What Is Type 1 Diabetes?

There are two major types of diabetes: type 1 and type 2. Each type causes high blood sugar levels in a different way.
In type 1 diabetes (which used to be called insulin-dependent diabetes or juvenile diabetes), the pancreas can't make insulin. That's because — for some reason doctors don't completely understand — the body's immune system attacked the pancreas and destroyed the cells that make insulin.
When a person has type 1 diabetes, the body is still able to get glucose from food, but the lack of insulin means that glucose can't get into the cells where it's needed. So the glucose stays in the blood. This makes the blood sugar level very high and causes health problems.
Once a person has type 1 diabetes, the pancreas can't ever make insulin again. To fix this problem, someone who has type 1 diabetes needs to take insulin through regular shots or an insulin pump.

Type 2 diabetes is different from type 1 diabetes. In type 2 diabetes, the pancreas still makes insulin. But the insulin doesn't work in the body like it should and blood sugar levels get too high.