions can delay or prevent diabetes. Those lifestyle interventions are also at the core of treating diabetes and are focused on improving dietary patterns, exercise habits, and weight management.

Diabetes can go undetected for many years, so screening is critically important. The CDC estimates that 25 percent of people with blood-glucose levels in the diabetes range remain undiagnosed, and an alarming 90 percent of people in the prediabetes range don’t realize that their glucose levels are elevated. This chapter identifies the risk factors and potential symptoms of diabetes, the diagnostic and classification criteria, and where to go next if you’re diagnosed.

Wrapping Your Brain around Diabetes and Related Conditions

We rely on foods to provide our bodies with energy, vitamins, minerals, and essential nutrients. On the most basic level, food and water are required for survival, but food is so much more than just a way to survive. We savor and enjoy food. We have cultural traditions, family recipes, and memories associated with food. Friends and relatives socialize around dinner tables and celebrate holidays and special occasions over meals.

When you’re diagnosed with diabetes, the focus on food shifts, and the next thing you know you are being asked to read food labels and break out the measuring cups. Your vocabulary expands to include the words “pancreas,” “insulin,” “carbohydrate,” and “blood glucose.” The good news is diabetes is manageable, now more than ever before. The first step in successfully managing your diabetes is to understand how the body is supposed to work and what has gone awry if you’ve developed diabetes. The following sections cover these topics.

Seeing how the body is supposed to process carbs

Human bodies need fuel to function. Glucose is the primary fuel source for the brain and red blood cells. It is also the preferred fuel source for muscles. Carbohydrate-containing foods provide glucose through the process of digestion and absorption. Glucose travels throughout the body via the bloodstream to all awaiting organs, tissues, and cells. For more on that process, see Chapter 4.

When all systems are working properly, a hormone called insulin helps the glucose move from the bloodstream into the cells where it’s burned for energy. The pancreas is the organ that makes and secretes insulin. Think of insulin as a “key” that has to unlock the cells to allow the glucose in. Insulin is supposed to bind to an insulin receptor on the surface of the cell. Once the insulin and the receptor are coupled, then the glucose may enter the cell. See Figure 2-1.

© John Wiley & Sons, Inc.

FIGURE 2-1: Insulin allows glucose to enter the cell.

If you have diabetes, it means either you don’t make enough insulin, or the insulin you make simply doesn’t work effectively. The next section elaborates further.

Discovering what causes diabetes

The surface of the pancreas has insulin-producing cells called beta-cells or islet cells. In the case of type 1 diabetes, the beta-cells are destroyed so they are no longer able to produce insulin. Without insulin, glucose cannot properly nourish the body.

Prior to 1921 when insulin was first discovered, people with type 1 diabetes didn’t survive very long. Initially insulin was harvested from cattle and pig pancreases and injected into humans. It wasn’t perfect and it caused allergic reactions, but people lived. In the 1970s genetically “human” insulin was produced in the lab and became widely available. Fast forward to today: There are numerous types of insulin and advanced technologies for administering them. Researchers around the globe continue to make progress in leaps and bounds, and they likely won’t stop until they find a cure.

Type 2 diabetes is a state of “insulin resistance.” People with type 2 are able to make insulin, but the insulin isn’t fully effective. It’s similar to having a key made for your front door, but when you attempt to use it, you are frustrated to find out that it doesn’t work smoothly. The key is there, the lock is there, but it takes persistence and jiggling and coaxing until finally the door opens. That’s the case with type 2 diabetes. The insulin is there and the insulin receptor is there, but the cell isn’t responding properly. Glucose uptake is delayed due to insulin resistance, so blood-glucose levels rise.

Insulin resistance precedes the onset of type 2 diabetes. Long before the diagnosis, the pancreas responds to rising blood-glucose levels by working harder to produce extra insulin. The pancreas works overtime because insulin levels have to rise higher than normal in order to manage glucose levels. Eventually the pancreas tires out and the beta-cells can no longer keep up the pace, so blood-glucose levels rise into diabetic ranges. (When glucose levels rise high enough, you may have symptoms, but not always. Symptoms are explained in the next section.)

