Diabetic neuropathy is damage to nerves and blood vessels caused by high blood glucose in diabetes. Damage to nerves can cause numbness in the hands, legs, and feet, urinary problems, sexual dysfunction, dizziness, and sharp, burning, or tingling sensations.
Diabetic neuropathies are a group of conditions that damages the nervous system of people with diabetes mellitus. They include distal symmetric polyneuropathy, diabetic peripheral neuropathy, diabetic autonomic neuropathy, cardiac autonomic neuropathy, and gastrointestinal neuropathies. These neuropathies can damage nerves and impair normal function in several organ systems, including the musculoskeletal system (especially the lower limbs and feet), the cardiovascular system, the gastrointestinal system, and the urogenital system (kidneys, bladder, and genitals). Distal symmetric polyneuropathy is the most common form of diabetic neuropathy, affecting the lower limbs and feet. Consequently, diabetic neuropathies reduce a person’s quality of life.
Diabetic neuropathies have several non-specific signs and symptoms that are also caused by other conditions. Therefore, diabetic neuropathy can go undiagnosed and untreated. Symptoms include numbness and tingling (paresthesia) in the fingers and toes, pain in the lower legs and feet, foot ulcers, lightheadedness/dizziness when standing up, erectile dysfunction, and gastrointestinal issues such as nausea, bloating, heartburn, diarrhea, and constipation. The signs are revealed with diagnostic tests showing poor nerve function (e.g., inability to sense a pinprick), impaired sensations (e.g., inability to distinguish hot from cold), orthostatic hypotension (a drop in blood pressure when standing up), resting tachycardia (high resting heart rate), and delayed gastric emptying (gastroparesis).
People who’ve had type 1 diabetes for at least five years, and all people with type 2 diabetes, are typically assessed annually for diabetic neuropathies. Assessment includes clinical tests exploring a person’s sensations of vibration, thermal changes, and pain. But, since diabetic neuropathies are a collection of several conditions with non-specific signs and symptoms, and since nondiabetic neuropathies can also occur in people with diabetes, the diagnosis of diabetic neuropathy is a process of exclusion — i.e., alternative causes of the presenting signs and symptoms are systematically ruled out before a final diagnosis.
There are no specific treatments for nerve damage, but lowering hyperglycemia (persistently high blood glucose concentrations) reduces the risk of diabetic neuropathy. Therefore, the main treatment is to improve blood glucose control using lifestyle behavior change (diet, exercise, and weight management counseling) and glucose-lowering drugs.
Since diabetic neuropathies can impair sensation, healthcare providers regularly examine patients’ feet for signs of damage to help prevent diabetic foot ulcers. To treat pain associated with diabetic neuropathies, pain-reducing medications (e.g., pregabalin or duloxetine) are used to improve quality of life. Reducing pain also helps patients increase their levels of daily physical activity, which improves blood glucose control.
Yes, research has examined the effects of several supplements on diabetic neuropathy. These include vitamin D, vitamin B12, L-carnitine, alpha-lipoic acid (ALA), and more. However, additional high-quality randomized controlled trials are needed to make firm conclusions concerning the effectiveness of supplements in reducing the risk of diabetic neuropathy or relieving its symptoms (e.g., pain).
Lifestyle behavior change improves blood glucose control in people with diabetic neuropathies. This includes an individualized diet to help patients lose weight and minimize postprandial (after-meal) rises in blood glucose concentrations.
Specific micronutrients might also play a role. For example, deficiencies in vitamin D  and vitamin B12  are associated with an increased risk of diabetic neuropathy. Therefore, people with diabetes who don’t consume vitamin D-containing foods (oily fish, egg yolks, liver, etc.), or who eat a plant-based diet that excludes meat, might be at a greater risk of diabetic neuropathy. However, studies are needed to test these hypotheses.
Aerobic exercise and sensorimotor training to improve motor control (balance, posture, etc.) can relieve some of the signs and symptoms of diabetic peripheral neuropathy. Furthermore, low-frequency electrical stimulation of the spinal cord (also known as neuromodulation therapy) can reduce pain associated with diabetic neuropathies. However, more high-quality randomized controlled trials are needed to draw conclusions about the efficacy and safety of neuromodulation therapy.