Getting the lowdown on blood glucose

Diabetes is a disorder in which the amount of glucose, also called sugar, is too high in the blood. When you were diagnosed with type 2 diabetes, you were probably told that your blood glucose was sky high. But why would your blood glucose be high?

It all comes down to eating — that amazing topic that everyone likes to obsess about. When you eat food, your body breaks that food down into glucose, and then the glucose travels in your bloodstream to waiting cells. That glucose really wants to get out of your blood and into your cells because that’s how you get energy. That’s the goal!

Insulin is a hormone that helps move glucose from your blood to inside your cells. However, people with type 2 diabetes don’t make enough insulin or aren’t as sensitive to that hormone. Therefore, the glucose gets trapped in the blood and can’t get inside your cells. Then high blood glucose — diabetes — happens.

Glucose is just a simple form of carbohydrate. The simplest carbohydrates are sugars, and the simplest sugar is glucose. It’s your body’s main source of energy, used to power everything from getting up in the morning to taking your dog for a walk. Is it blood glucose or blood sugar? Actually they’re the same thing. Blood glucose is simple sugar. So, you may hear people say their “sugars” are too high or their blood glucose is too high. Blood glucose is the more technical term; sugar is the more colloquial term. We use blood glucose, or simply glucose, in this book.

The mighty hormone insulin

You’ve probably heard of insulin, and you may associate it with injections or an insulin pump. We usually think of that as the synthetic or man-made medication. But the hormone in your body is also insulin. And it’s one of the most important hormones for helping you metabolize your food and get energy.

Specialized beta cells in the pancreas make insulin. The pancreas, which is totally essential and underappreciated (until it stops working), is little, about 6 inches long, and sits right behind your stomach (see Figure 1-1).

The pancreas has islet cells that include both beta cells, which make insulin, and alpha cells, which make another hormone called glucagon. Both insulin and glucagon are important for metabolizing food.

Beta cells are the only cells that make insulin. In type 2 diabetes, several things are happening with those beta cells:

• The beta cells don’t work well. They don’t make as much insulin as they’re supposed to.
• There may be fewer beta cells than usual.
• The beta cells that are making all the insulin get burned out (super tired) and eventually make less insulin. It’s a cycle in which insulin production can get worse over time.

At the same time that beta cells are struggling in the pancreas, another crazy thing happens: Cells in your body become less sensitive to insulin. So, even though the insulin may be sitting right next to the glucose by a cell, saying, “Hey, let us in!” your cell doesn’t let them in. Instead, your cells need more insulin than ever before to let those glucose molecules inside. This is called insulin resistance or decreased insulin sensitivity.

It’s a double whammy: Your pancreas makes less insulin, and yet you need more insulin than ever before. It’s not a good combination.

If your body doesn’t make enough insulin or if you have insulin resistance, your glucose can’t get inside your cells and builds up in your blood. This is called high blood glucose. It’s the key factor that defines diabetes.

Scientists are still trying to figure out why beta cells fail or die — and also why the body becomes less sensitive to insulin. If they can get to the bottom of those questions, we’re on our way toward a cure for type 2 diabetes.

In the meantime, scientists know that insulin sensitivity can be improved by exercise. Just a short bout of exercise can improve insulin sensitivity for up to 24 hours. It’s another amazing effect of breaking a sweat besides burning calories.

Insulin is a hormone that helps your cells use glucose for energy. It’s made by beta cells in the pancreas. People with type 2 diabetes may not make enough insulin or may not be as sensitive to insulin — or both.

Don’t forget glucagon

Your pancreas makes another hormone, glucagon, which works together with insulin to turn food into energy (refer to Figure 1-1). Glucagon works very closely with the liver by stimulating glucose stored inside it. This is an essential step when you need extra energy and you’re not eating. For example, you might release glucagon when you exercise or if you need energy between meals. As you can see, it’s a delicate balance to get energy from the foods you eat, but also have access to energy whenever you need it.

High blood glucose is not good

The bottom line is that people with type 2 diabetes have too much glucose in their blood.

High blood glucose can create problems in the short term and long term. It’s so important because it can make you feel crummy from time to time, but it can also cause dangerous complications down the road.

As blood glucose levels rise, your body tries to flush out extra glucose in your blood by filtering it through your kidneys and out through your urine. That’s why people with undiagnosed or out-of-control diabetes pee a lot. So much peeing causes people to feel thirsty, dehydrated, and tired. Dehydration can also blur vision.

However, high blood glucose may not cause these symptoms in everyone. Or sometimes the symptoms just aren’t that noticeable. People can walk around for years without any symptoms or knowledge that they have high blood glucose and diabetes.

