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World J Gastroenterol. Jan 14, 2023; 29(2): 332-342
Published online Jan 14, 2023. doi: 10.3748/wjg.v29.i2.332
Current opinion on the regulation of small intestinal magnesium absorption
Siriporn Chamniansawat, Nasisorn Suksridechacin, Narongrit Thongon
Siriporn Chamniansawat, Division of Anatomy, Department of Medical Sciences, Faculty of Allied Health Sciences, Burapha University, Muang 20131, Chonburi, Thailand
Nasisorn Suksridechacin, Biodiversity Research Centre, Thailand Institute of Scientific and Technological Research, Khlong Luang 12120, Pathum Thani, Thailand
Narongrit Thongon, Division of Physiology, Department of Medical Sciences, Faculty of Allied Health Sciences, Burapha University, Muang 20131, Chonburi, Thailand
Author contributions: Chamniansawat S wrote the manuscript; Suksridechacin N wrote the manuscript; Thongon N wrote and edited the manuscript.
Conflict-of-interest statement: All 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: Narongrit Thongon, PhD, Associate Professor, Division of Physiology, Department of Medical Sciences, Faculty of Allied Health Sciences, Burapha University, 169 Long-Hard Bangsaen Road, Saensook, Muang 20131, Chonburi, Thailand. narongritt@buu.ac.th
Received: August 10, 2022
Peer-review started: August 10, 2022
First decision: October 20, 2022
Revised: October 25, 2022
Accepted: November 18, 2022
Article in press: November 18, 2022
Published online: January 14, 2023
Abstract

Magnesium (Mg2+) has an important role in numerous biological functions, and Mg2+ deficiency is associated with several diseases. Therefore, adequate intestinal absorption of Mg2+ is vital for health. The small intestine was previously thought to absorb digested Mg2+ exclusively through an unregulated paracellular mechanism, which is responsible for approximately 90% of total Mg2+ absorption. Recent studies, however, have revealed that the duodenum, jejunum, and ileum absorb Mg2+ through both transcellular and paracellular routes. Several regulatory factors of small intestinal Mg2+ uptake also have been explored, e.g., parathyroid hormone, fibroblast growth factor-23, apical acidity, proton pump inhibitor, and pH-sensing channel and receptors. The mechanistic factors underlying proton pump inhibitor suppression of small intestinal Mg2+, such as magnesiotropic protein dysfunction, higher mucosal bicarbonate secretion, Paneth cell dysfunction, and intestinal inflammation, are currently being explored. The potential role of small intestinal microbiomes in Mg2+ absorption has also been proposed. In this article, we reviewed the current knowledge on the mechanisms and regulatory factors of small intestinal Mg2+ absorption.

Keywords: Hormone, Magnesium absorption, Paneth cells, Proton pump inhibitor, Regulation, Small intestine

Core Tip: Small intestinal epithelium absorbs digested magnesium (Mg2+) through both transcellular active and paracellular passive mechanisms. Several regulatory factors of small intestinal Mg2+ uptake have been reported. Parathyroid hormone and fibroblast growth factor-23 directly inhibit transcellular Mg2+ absorption in the duodenum, jejunum, and ileum. The apical proton triggers acid-sensing ion-channel 1a and purinergic P2Y2 receptor activities, which stimulates mucosal bicarbonate secretion and induces MgCO3 precipitation to suppress absorption. Omeprazole suppresses Mg2+ absorption in the duodenum, jejunum, and ileum.