Glucose is an important source of energy for all cells in the body. The liver produces glucose from digested sugar and carbohydrate. Insulin is a hormone made by the pancreas. Insulin regulates the level of glucose in the bloodstream. Normally, the pancreas releases insulin into the bloodstream when the glucose level is elevated in the bloodstream after a meal. The insulin stimulates cells to use the glucose, which in turn, lowers the level of glucose in the bloodstream.

The two main causes of diabetes include:

• The pancreas does not produce enough insulin: without insulin, the cells are not stimulated to use glucose and glucose levels increase in the bloodstream.
• The cells do not respond to insulin: even if insulin levels are high, the cells will not use the glucose and glucose levels increase in the bloodstream.

Blood sugar is also called glucose. It is the most critical source of energy in the body. It is the only kind of energy used by the brain. Close regulation of glucose keeps blood levels high enough to supply the brain with fuel.

Blood glucose levels normally change during the day. Diet, physical activity and hormones such as adrenalin and insulin all affect blood glucose. Insulin controls the level of glucose in the bloodstream. It allows cells to use glucose. Without insulin, the glucose level rises in the bloodstream. However, the body cannot use it.

Many conditions can raise blood glucose. Others lower sugar levels. Hyperglycemia is when blood glucose is too high. Very high levels of glucose create acids in the blood, called ketoacidosis. Hypoglycemia means low levels of glucose. Diabetics can control their disease much better when they understand these conditions.