Can vitamin B12 supplementation improve the symptoms of diabetic peripheral neuropathy in patients with diabetes?

This review assessed the effect of vitamin B12 supplementation on clinical outcomes when used alone or combined with other treatments for diabetic peripheral neuropathy (PN). The authors concluded that a greater reduction of PN symptoms occurred with the use of B12 supplementation alone or in combination with other treatments compared to placebo.

Patients with diabetes often develop PN. PN is nerve damage caused by high blood glucose levels. It is the most commonly occurring diabetic complication. PN affects the legs and feet, followed by the hands and arms. Symptoms may be mild to painful. They range from a pinprick, needle, or burning feelings, hot or cold sensations, numbness, inability to detect temperature changes, muscle weakness, and sensitivity to touch.

Vitamin B12 deficiency has been associated with diabetic PN. Evidence suggests a possible link between the use of antidiabetic medicines such as metformin and PN. A lack of vitamin B12 is also believed to worsen the symptoms of neuropathy. However, there is a need for an updated overview comparing the use of vitamin B12 (methylcobalamin) supplementation alone or in combination therapy versus placebo for diabetic PN.

This review assessed 6 articles that included 689 patients with diabetic PN. Patients were treated with either vitamin B12 alone (159) or in combination with other vitamins or minerals (182) or with a placebo (348). Neuropathic symptoms were evaluated.

Patients that received vitamin B12 supplementation had a greater decrease in neuropathic symptoms compared to those in the placebo group. Vitamin B12 had no significant effect on vibration perception. Patients given vitamin B12 had greater reductions in pain compared to those that received a placebo.

The study suggested improvements in neuropathic symptoms and pain reduction in patients with diabetic PN that received vitamin B12 supplementation alone or in combination.

The analysis did not consider the influence of age, gender, underlying diseases, and other unmeasured factors on the results. Only two studies used vitamin B12 alone while others used combination treatments that included vitamin B12. Most of the studies analyzed had a small number of participants.