Noticing the symptoms of diabetes

With insufficient amounts of insulin or insulin that doesn’t work properly, glucose can’t effectively get into the cells. Instead, the glucose accumulates in the bloodstream. Blood is filtered through the kidneys. Kidneys dispose of some of the excess glucose by removing it from the blood and dumping it into the urine. The bladder fills more quickly, which leads to frequent urination. Because the calories from glucose are flushed down the toilet, the cells aren’t fed as much and weight loss may occur.

There’s an interesting history behind the naming of the disease. The Greeks called it Diabetes Mellitus. Diabetes means “a siphon,” which refers to the excessive urination associated with the disease. Mellitus means “like honey,” which refers to the sweet smell and taste of the urine. Doctors in ancient Greece relied on their sense of taste and smell to make the diagnosis.

Symptoms are associated with uncontrolled diabetes. However, some people are asymptomatic, so diabetes can brew undetected for many years. In fact, some people are diagnosed with diabetes after developing a complication associated with uncontrolled, long-duration diabetes. It is important to have standard screening protocols for those at risk. Identifying risk factors and screening criteria are addressed later in this chapter.

The common symptoms associated with elevated blood glucose include

❯❯ Increased urination: This occurs because the kidneys are dumping some of the excess glucose into the urine.

❯❯ Thirst: Frequent urination can lead to dehydration, which triggers thirst.

❯❯ Hunger: The result is hunger as glucose is lost in the urine instead of being available to feed the cells and tissues. Additionally, when cells aren’t fed, muscles and body fat break down to provide an alternate fuel source. The body can break itself down to feed itself, which can lead to weight loss.

❯❯ Additional symptoms: These may include fatigue, blurred vision, tingling or numbness in feet and hands, yeast and fungal infections, and wounds that are slow to heal.

• When glucose isn’t used properly, the body lacks its main energy supply, which may result in fatigue or weakness.

• Blurry vision is usually temporary. It’s caused by glucose accumulating in the lens of the eye, which in turn causes fluid retention and swelling of the lens. Once glucose levels are controlled, the lens goes back to its usual shape and vision should improve.

Do not buy a new pair of glasses when your blood glucose is out of control. The lens of the eye may be temporarily misshapen due to concentrated glucose levels, and that can alter vision. Your eye specialist should evaluate your baseline vision once your glucose levels have stabilized in the near normal range.

• Uncontrolled diabetes can lead to nerve damage. Peripheral neuropathy, which refers to the nerves farthest from the brain and spinal cord, can cause tingling, burning, pain, or numbness in the feet or hands.

• High blood glucose means more sugar is available for yeast and bacteria to thrive on, so infections can fester.

• Healing may be impaired because the body’s immune system is compromised when glucose is out of control.

The symptoms associated with diabetes are not diagnostic and are sometimes related to other medical conditions. Discuss all medical concerns with your healthcare providers. Diabetes screening protocols are based on risk factors including weight and age and are clarified later in the chapter.

Distinguishing the types of diabetes

There are several types of diabetes. The suggested treatment depends upon the type. The vast majority of people have type 2 diabetes. Some people with type 2 diabetes can achieve control through diet and exercise modifications, while others need to add one or more oral medications. Everyone with type 1 diabetes and some people with type 2 diabetes require insulin.

Type 1 diabetes

Type 1 diabetes is an autoimmune disease. The body’s immune system, which is supposed to fight off bacteria, mistakenly destroys the insulin-producing beta-cells of the pancreas. People with type 1 diabetes no longer make insulin, so they must take insulin to live.

In the past this form of diabetes was called juvenile diabetes, insulin-dependent diabetes, or IDDM (short for insulin-dependent diabetes mellitus). The preferred term is type 1 diabetes, which may be abbreviated T1DM or T1D. The old terms don’t hold true for all cases. Not all kids with diabetes have type 1; there are many adolescents with type 2 diabetes. Insulin is used to treat other forms of diabetes, not just type 1. While it is true that type 1 diabetes is most often diagnosed when a person is below the age of 20, some adults are diagnosed with type 1 diabetes in their 20s, 30s, 40s, and even later.

Blood tests can determine whether the diagnosis is type 1 diabetes by detecting autoimmune markers in the blood. Another lab test called C-peptide estimates the amount of insulin being produced. (Find out more about diagnosing diabetes later in this chapter.)

