{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T00:08:25Z","timestamp":1789517305139,"version":"build-2803163510"},"reference-count":53,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,8,7]],"date-time":"2025-08-07T00:00:00Z","timestamp":1754524800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Clinics and Practice"],"abstract":"<jats:p>Vitamin D has emerged as a modulatory factor in the pathogenesis and management of diabetes mellitus due to its influence on pancreatic \u03b2-cell function, immune regulation, and inflammatory pathways. This narrative review critically examines mechanistic and clinical evidence linking vitamin D status with type 1 diabetes (T1DM), type 2 diabetes (T2DM), and gestational diabetes (GDM). In T1DM, vitamin D\u2019s immunomodulatory effects are thought to protect \u03b2-cells from autoimmune destruction; epidemiological studies associate vitamin D sufficiency with lower T1DM incidence and improved glycemic control, although causality remains under investigation. In T2DM, vitamin D deficiency is associated with worsened metabolic control and may contribute to disease development in at-risk individuals; however, it does not influence the initial onset of T2DM in patients who are already diagnosed. Intervention trials indicate that correcting the deficiency can modestly improve insulin sensitivity, \u03b2-cell function, and metabolic parameters. GDM has similarly been linked to hypovitaminosis D, with low maternal vitamin D levels associated with higher GDM risk and adverse perinatal outcomes; mechanistic insights suggest that adequate vitamin D supports glucose homeostasis in pregnancy, and emerging trials demonstrate improved insulin resistance with maternal vitamin D supplementation. Across these diabetes subtypes, maintaining sufficient vitamin D levels appears to confer metabolic benefits and may serve as an adjunct to current preventive and therapeutic strategies. However, definitive evidence from large-scale trials is required to establish optimal vitamin D supplementation protocols and confirm its efficacy in diabetes care.<\/jats:p>","DOI":"10.3390\/clinpract15080148","type":"journal-article","created":{"date-parts":[[2025,8,7]],"date-time":"2025-08-07T09:25:52Z","timestamp":1754558752000},"page":"148","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["The Role of Vitamin D Supplementation in Type 1, Type 2, and Gestational Diabetes: A Comprehensive Updated Narrative Review"],"prefix":"10.3390","volume":"15","author":[{"given":"Asala","family":"Nasser","sequence":"first","affiliation":[{"name":"Department of Clinical Nutrition, College of Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4923-484X","authenticated-orcid":false,"given":"Dimitrios","family":"Papandreou","sequence":"additional","affiliation":[{"name":"Department of Clinical Nutrition, College of Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sousana K.","family":"Papadopoulou","sequence":"additional","affiliation":[{"name":"Department of Nutritional Sciences and Dietetics, School of Health Sciences, International Hellenic University, 57400 Thessaloniki, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3048-7481","authenticated-orcid":false,"given":"Leila","family":"Cheikh Ismail","sequence":"additional","affiliation":[{"name":"Department of Clinical Nutrition, College of Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1056\/NEJMra070553","article-title":"Vitamin D deficiency","volume":"357","author":"Holick","year":"2007","journal-title":"N. 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