SYSTEMATIC REVIEW article
Front. Nutr.
Sec. Nutrition and Metabolism
Volume 12 - 2025 | doi: 10.3389/fnut.2025.1663019
This article is part of the Research TopicBridging knowledge to action in vitamin D supplementationView all 6 articles
Dose-Response Effects of Vitamin D Supplementation on Vitamin D Status, Glycosylated Hemoglobin and Total Cholesterol in Patients with Diabetes Mellitus: A Systematic Review and Meta-Analysis
Provisionally accepted
- Department of Pharmacy, Shaanxi Provincial People's Hospital, Xi’an, China
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The impact of vitamin D levels on glycemic control and lipid metabolism in diabetic patients has received widespread attention. However, currently, there was no unified standard for vitamin D supplementation dosages, with significant variations among guideline recommendations. For instance, the 2022 ESPEN Guidelines recommended a daily supplementation of 1500-5,000 IU for patients at risk of vitamin D deficiency or who repeatedly experience vitamin D deficiency; however, guidelines from Italy suggested a daily supplement dose of 800-1000 IU for patients with vitamin D deficiency. In this study, we searched the PubMed, Web of Science, Embase, Cochrane Library, CBM, CNKI, and Wanfang databases from their inception to May 31, 2024 for literature. The effects of different supplementation levels on vitamin D levels, glycosylated hemoglobin levels and total cholesterol (TC) levels were analyzed using random-effects and fixed-effects models, respectively and we applied the Modified Jadad Scale and the Newcastle-Ottawa Scale (NOS) score to evaluate the quality of the RCT studies and retrospective analyses, respectively. We included a total of 7 papers involving 468 patients with a follow-up period of 3 to 6 months. The results of the study showed that vitamin D levels were significantly higher in the high-dose group than in the low-dose group at both 3 and 6 months of treatment (mean difference{MD} = -12.48, [95% confidence interval {CI}: -15.25 to -9.72 and MD = - 28.22, 95% CI [-40.92, -15.72], both P< 0.05), and the effect of prolonged treatment was more significant. glycosylated hemoglobin (HbA1c) levels were significantly lower in the high-dose group than in the low-dose group (MD = 0.41, 95% CI [0.14, 0.67], P=0.003), and TC levels were not significantly different between the two groups (MD = 1.84, 95% CI [-8.07, 0.67], P=0.72). Therefore, in patients with diabetes mellitus complicated by vitamin D deficiency, higher-dose supplementation (>4000 International Units/day) might have had potential advantages in increasing vitamin D levels and improving glycemic control. However, further studies were still needed to clarify the long-term safety and risk-benefit ratio of higher-dose supplementation.
Keywords: Diabetes Mellitus, Vitamin D levels, dose-response, Glycosylated hemoglobin, Total cholesterol, Vitamin D supplementation
Received: 10 Jul 2025; Accepted: 20 Oct 2025.
Copyright: © 2025 Cao, Zhou, Zhang, Zhang and Zhao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Ying Zhao, zhaoyingsrm@163.com
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