Kappeler D¹

¹ Inamed GmbH, 82131 Gauting

Background: A number of studies have tried to investigate which Mg compounds are best suited for Mg supplementation. Results suggest that organic Mg compounds might be superior to the inorganic Mg compounds in terms of bioavailability, but a reliable statement cannot yet be made due to methodological differences in the applied study designs.
Methods: This single-center, randomized, 2-period, 2-supplementation, 2-sequence, single-dose, cross-over study was conducted in 20 healthy male to investigate and compare the bioavailability of Mg citrate and Mg oxide. Subjects were supplemented with magnesium to saturate their Mg-pools before administration of each study product. The bioavailability of both Mg compounds was then assessed by measurement of the renally eliminated Mg quantity during an interval of 24 hours after single-dose Mg administration (A_{e 0-24h}). Additionally, the Mg concentrations in a subset of leukocytes, in erythrocytes and in serum were measured on an exploratory basis.
Results: A_{e 0-24h} of magnesium was higher for Mg citrate than for Mg oxide. A_{e 0-24h} for both study products was
compared by analysis of variance (ANOVA), revealing an adjusted mean difference of, which was statistically significant (95% confidence interval of 0.212 to 0.918 mmol, p = 0.0034). Besides, serum Mg concentrations were statistically significantly higher for Mg citrate than for Mg oxide at several time points after administration. No statistically significant difference was shown in intracellular Mg contents.
Conclusions: This study indicates a higher bioavailability of Mg citrate compared to Mg oxide. It can be concluded that Mg citrate, similar to other organic Mg compounds, may be more suitable than Mg oxide for the purpose of oral Mg supplementation.