To put it simply, diabetes is a condition in which there is too much sugar (glucose) in the blood.
We need glucose—it’s the primary source of energy that fuels the brain, red blood cells and muscles of the body. It’s when blood sugar levels rise too high that there’s a problem. When your fasting blood sugar is 126 or greater, you are considered to have diabetes. More than 26 million Americans have type 2 diabetes.
Diabetes is a disease of the pancreas, a 6-inch-long gland located near the stomach. The pancreas has two primary functions:
Its first function is to release into the stomach the various enzymes that allow us to digest foods.
Its second function is to release the hormones insulin and glucagon into the blood to keep the blood sugar level relatively constant. Insulin is an essential hormone that’s responsible for regulating the body’s carbohydrate and fat metabolism. It lowers blood sugar by moving glucose from the blood into the cells, and by pushing it into storage. Glucagon works in the opposite way from insulin. It triggers the breakdown of stored sugars in the liver to use as energy when blood sugar levels get low. More often than not our body is trying to lower our blood sugar to counteract that sugar-laden meal we just ate, so insulin tends to be the hormone we talk more about.
Because most foods contain some sugars (which are usually packaged as carbohydrates), blood sugar levels would fluctuate wildly if the pancreas was unable to keep them constant. This would be catastrophic to most organs and body functions. When the body loses the ability to lower blood sugar levels, it’s a phenomenon known as “insulin resistance.”
There are two types of diabetes:
Type 1 diabetes (previously called juvenile diabetes)—Only five to 10 percent of people with diabetes have type 1 diabetes. This autoimmune disease attacks the beta cells of the pancreas, where insulin is normally made. With type 1 diabetes, the beta cells become too damaged to produce insulin. As a result, glucose cannot be moved into the cells.
You can think of the process much like an oil refinery that refines crude oil into gasoline. Ground tanks then deliver that gasoline to gas stations, where it can be pumped into cars. In type 1 diabetes, the body acts as the refinery, breaking down carbohydrates into fuel—glucose (sugar).
However, that fuel can’t be pumped from the station into cars—the cells—because of faulty pumps (no insulin).
People with type 1 diabetes need to inject insulin to reduce their blood sugar levels. If they do not take insulin, their cells will die from starvation. Before scientists discovered insulin in 1922 and were able to turn it into an injectable form, the average life expectancy of a person with type 1 diabetes was six months.
Type 2 diabetes (previously called adult-onset, or non-insulin dependent diabetes)—Most of the time when we’re talking about diabetes, we’re discussing type 2 diabetes. People with type 2 diabetes also have elevated blood sugar, but their pancreas is able to produce insulin.
The fundamental difference between type 2 and type 1 diabetes occurs in the cells. With type 2 diabetes, a malfunction in the cells causes a myriad of problems. Although there is plenty of insulin in the blood, that insulin is unable to pull sugar into the cells to bring down blood sugar levels. The cells are already so overloaded with energy that they resist any attempts to add more sugar. To use the same analogy from before, the refinery works fine, sending the fuel (glucose) to be pumped out of the station tanks (blood), but when the car pulls up (the cell), it is already full.
The pancreas keeps pumping out insulin in an attempt to move the sugar from the blood into the cells. Eventually, the pancreas “tires out” from the hard work of trying to pump out extra insulin.
Despite all the glucose that is being stored in the cells, only a relatively small amount is being used for fuel. That’s why when you have diabetes, you always feel as though you don’t have enough energy, even though you actually have too much stored fat. You feel hungry, you’re tired, and your body doesn’t run well. You think you need more fuel, when what you really need is the right fuel.
With both type 1 and type 2 diabetes, high levels of sugar in the blood are what lead to complications. Later we’ll discover how to overcome the problem of high blood sugar to avoid these complications.