Article

Magnesium metabolism in health and disease.

Nephrology Department, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.
International Urology and Nephrology (Impact Factor: 1.29). 04/2009; 41(2):357-62. 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.

0 Bookmarks
 · 
66 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present study evaluated the influence of magnesium on insulin resistance in obese women. A case-control study involving 114 women on the age between 20 and 50 years old, divided into two groups: control (eutrophic women, n = 59) and case (obese women, n = 55). The analysis of magnesium intake was carried out through the 3-day food record and also NutWin software version 1.5. The plasma, erythrocyte, and urinary magnesium concentrations were determined by flame atomic absorption spectrophotometry. The determinations of serum glucose and serum insulin were performed by enzymatic colorimetric method and chemiluminescence, respectively. The insulin resistance was assessed by homeostasis model assessment insulin resistance (HOMA-IR). The mean values of magnesium intake were lower than those recommended, without difference between groups (p > 0.05). All the patients who were evaluated showed adequate mean concentrations of magnesium in the plasma and erythrocyte. The urinary excretion of this mineral was lower than the reference values in both groups and did not show significant difference (p > 0.05). The values of serum glucose, serum insulin, and HOMA-IR were higher in obese women compared to the control group. A negative correlation was observed between erythrocyte magnesium and glycemic parameters (p < 0.05). Obese patients take in foods with low dietary magnesium content, and they show hypomagnesuria as a compensatory mechanism to keep the plasma concentration of this mineral in adequate levels. The correlation between the erythrocyte magnesium concentration and the parameters of glycemic control suggests the influence of this mineral on the index of insulin resistance in obese women.
    Biological Trace Element Research 07/2014; · 1.61 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Understanding the nutritional demands on serving military personnel is critical to inform training schedules and dietary provision. Troops deployed to Afghanistan face austere living and working environments. Observations from the military and those reported in the British and US media indicated possible physical degradation of personnel deployed to Afghanistan. Therefore, the present study aimed to investigate the changes in body composition and nutritional status of military personnel deployed to Afghanistan and how these were related to physical fitness. In a cohort of British Royal Marines (n 249) deployed to Afghanistan for 6 months, body size and body composition were estimated from body mass, height, girth and skinfold measurements. Energy intake (EI) was estimated from food diaries and energy expenditure measured using the doubly labelled water method in a representative subgroup. Strength and aerobic fitness were assessed. The mean body mass of volunteers decreased over the first half of the deployment ( - 4·6 (sd 3·7) %), predominately reflecting fat loss. Body mass partially recovered (mean +2·2 (sd 2·9) %) between the mid- and post-deployment periods (P< 0·05). Daily EI (mean 10 590 (sd 3339) kJ) was significantly lower than the estimated daily energy expenditure (mean 15 167 (sd 1883) kJ) measured in a subgroup of volunteers. However, despite the body mass loss, aerobic fitness and strength were well maintained. Nutritional provision for British military personnel in Afghanistan appeared sufficient to maintain physical capability and micronutrient status, but providing appropriate nutrition in harsh operational environments must remain a priority.
    British Journal Of Nutrition 07/2014; · 3.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective. To determine the prevalence of dysmagnesaemia among patients admitted to a trauma intensive care unit (ICU) and to investigate whether dysmagnesaemia at admission correlated with a worse outcome. Methods. In this retrospective case study of patients admitted to a regional level 1 trauma unit, from April 2007 to November 2010, de-identified patient data were obtained from the local patient database. Patients were divided into three groups (hypomagnesaemic, normomagnesaemic and hypermagnesaemic), which in turn were divided into two subgroups (blunt and penetrating trauma). The mortality between normo-and hypomagnesaemic patients, as well as between the subgroups, was analysed using χ 2 tests. The University of KwaZulu-Natal Biomedical Research Ethics Committee approved the study (BE207/09). Results. Of the 759 trauma patients studied, 10.7% were hypomagnesaemic and 1.3% were hypermagnesaemic at admission. No statistically significant difference in mortality was observed between the hypo-and normo-/hypermagnesaemic patients. Conclusion. Dysmagnesaemia is common among trauma patients admitted to the ICU, but is not necessarily correlated with a poorer outcome. S Afr J Crit Care 2014;30(2):45-50. DOI:10.7196/SAJCC.190 Magnesium (Mg) is a common mineral salt in the human body, being the second most prevalent intracellular cation, the majority of which is concentrated in bone, muscle and soft tissue. It is essential for over 300 enzymatic reactions and is a prerequisite for human life. [1-4] The main absorption of Mg occurs in the jejunum and ileum, while the kidneys have an important homeostatic role. [5]
    Southern African Journal of Critical Care 11/2014; 30(2):45-50.