Insulin is a hormone secreted by specialized cells in the pancreas in response to (among other things), increased blood glucose concentration. The primary role of insulin is to control the transport of glucose from the bloodstream into the cells. After consuming a meal, insulin enhances the uptake of the energy nutrients (amino acids, glucose, and fatty acids). Insulin helps maintain blood glucose within normal limits and stimulates protein synthesis, glucose synthesis in the liver and muscle, and fat synthesis.
Without insulin, or when insulin is ineffective, glucose regulation falters and the metabolism of energy-yielding nutrients changes. In diabetes, there is too much glucose in the blood. When glucose builds in the blood instead of going into the cells, it can cause two problems:
- Your cells may become starved for energy
- Over time, high glucose blood levels may harm your kidneys, heart, eyes or nerves
Type I Diabetes(a.k.a. Juvenile Onset Diabetes, Insulin-Dependant Diabetes) Insulin-dependant is caused by damage to the pancreas. The pancreas contains beta cells, which make insulin. With Type I diabetes, the deficiency of insulin is due to a decline in the number of beta cells the pancreas contains. It appears that certain genes make Type I diabetics more susceptible, but a triggering factor (usually a viral infection) sets it off. In most people with Type I diabetes, the immune system makes a mistake, attacking the beta cells and causing them to die. Without the beta cells, you cannot produce insulin. Glucose then builds up in the blood and causes diabetes.
Type II diabetes is the most common form of diabetes, with about 90% of diabetic falling into the Type II category. With Type II diabetes, glucose builds up in the blood – it’s not because not enough insulin is present, but probably because cells lose their insulin receptors and become less sensitive to insulin. Type II diabetes usually (though not always) occurs in individuals who are over 40 years of age and who are overweight.
Type II diabetes produces mild symptoms and can be controlled with a healthy diet, exercise and weight loss. Type II diabetics should also monitor their glucose levels to be sure they are maintaining healthy levels. In some cases, weight loss, diet, and exercise are not enough to control the glucose levels. In those cases, your physician may control your diabetes by prescribing diabetes pills or insulin shots.