Magnesium Bioavailability and Tolerability Do Not Differ between Two Supplements with Different Release Properties

Abstract

Magnesium (Mg²⁺) is one of the most frequently supplemented micronutrients. Due to possible gastrointestinal side effects, the European Food Safety Authority and the Institute of Medicine set the upper intake level for Mg²⁺ from supplements to 250 and 350 mg, respectively. Nevertheless, systematic data concerning the tolerability of Mg²⁺ supplements are scarce. The aim of the study was to directly compare the bioavailability and tolerability of two 500 mg Mg²⁺ supplements in a crossover study with duplicate determination. The different release properties were either a direct release (one phase) or a delayed release of the second half (two phases). An open-label, controlled trial with a crossover design, duplicate determination, and one-week washout phases was conducted. The participants ingested the test product after overnight fasting. Blood samples were taken at baseline and after 1, 2, 3, 4, 6, and 8 hours, and urine was collected over a period of 24 hours. The participants were on standardized nutrition during all examination days. There were no significant differences between the test products regarding 24-hour renal Mg²⁺ excretion and area under the curve of serum Mg²⁺ levels for 8 hours. Both test products were well tolerated with a very low frequency of gastrointestinal adverse effects and no significant differences between the test products. The Mg²⁺ bioavailability did not differ between the test products. The supplements examined had the same good tolerability. Both test products are therefore suited to enhance Mg²⁺ supply without relevant side effects.

Keywords:

• bioavailability
• general nutrition
• magnesium
• supplement
• tolerability

Acknowledgments

The authors thank the participants who took part in this study.

Declaration of interest

The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Funding

This study was in part funded by Merz Consumer Care (Frankfurt a. M., Germany). Study realization, data analysis, and reporting were undertaken independently from the sponsor.

Additional information

Notes on contributors

Theresa Greupner

Theresa Greupner, PhD, Institute of Food Science and Human Nutrition, Leibniz University Hannover, Hannover, Germany. Research interests: bioavailability of calcium/magnesium, omega-3 fatty acids, oxylipins.

Inga Schneider

Inga Schneider, PhD, Institute of Food Science and Human Nutrition, Leibniz University Hannover, Hannover, Germany. Research interests: bioavailability of nutrients, mineral water, glycemic response

Sandra Gellert

Sandra Gellert, PhD, Institute of Food Science and Human Nutrition, Leibniz University Hannover, Hannover, Germany. Research interests: nutrition assessment, clinical investigation, vitamin D.

Andreas Hahn

Andreas Hahn, PhD, Institute of Food Science and Human Nutrition, Leibniz University Hannover, Hannover, Germany. Research interests: nutrition and prevention, bioavailability of nutrients, omega-3-fatty acids.