In the long term, high blood glucose damages blood vessels and nerves. The damage can lessen blood flow throughout your body, from your heart to your head to your feet. This, in turn, can lead to complications like eye disease, heart disease, stroke, and kidney failure. You find out more about complications in Chapter 8.

The great news is that you can take active steps to lower your blood glucose by eating wholesome foods, exercising, losing weight, and taking prescribed medications. You don’t have to experience problems in the short or long term. The most important thing to remember is that you can take control of your blood glucose and diabetes.

Paying attention to blood pressure

Two out of every three people with diabetes have high blood pressure or take medications to lower it. That’s a big number. Blood glucose and blood pressure go hand in hand. Why? Because they’re both related to your blood vessels.

High blood glucose can damage blood vessels, causing them to narrow and inhibit the flow of blood. This in turn can cause high blood pressure, which can lead to further damage such as a heart attack, stroke, or kidney failure.

Also, diabetes and high blood pressure share similar risk factors, including smoking, obesity, and eating foods high in saturated fats. For example, if you’re overweight and smoke cigarettes, it’s a double whammy on your body.

High blood pressure doesn’t have any symptoms. You won’t know you have high blood pressure until you have your blood pressure checked by your healthcare provider. Make sure you have it tested every time you visit your doctor or nurse.

Most people with diabetes will have a goal of less than 140 mmHg for systolic blood pressure (the top number) and less than 90 mmHg for diastolic blood pressure (the bottom number) to reduce the risk of cardiovascular disease and other complications.

Type 1 diabetes

Type 1 diabetes is another common type of diabetes. It usually comes on much more severely than type 2 diabetes. In general, people with type 1 diabetes have to take insulin right away to survive because their bodies don’t make any insulin. They have to take insulin for the rest of their lives. This is unlike type 2 diabetes, which has a more gradual progression.

Type 1 diabetes used to be called juvenile diabetes because it typically occurs in children. However, adults can also develop type 1 diabetes. Type 1 diabetes is an autoimmune disease in which the body destroys its own beta cells and, therefore, can no longer produce insulin. Of all the people with diabetes, about 5 percent have type 1 diabetes. (The “Type 1 or type 2?” sidebar explains how doctors determine whether you have type 1 or type 2 diabetes.)

Gestational diabetes

Gestational diabetes is a type of diabetes that occurs during pregnancy. It usually goes away after giving birth but gives moms and their babies a lifetime risk of developing type 2 diabetes. Women with gestational diabetes are more likely to someday have type 2 diabetes. Their children are also more likely to develop type 2 diabetes and be obese.

Women with gestational diabetes can take medications, eat healthy foods, and exercise to manage their blood glucose during pregnancy. Uncontrolled blood glucose during pregnancy can increase the risk of preeclampsia and injury during birth because babies are large. When you’ve had gestational diabetes, you have a two in three risk for it in subsequent pregnancies.

Gestational diabetes is different from already having type 2 diabetes and becoming pregnant. Women with preexisting type 2 diabetes should try to have their blood glucose on target before they become pregnant. They also need to exercise, eat healthy foods, and often take medications to manage their blood glucose during pregnancy.

All pregnant women should be tested for gestational diabetes during the 24th to 28th week using the oral glucose tolerance test (see Chapter 9 for more details on tests to diagnose gestational diabetes). Then women with gestational diabetes should get a test for type 2 diabetes 4–12 weeks after giving birth and every 3 years thereafter.

Other types of diabetes

Type 1, type 2, and gestational diabetes are the main types of diabetes. However, they’re not the only ones. Other forms of diabetes occur because of mutations in single genes. You can inherit these gene mutations, or they can occur out of the blue. Maturity-onset diabetes of the young (MODY) and neonatal diabetes mellitus are two of the most common forms.

Cystic fibrosis–related diabetes is another type of diabetes common in people with cystic fibrosis, which occurs because of scarring of the pancreas. This also destroys beta cells and stops insulin production.

Prediabetes

Prediabetes is another term you’ve probably heard alongside type 2 diabetes. And it’s exactly what it sounds like. Prediabetes is a higher than normal blood glucose level that isn’t high enough to be diabetes. One out of three American adults has prediabetes, although many don’t know they have it; nine out of ten Americans who have prediabetes are undiagnosed.

Why does prediabetes matter? Well, it turns out that making changes to the foods you eat or exercising more can reduce your risk for diabetes. This is especially true for people with prediabetes. Finding out you have prediabetes can be a wakeup call to make changes to your lifestyle and health.

In one study called the Diabetes Prevention Program, people with prediabetes who lost 5–7 percent of their body weight through changes to diet and exercise reduced their risk of developing diabetes by 58 percent during the 3-year course of the study. This was a landmark study that showed that people at risk for type 2 diabetes can make changes to prevent or delay the disease.