When we eat, our bodies break food down into organic compounds, one of which is glucose. The cells of our bodies use glucose as a source of energy for movement, growth, repair, and other functions. But before the cells can use glucose, it must move from the bloodstream into the individual cells. This process requires insulin.
Insulin is produced by the beta cells in the islets of Langerhans in the pancreas. When glucose enters our blood, the pancreas should automatically produce the right amount of insulin to move glucose into our cells. People with type 1 diabetes produce no insulin. People with type 2 diabetes do not always produce enough insulin.