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World J Diabetes. May 15, 2023; 14(5): 585-593
Published online May 15, 2023. doi: 10.4239/wjd.v14.i5.585
Association between metformin and vitamin B12 deficiency in patients with type 2 diabetes
Ehsan Sayedali, Ali Erdinç Yalin, Serap Yalin
Ehsan Sayedali, Ali Erdinç Yalin, Serap Yalin, Department of Biochemistry,Faculty of Pharmacy, Mersin University, Mersin 33169, Turkey
Author contributions: All authors contributed equally.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Serap Yalin, PhD, Professor, Department of Biochemistry, Faculty of Pharmacy, Mersin University, Yenisehir Campus, Mersin 33169, Turkey. syalin01@hotmail.com
Received: December 28, 2022
Peer-review started: December 28, 2022
First decision: January 9, 2023
Revised: January 20, 2023
Accepted: April 7, 2023
Article in press: April 7, 2023
Published online: May 15, 2023
Processing time: 137 Days and 18.4 Hours
Abstract

Diabetes mellitus (DM) is still one of the most common diseases worldwide, and its prevalence is still increasing globally. According to the American and European recommendations, metformin is considered a first-line oral hypo-glycemic drug for controlling type 2 DM (T2DM) patients. Metformin is the ninth most often prescribed drug in the world, and at least 120 million diabetic people are estimated to receive the drug. In the last 20 years, there has been increasing evidence of vitamin B12 deficiency among metformin-treated diabetic patients. Many studies have reported that vitamin B12 deficiency is related to the ma-labsorption of vitamin B12 among metformin-treated T2DM patients. Vitamin B12 deficiency may have a very bad complication for the T2DM patient. In this review, we will focus on the effect of metformin on the absorption of vitamin B12 and on its proposed mechanisms in hindering vitamin B12 absorption. In addition, the review will describe the clinical outcomes of vitamin B12 deficiency in metformin-treated T2DM.

Keywords: Metformin; Vitamin B 12 deficiency; Diabetes mellitus; Vitamin B12; Type 2 diabetes mellitus

Core Tip: In the last 20 years, there was increasing evidence of the presence of vitamin B12 deficiency among metformin-treated diabetic patients. Vitamin B12 deficiency may have a very bad complication for the T2DM patient. This review will focus on the effect of metformin on the absorption of vitamin B12 and on its proposed mechanisms in hindering vitamin B12 absorption. In addition to that, the review will describe the clinical outcomes of vitamin B12 deficiency in metformin-treated T2DM.