Role of Vitamin D as an Adjunctive Therapy in the Treatment of Type 2 Diabetes Mellitus: An Evidence-Based Review

The increasing global prevalence of type 2 diabetes mellitus (T2DM) requires comprehensive and multifactorial approaches to its management.Vitamin D has attracted interest due to its potential role in regulating insulin secretion and sensitivity.This study aimed to evaluate the effectiveness of vitamin D supplementation as an adjunct therapy for glycaemic control in individuals with T2DM.An evidence-based review was conducted through searches of the PubMed, Cochrane Library, ECRI Guidelines Trust®, and SciELO databases, including articles published between October 2015 and October 2025 in Portuguese, English, and Spanish.Of the 162 articles identified, 20 were selected based on their relevance to the predefined outcomes.The results suggest a trend towards improved glycaemic control with vitamin D supplementation.However, the heterogeneity among studies limits the consistency of the findings.Current evidence remains insufficient to recommend routine vitamin D supplementation for all individuals with T2DM.