The body gets glucose from the food you take, liver and muscles also supply your body with glucose. The blood carries the glucose to the cells throughout the body. Insulin, a chemical hormone, helps the body's cells to take up glucose. Insulin is produced by beta cells in the pancreas and released into the bloodstream.
If the body does not produce enough insulin or the insulin does not work as it should, glucose can not enter the cells of the body. In contrast, glucose should remain in the blood which causes an increase in the level of blood glucose. This high level of blood glucose cause a pre-diabetes or diabetes.