Understanding Diabetes

You probably have an idea of what diabetes mellitus is, given that you are reading this book. But I have often found that many patients do not have an adequate grasp of their medical condition and thus have not been able to optimally participate in their own health care. So in this chapter I discuss the basics of diabetes.

Diabetes is a condition that affects more than 16 million Americans, of whom nearly one-third have yet to be diagnosed. Diabetes is characterized by elevated blood glucose, or sugar level (Harris et al. 1998). When a person without diabetes consumes food that contains carbohydrates, the main source for glucose in the blood, it is absorbed through the gastrointestinal tract and filters into the bloodstream. Once the sugar is in the blood, the body has a mechanism to recognize the level of blood sugar in the body. When a person eats, his blood sugar rises and the pancreas (an organ in the abdominal cavity) senses that the blood glucose level has risen and produces a substance called insulin. These cells in the pancreas allow glucose to flow through them via a special protein called GLUT-2 (glucose-transporter). When the glucose levels are higher than normal it is carried across GLUT-2 and starts a chain reaction that leads to the production of insulin, which is then released into the blood. You can think of insulin as the key to the door of the cell. When insulin is released from the pancreas into the blood, it comes in contact with cells in the peripheral tissues (muscle and fat); special pores (the doors) are unlocked, allowing glucose to flow into the cell, providing it with energy (see figure 1.1). The special doors in the peripheral tissues are made up of a special protein similar to those on the pancreas referred to as GLUT-4. This series of events is the mechanism that keeps the blood glucose at a normal level. In people with diabetes, the mechanism works abnormally. It is important to note that the brain and other cells have special proteins called GLUT-3 and GLUT-1 that are not dependent on insulin to function.

Figure 1.1 In a person without diabetes, insulin released from the pancreas acts as a key to open the cell door (GLUT-4) for glucose from the blood to enter.

Types of Diabetes

Diagnosing Diabetes

Gestational Diabetes

Treatment Basics