Vitamin D Supplementation in the Management of Painful Diabetic Peripheral Neuropathy: A Narrative Review

Abstract

Background: Painful diabetic peripheral neuropathy (DPN), a debilitating complication of diabetes mellitus (DM), significantly reduces quality of life. Vitamin D deficiency is common in patients with DM and has been associated with both the presence and severity of DPN. Objectives: This systematic review aims to investigate whether vitamin D supplementation improves neuropathic symptoms in patients with painful DPN. Study Design: A narrative review. Methods: A systematic literature search was conducted in MEDLINE (PubMed), the Cochrane Library, Embase, Scopus, and the Web of Science for English-language articles published through August 7, 2025. Studies were included if they evaluated the effects of vitamin D supplementation in patients with painful DPN. Results: Overall, 50 articles were identified through the database search. After screening titles and abstracts, 39 articles were excluded for not meeting the inclusion criteria. The remaining 11 articles were assessed for full-text eligibility. Finally, 7 studies were included in this review. Most of those studies reported improvements in pain scores, quality of life, and serum 25(OH)D levels following vitamin D supplementation. The findings suggest that vitamin D alleviates neuropathic pain by modulating inflammatory responses, promoting nerve regeneration, and enhancing the expression of neurotrophic factors. Limitations: Further randomized controlled trials are needed to confirm the therapeutic efficacy of vitamin D supplementation and to establish the optimal dosage, frequency, and treatment duration associated with it. Conclusion: The findings support the consideration of vitamin D supplementation as a potential adjunctive strategy for managing painful DPN.