Glucose is used as fuel by every cell in the body. When glucose is eaten, it is absorbed into the blood from the small intestine. Once it reaches a cell, it must cross the fine membrane that forms the cell’s outer skin. This is normally impermeable to all substances, but insulin has the ability to combine with glucose and transport it across the membrane from the blood into the interior of the cell. Insulin is made by cells in the Islets of Langerhans in the pancreas, which sits in the centre of the abdomen.
Only 10% of diabetics suffer from this form of diabetes mellitus, which is caused by a lack of insulin production by the pancreas. Most people develop this type as a child or in early adult life.