You have between one million and three million islets of Langerhans in your pancreas, the spongy, six-inch-long organ positioned behind your stomach. Without these clumps of cells, you'd be unable to produce insulin, the hormone that is released after you eat to mop up the sugar released by your food.

Most cases of type 1 diabetes occur when the body mistakenly sees the islet cells as a foreign invader and wrecks the thing.