Type 2 diabetes

Type 2 diabetes is due to insulin resistance. People with type 2 diabetes make insulin, but the insulin doesn’t work very well. Their own cells are resistant to the action of their insulin. Type 2 diabetes is due to a progressive insulin deficiency imposed on top of the initial insulin resistance.

Previously it was called adult-onset, non-insulin-dependent diabetes, or NIDDM (non-insulin-dependent diabetes mellitus). The current standard is to call it type 2 diabetes, which can be abbreviated T2DM or T2D. Unfortunately, type 2 diabetes often occurs alongside of high blood pressure and dyslipidemia (abnormal blood fats). A major shift must take place in the lifestyle of Americans to turn this trend around.

Prediabetes

Prediabetes is when blood-glucose levels are above normal but not yet in the range of diabetes. One in three American adults has blood-glucose levels in the prediabetes range. Up to 90 percent of them don’t know it. Prediabetes can lead to type 2 diabetes within five to ten years. The good news is that studies clearly show that progressing to type 2 diabetes isn’t inevitable. Weight loss of roughly 5–10 percent of starting weight coupled with moderate exercise of at least 150 minutes per week reduces the risk by up to 58 percent. Early detection and intervention may return blood-glucose levels to near normal ranges.

Gestational diabetes

Gestational diabetes is typically diagnosed in the second or third trimester of pregnancy. Pregnancy hormones interfere with the way insulin works by inducing a state of insulin resistance. As the pregnancy progresses, the mother’s pancreas has to work harder to make enough insulin to keep blood-glucose levels controlled. Some women simply can’t keep up with the demand, and they get diabetes during pregnancy, which resolves after delivery. Gestational diabetes is abbreviated as GDM (gestational diabetes mellitus). Women should be screened for GDM at 24 to 28 weeks of pregnancy. GDM also indicates a risk for developing type 2 diabetes in the future. (See Chapter 17 and the nearby sidebar “Diabetes and pregnancy” for more information.)

Other forms of diabetes

Other forms of diabetes make up only a small fraction of the cases of diabetes. These forms include the following:

❯❯ Neonatal diabetes occurs within the first six months of life and can be transient or permanent. Genetic testing is needed to clarify the defect, because some babies are best treated with oral medications while others require insulin.

❯❯ Cystic fibrosis–related diabetes (CFRD) can affect as many as half of the adults and 20 percent of the children who have cystic fibrosis. Insulin is the therapy of choice for CFRD.

❯❯ Maturity-onset diabetes of the young (MODY) is inherited and caused by any number of different chromosomal mutations. Treatment depends upon the specific genetic defect, so testing is required to clarify the diagnosis.

DIABETES AND PREGNANCY

Diabetes during pregnancy is considered a high-risk pregnancy. It is imperative for women with type 1 and type 2 diabetes to have tightly controlled blood-glucose levels prior to becoming pregnant. Uncontrolled diabetes can have devastating consequences. When maternal glucose levels are elevated, the extra glucose readily passes to the baby and that can cause big problems. High blood glucose in the first trimester increases the risk of birth defects and miscarriage. Gestational diabetes doesn’t develop until later in the pregnancy, so birth defects aren’t a concern with GDM.

There are late-pregnancy risks that apply to women with type 1, type 2, and gestational diabetes. High glucose in the second half of the pregnancy can cause the baby to grow too big, which makes for a riskier delivery for both baby and mom. Uncontrolled glucose levels also increase the risk of preeclampsia and stillbirth. Stringent glucose control throughout the entire pregnancy is critical. Women with diabetes who are of childbearing age should have preconception counseling. Some medications are not safe for the baby and thus must be discontinued prior to conception, including meds used to treat hypertension and cholesterol. Have a discussion with your healthcare provider. For more information on managing diabetes during pregnancy, see Chapter 17.

Recognizing Diabetes Risk Factors and Getting Diagnosed

The onset of type 1 diabetes tends to be sudden and come as a complete surprise. Prediabetes and type 2 diabetes can go undetected for years. Early diagnosis and intervention improve outcomes. I address screening protocols and diagnostic testing in the following sections.