Nerves carry messages back and forth between the brain and other parts of the body. All of your nerves together make up the nervous system.
Some nerves tell the brain what is happening in the body. For example, when you step on a tack, the nerves in your foot tell the brain about the pain. Other nerves tell the body what to do. For example, nerves from the brain tell your stomach when it is time to move food into your intestines.
Having high blood glucose for many years can damage the blood vessels that bring oxygen to some nerves. High blood glucose can also hurt the covering on the nerves, called myelin. Damaged nerves may stop sending messages. Or they may send messages too slowly or at the wrong times.
The causes of diabetic neuropathy are probably different, depending on the type of neuropathy a person has. Researchers are studying the effect of glucose on nerves to find out exactly how prolonged exposure to high glucose causes diabetic neuropathy. Nerve damage is likely due to a combination of:
- Metabolic factors, such as high blood glucose, long duration of diabetes, possibly low levels of insulin, and abnormal blood fat levels
- Neurovascular factors, leading to damage to the blood vessels that carry oxygen and nutrients to the nerves
- Autoimmune factors that cause inflammation in nerves
- Mechanical injury to nerves, such as carpal tunnel syndrome
- Inherited traits that increase susceptibility to nerve disease
- Lifestyle factors, such as smoking or alcohol use.