A new study published in the journal BMJ Open Diabetes Research and Care discovered that treatment with a single intramuscular dose of 600,000 IU of vitamin D in patients with painful diabetic neuropathy caused significant reductions in symptoms.
Diabetic neuropathy is a type of nerve disorder that can occur if a person has diabetes. High blood sugar can injure nerves throughout the body, but diabetic neuropathy most commonly affects nerves in the legs and feet. It often causes pain and numbness in the extremities, but may also cause problems in the gastrointestinal tract, urinary tract, blood vessels and heart.
Approximately 21% of the population is affected by painful diabetic neuropathy. Treatments for diabetic neuropathy are limited. The therapeutic effectiveness for all medications is at best near 50% pain relief. In addition, most of the medications are accompanied by unwanted side effects. This has left the medical community searching for new treatments.
A previous study suggested vitamin D supplementation may help treat diabetic neuropathy. The researchers found that weekly vitamin D supplementation of 50,000 IU for 8 weeks reduced symptoms but not disability. In an effort to confirm the treatment effect of vitamin D on diabetic neuropathy, researchers recently conducted a prospective open-labeled trial in Pakistan.
A total of 143 patients with type 1 or type 2 diabetes were included in the study. All patients received a single intramuscular dose of 600,000 IU of vitamin D3. Pain was assessed using three different questionnaires: The Douleur Neuropathique 4 (DN4), total McGill pain and Short Form McGill Pain Questionnaire (SFMPQ). The researchers wanted to compare pain severity before and after the administration of the vitamin D injection. Here is what they found:
- Average vitamin D levels increased from 31.7 ng/ml at baseline to 46.2 ng/ml at week 20.
- Total McGill pain score, DN4 and SFMPQ significantly decreased after vitamin D administration (p<0.001).
The researchers concluded,
“The administration of 600 000 IU of vitamin D results in a modest but significant increase in 25(OH)D levels measured at 20 weeks. This improvement in 25(OH)D levels was associated with an improvement in several independent measures of PDN, which became significant approximately 10 weeks after administration of vitamin D.”
The researchers noted that the average vitamin D levels of the patients at baseline was much higher than previous studies, indicating that a proportion had likely received vitamin D supplementation from their primary physician previously. This shows vitamin D supplementation has become a more widely accepted practice for diabetic patients.
Future studies should follow a randomized controlled trial design and use a daily dosage regimen.
Tovey, A. & Cannell, JJ. Research finds vitamin D to be a safe and effective treatment for painful diabetic neuropathy. The Vitamin D Council Blog & Newsletter, 2016.