Magnesium metabolism in health and disease

ArticleinInternational Urology and Nephrology 41(2):357-62 · April 2009with17 Reads
DOI: 10.1007/s11255-009-9548-7 · Source: PubMed
Abstract
Magnesium (Mg) is the main intracellular divalent cation, and under basal conditions the small intestine absorbs 30-50% of its intake. Normal serum Mg ranges between 1.7-2.3 mg/dl (0.75-0.95 mmol/l), at any age. Even though eighty percent of serum Mg is filtered at the glomerulus, only 3% of it is finally excreted in the urine. Altered magnesium balance can be found in diabetes mellitus, chronic renal failure, nephrolithiasis, osteoporosis, aplastic osteopathy, and heart and vascular disease. Three physiopathologic mechanisms can induce Mg deficiency: reduced intestinal absorption, increased urinary losses, or intracellular shift of this cation. Intravenous or oral Mg repletion is the main treatment, and potassium-sparing diuretics may also induce renal Mg saving. Because the kidney has a very large capacity for Mg excretion, hypermagnesemia usually occurs in the setting of renal insufficiency and excessive Mg intake. Body excretion of Mg can be enhanced by use of saline diuresis, furosemide, or dialysis depending on the clinical situation.
    • "The kidney has a very large capacity for Mg excretion and when the renal threshold is exceeded, most of the excess filtered Mg is excreted into the urine [48]. Under basal conditions the small intestine absorbs 30%–50% of Mg intake, but this percentage diminishes with increasing amount of Mg intake [48]. In general Mg is at risk for being deficient in the diet [49]. "
    [Show abstract] [Hide abstract] ABSTRACT: This study investigates differences and associations between urinary mineral concentrations and calcaneal bone measures assessed by quantitative ultrasonography (QUS) in 4322 children (3.1-11.9 years, 50.6% boys) from seven European countries. Urinary mineral concentrations and calcaneal QUS parameters differed significantly across countries. Clustering revealed a lower stiffness index (SI) in children with low and medium urinary mineral concentrations, and a higher SI in children with high urinary mineral concentrations. Urinary sodium (uNa) was positively correlated with urinary calcium (uCa), and was positively associated with broadband ultrasound attenuation and SI after adjustment for age, sex and fat-free mass. Urinary potassium (uK) was negatively correlated with uCa but positively associated with speed of sound after adjustment. No association was found between uCa and QUS parameters after adjustment, but when additionally adjusting for uNa, uCa was negatively associated with SI. Our findings suggest that urinary mineral concentrations are associated with calcaneal QUS parameters and may therefore implicate bone properties. These findings should be confirmed in longitudinal studies that include the food intake and repeated measurement of urinary mineral concentrations to better estimate usual intake and minimize bias.
    Full-text · Article · May 2016
    • "Considering human health, magnesium plays a role in the structural development of bones, and the active transport of calcium and potassium ions across cell membranes, which is important to nerve impulse conduction , muscle contraction, and a normal heart rhythm. Moreover, too much magnesium from food does not pose a health risk for healthy individuals (Musso, 2009). Table 5shows that aluminium was detected only in fruits harvested from plants irrigated with outflow waters from Filters 1, 2 and 6. "
    [Show abstract] [Hide abstract] ABSTRACT: Due to water scarcity in many arid countries, there is considerable interest in recycling wastewater streams such as treated urban wastewater for irrigation in the agricultural sector. The aim of this study is to assess the contamination of soil and Capsicum annuum (grown in pots) irrigated by domestic wastewaters treated by different wetland types between September 2013 and September 2014. The objectives were to assess (a) the suitability of the irrigation water for growth when using recycled wastewater contaminated by trace minerals and pathogens, (b) the impact of differently treated wastewaters on soil and fruits as a function of the wetland type, and (c) the marketable yield of the harvest as a function of mineral and biological contamination risk. Ortho-phosphate-phosphorus, ammonia–nitrogen, potassium and manganese concentrations in the irrigation water considerably exceeded the thresholds. High contamination levels by total coliforms, Salmonella spp. and Streptococcus spp. were detected. No mineral contamination was observed in the soils due to irrigation with treated wastewater. Results showed that slight to moderate zinc contamination was detected in some vegetables. Potassium accumulation in the yield showed the highest values followed by zinc. In contrast, the lowest mineral accumulation of the yield was observed for iron. No bacterial contamination was detected for fruits harvested from plants irrigated by wetland outflow water. In contrast, fruits harvested from those plants irrigated by preliminary treated wastewater showed high contamination by total coliforms, Streptococcus spp. and Salmonella spp. especially for fruits, which were located close to the contaminated soil surface. However, findings indicate that vegetables receiving wastewater treated with wetlands can be considered as safe compared to those receiving only preliminary treated wastewater. High yields in terms of economic return were associated with tap water and an organic growth medium, and a wetland with a small aggregate size and a low contact time.
    Full-text · Article · Mar 2016
    • "It is of critical importance for various metabolic reactions, including energy production , protein and nucleic acid synthesis, cell cycle regulation and ion metabolism [2] . Mg 2+ is closely related to many important human diseases such as type 2 diabetes mellitus, hypertension and cardiovascular diseases345. Despite the great importance of this cation, our understanding of how cells regulate the transportation and homeostasis of Mg 2+ remains quite preliminary. "
    [Show abstract] [Hide abstract] ABSTRACT: The homeostasis of magnesium (Mg(2+)), an abundant divalent cation indispensable for many biological processes including mitochondrial functions, is underexplored. In yeast, the mitochondrial Mg(2+) homeostasis is accurately controlled through the combined effects of importers, Mrs2 and Lpe10, and an exporter, Mme1. However, little is known about this Mg(2+) homeostatic process in multicellular organisms. Here, we identified the first mitochondrial Mg(2+) transporter in Drosophila, the orthologue of yeast Mme1, dMme1, by homologous comparison and functional complementation. dMme1 can mediate the exportation of mitochondrial Mg(2+) when heterologously expressed in yeast. Altering the expression of dMme1, although only resulting in about a 10% change in mitochondrial Mg(2+) levels in either direction, led to a significant survival reduction in Drosophila. Furthermore, the reduced survival resulting from dMme1 expression changes could be completely rescued by feeding the dMME1-RNAi flies Mg(2+)-restricted food or the dMME1-over-expressing flies the Mg(2+)-supplemented diet. Our studies therefore identified the first Drosophila mitochondrial Mg(2+) exporter, which is involved in the precise control of mitochondrial Mg(2+) homeostasis to ensure an optimal state for survival.
    Full-text · Article · Oct 2015
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