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Current Nutrition & Food Science


ISSN (Print): 1573-4013
ISSN (Online): 2212-3881

Review Article

Intestinal Absorption and Factors Influencing Bioavailability of Magnesium- An Update

Author(s): Jan Philipp Schuchardt and Andreas Hahn*

Volume 13, Issue 4, 2017

Page: [260 - 278] Pages: 19

DOI: 10.2174/1573401313666170427162740

open access plus


Background: Information on the bioavailability of the essential mineral Mg2+ is sparse.

Objective/Method: Evaluation of the present knowledge on factors influencing the bioavailability and intestinal absorption of Mg2+.

Results: Mg2+ is absorbed via a paracellular passive and a transcellular active pathway that involves TRPM6/7 channel proteins. The bioavailability of Mg2+ varies within a broad range, depending on the dose, the food matrix, and enhancing and inhibiting factors. Dietary factors impairing Mg2+ uptake include high doses of other minerals, partly fermentable fibres (e.g., hemicellulose), non-fermentable fibres (e.g., cellulose, lignin), phytate and oxalate, whereas proteins, medium- chain-triglycerides, and low- or indigestible carbohydrates (e.g., resistant starch, oligosaccharides, inulin, mannitol and lactulose) enhance Mg2+ uptake. The Mg2+ dose is a major factor controlling the amount of Mg2+ absorbed. In principle, the relative Mg2+ uptake is higher when the mineral is ingested in multiple low doses throughout the day compared to a single, large intake of Mg2+. The type of Mg2+ salt appears less relevant than is often thought. Some studies demonstrated a slightly higher bioavailability of organic Mg2+ salts compared to inorganic compounds under standardized conditions, whereas other studies did not.

Conclusion: Due to the lack of standardized tests to assess Mg2+ status and intestinal absorption, it remains unclear which Mg2+ binding form produces the highest bioavailability. The Mg2+ intake dose combined with the endogenous Mg2+ status is more important. Because Mg2+ cannot be stored but only retained for current needs, a higher absorption is usually followed by a higher excretion of the mineral.

Keywords: Mg-absorption, bioavailability, intestinal uptake, meal composition, dietary fibre, oligosaccharides.

Graphical Abstract

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