Interpreting magnesium status to enhance clinical care

Abstract

Purpose of review To update advances in identifying factors affecting magnesium (Mg) status that assist in providing improved evidence-based clinical decision-making for assessing Mg status. Recent findings Findings from recent cohort studies, small randomized control trials, and multiple meta-analyses reinforce earlier work that serum Mg concentrations, urinary Mg excretion, and Mg dietary intakes are inversely associated with cardiovascular disease, chronic kidney disease, and diabetes. These studies indicate that the reference range for serum Mg needs updating, and that individuals with serum Mg in the range of 0.75–0.85 mmol/L and displaying changes in other factors associated with a low Mg status may be Mg deficient. Individuals with serum Mg concentrations below this range most likely are Mg deficient, and above this range, are most likely Mg sufficient. Summary The combined determination of serum Mg concentration, 24-hr urinary Mg excretion, and dietary Mg intake is currently the most practical method to obtain a sound assessment of Mg status. The strong correlations of Mg deficiency with increased risk of several chronic diseases, some of which exist as co-morbidities, indicate that Mg status should be ascertained in subjects presenting such pathology.

Circulating Ionized Magnesium: Comparisons with Circulating Total Magnesium and the Response to Magnesium Supplementation in a Randomized Controlled Trial

“…A value of 0 indicates that the iMg measured in refrigerated (or frozen) and fresh were identical. 3 Refrigerated and frozen blood samples were measured in serum, while fresh was measured in whole blood.…”

“…The majority of total body Mg resides within the bone tissue, while less than 1% of total body Mg lies extra-cellularly. Serum total Mg (tMg) has traditionally been used to assess Mg status in both clinical and research settings, with a reference range of 0.75-0.95 mmol/L (multiply mmol/L by 2.43 for mg/dL; 1.82-2.31 mg/dL) [3]. There are important considerations to be cognizant of when using tMg to reflect Mg status.…”

“…iMg is infrequently measured in research or clinical settings [3,4], likely because it requires an immediate analysis of whole blood iMg, specialized equipment is required for measurement, and iMg measurement can be prone to interference by individual-level factors, such as pH and serum calcium. While tMg and iMg generally correlate in normal, healthy subjects, the literature has been mixed in both observational studies and randomized controlled trials (RCTs) of Mg supplementation [7][8][9][10].…”

“…Mean (standard deviation); 2 the distribution (in percentiles) of the difference between refrigerated vs. fresh and frozen vs. fresh. A value of 0 indicates that the iMg measured in refrigerated (or frozen) and fresh were identical 3. Refrigerated and frozen blood samples were measured in serum, while fresh was measured in whole blood.…”

Impact of rising body weight and cereal grain food processing on human magnesium nutrition

“…measures of total Mg intake minus excretion. Since Kumssa et al (2015) publication, research has found that homeostasis of Mg in human physiology not only includes control of absorption in the gastrointestinal tract and excretion via kidney but also translocation of Mg from bone and other storage areas to maintain blood levels during times of low Mg intakes, with replacement of those storage sites when Mg intakes again become high (de Baaij et al 2015;Costello and Nielsen 2017). Thus, chronically suboptimal Mg intakes can result in a growing depletion of body Mg stores termed Chronic Latent Magnesium Deficit (CLMD) (Elin 2010;Rosanoff et al 2012;Blaine et al 2015) which can manifest in spite of measures of normal serum Mg and neutral Mg balance.…”