Maxy sez : Why Does Type 2 Diabetes Cause Your Feet to Go Numb?

  High blood sugar that's uncontrolled can lead to serious complications, like pain, numbness, and injury in the feet and legs.
By Jennifer Laskey   Medically Reviewed by Justin Laube, MD
If you’re concerned you may have neuropathy or if you experience cracks, pus, ulcers, or other signs of infection in your feet, please see your doctor.Chris Rout/Alamy

Numbness in the feet is a symptom of neuropathy or nerve damage, one of the most common long-term complications of type 2 diabetes. Neuropathy is caused by poor blood sugar control that persists over a long period of time.

“The higher the blood sugars and the longer they stay high, the greater the chance of the person developing neuropathy,” says Joel Zonszein, MD, director of the Clinical Diabetes Center at the University Hospital of the Albert Einstein College of Medicine, Montefiore Health System in the Bronx, New York.

“The nerves that get affected by high sugars tend to be the longest nerves in the body,” explains Dr. Zonszein. These nerves go from the spine to the toes, which is why the feet get affected before the arms or hands. Diabetic neuropathy also tends to be bilateral. “Both feet will be affected equally,” he says.

If blood sugar remains poorly controlled, it can lead to serious complications. In the feet, diabetic neuropathy can not only cause numbness but pain and injuries. It can change the shape of your feet, deforming them so they no longer fit into regular shoes. It can also dry out and damage your skin, cause calluses and ulcers on your feet, and interfere with circulation. The numbness also makes it hard to tell if there is a cut or injury which can increase your risk of infections and amputation.

People with diabetes are also at an increased risk for amputation. In 2010, approximately 73,000 non-traumatic lower-limb amputations were performed on adults (20 years or older) diagnosed with diabetes, according to the American Diabetes Association.

The good news is that most amputations are preventable when you manage your diabetes well, take good care of your feet, and wear proper footwear. If you have circulatory problems or you’ve already been diagnosed with neuropathy, you’ll benefit from seeing a podiatrist as well as your endocrinologist.

If you’re concerned you may have neuropathy or if you experience any redness, cracks, pus, ulcers, or other signs of infection in your feet, Zonszein advises going to see your doctor immediately.

The most effective way to prevent or delay diabetic nerve damage is to maintain good control of your blood sugar. Controlling blood pressure and cholesterol is also important. “Lipids [can] have an indirect effect on neuropathy,” says Zonszein.

He also emphasizes the importance of exercise and a healthy diet — and maintaining a healthy weight; which will address your overall cardiovascular and cholesterol health. “Patients who are overweight or obese tend to develop more neuropathy and more arthritic problems and pain in their feet because of the [extra] weight,” he adds.

Finally, your doctor may also want to check to make sure you don’t have a vitamin B deficiency. One of the most common medications used to treat diabetes, Metformin, can cause a deficiency in folic acid and vitamin B-12 in about 10 percent of the people who take it, warns Zonszein.

While maintaining good blood sugar control can help prevent or delay neuropathy, there is no cure once the nerves are damaged for a long period of time; the medications that are available only treat symptoms and slow the progression of the disease. However, researchers have seen some promising results in recent studies with mice. One published in the July 2015 issue of the Journal of Neurophysiology suggests that fish oil (specifically omega-3 fatty acids) may help reverse or slow the progression of diabetic neuropathy.

Overall, Zonszein says that he has been seeing less and less neuropathy, which he attributes to earlier diagnosis, better treatments, and patients working with their doctors to take charge of the disease. “People with diabetes are doing much better nowadays. We’re seeing complications less often and much later in the disease,” he says. “That’s an important message to patients."