Magnesium and Space Flight

Abstract

Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 43 astronauts (34 male, 9 female; 47 ± 5 years old, mean ± SD) before, during, and after 4–6-month space missions. We also studied individuals participating in a ground analog of space flight (head-down-tilt bed rest; n = 27 (17 male, 10 female), 35 ± 7 years old). We evaluated serum concentration and 24-h urinary excretion of magnesium, along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-day space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4–6-month space missions.

Collection of Biospecimens from the Inspiration4 Mission Establishes the Standards for the Space Omics and Medical Atlas (SOMA)

“…A wide variety of assays can be performed on urine samples. Previous studies have included viral reactivation 40,44,46 , urinary cortisol 47,55 , iron and magnesium measurements 49,52 , bone 50,51,53,56 , kidney stones 50,51 , proteomics 11 , telomere measurements 59 , and various biomarkers and metabolites 17,55 .…”

Collection of Biospecimens from the Inspiration4 Mission Establishes the Standards for the Space Omics and Medical Atlas (SOMA)

“…A wide variety of assays can be performed on urine samples. Previous studies have included viral reactivation 40,44,46 , urinary cortisol 47,55 , iron and magnesium measurements 49,52 , bone status 50,51,53,56 , kidney stones 50,51 , proteomics 11 , telomere measurements 59 , and various biomarkers and metabolites 17,55 .…”

Physiological Adaptations to Life in Space: An Update

“…The renal system participates in the homeostasis of magnesium, an essential nutrient for bone, cardiovascular and muscle health. Space flight increases the concentration of magnesium in the urine and blood, but it remains the same in the tissues, demonstrating an adapted protective homeostatic response, with no need for magnesium replacement during trips of four to six months (Smith and Zwart 2015). The main acute adaptations of the renal and hydroelectrolytic system are summarized below (Krittanawong et al 2023;Russomano and Castro 2020;Stella et al 2021).…”