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.
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.
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.
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.