Therefore, following a meal, blood sugar levels will rise significantly, and the islets will release a large amount of insulin. This insulin will cause body cells to take up the sugar, causing blood sugar to quickly return to its normal range. Once blood sugar is in the normal range, the islets will reduce the output of insulin to an idling state. In insulin-dependent diabetes, the islets are destroyed by the person's own immune system, which mistakenly identifies these essential cells as foreign invaders. Once the islets are killed, the ability to produce insulin is lost, and the overt symptoms and consequences of diabetes begin.
Some people think that injecting insulin is a cure for diabetes.
Unfortunately, it is not. Insulin allows a diabetic to survive, but the effects of crudely controlled blood sugar levels lead to the many devastating consequences of the disease. Unlike the precise matching of blood sugar and insulin levels that occurs normally, a diabetic's insulin injections cannot be precisely and continuously adjusted to maintain safe sugar levels. When an excess of injected insulin drives blood sugar levels too low, the diabetic risks an immediate dramatic reaction that may include confusion, loss of consciousness, coma, and even death. When injected insulin is below the required amount, blood sugar levels rise, leading to damage to eyes, kidneys, nerves, heart, and blood vessels.