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

Abstract

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. This systematic review aims to investigate whether vitamin D supplementation improves neuropathic symptoms in patients with painful DPN. A narrative review. 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. 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. 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. The findings support the consideration of vitamin D supplementation as a potential adjunctive strategy for managing painful DPN.