Where does diabetes affect the body?

Diabetes begins in the pancreas, where insulin is made. This is true for both type I diabetes and type II diabetes, even though the underlying causes are different.

Although diabetes begins in the pancreas, it affects every organ in the body. The reason is simple: every cell in the body needs energy to do its job, and that energy typically comes from blood sugar, which is processed by insulin. Thus, diabetes has the potential to affect every organ in the body.

Some complications from diabetes are more common than others, and some are more dangerous, and so they typically get the most attention.

Cardiovascular disease is the life-threatening complication of diabetes. There's a lot of disagreement in the medical community over how, exactly, diabetes leads to an increase in cardiovascular disease. Some doctors and medical researchers believe that, except in rare cases of extreme high or low blood sugar, diabetes does not directly affect the heart and the blood vessels, and that the real problem comes from weight gain and obesity that often happens with diabetes. Other doctors and medical researchers believe that diabetes can alter the cells of the heart and the blood vessels, making it more likely that a heart attack or stroke can occur.

Next, damage to small blood vessels, including nerve damage (neuropathy), kidney damage (nephropathy), and eye damage (retinopathy). It is only in recent years that scientists have identified how diabetes causes damage to blood vessels. As this article summarized, diabetes changes the level of two enzymes that regulate the production of nitric oxide, which helps blood vessels relax. In diabetics, the higher levels of sugar and fat in the blood stream cause more oxidative stress and more inflammation. Those two issues are alone enough to increase the risk of blood complications, but, in addition, diabetes also causes lower levels of nitric oxide, which makes the oxidation, free radicals, and inflammation even worse.

Other complications include increase risk of injuries in the hands and feet, hearing loss, an increased risk of Alzheimer's, and an increased risk of several types of cancer.