It is a truth sheet supposed for well being professionals. For a reader-friendly overview of Magnesium, see our shopper truth sheet on Magnesium.
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Introduction
Magnesium, an considerable mineral within the physique, is of course current in lots of meals, added to different meals merchandise, accessible as a dietary complement, and current in some medicines (equivalent to antacids and laxatives). Magnesium is a cofactor in additional than 300 enzyme programs that regulate numerous biochemical reactions within the physique, together with protein synthesis, muscle and nerve operate, blood glucose management, and blood strain regulation [1-3]. Magnesium is required for vitality manufacturing, oxidative phosphorylation, and glycolysis. It contributes to the structural improvement of bone and is required for the synthesis of DNA, RNA, and the antioxidant glutathione. Magnesium additionally performs a job within the energetic transport of calcium and potassium ions throughout cell membranes, a course of that’s essential to nerve impulse conduction, muscle contraction, and regular coronary heart rhythm [3].
An grownup physique accommodates roughly 25 g magnesium, with 50% to 60% current within the bones and a lot of the relaxation in tender tissues [4]. Lower than 1% of complete magnesium is in blood serum, and these ranges are stored underneath tight management. Regular serum magnesium concentrations vary between 0.75 and 0.95 millimoles (mmol)/L [1,5]. Hypomagnesemia is outlined as a serum magnesium stage lower than 0.75 mmol/L [6]. Magnesium homeostasis is basically managed by the kidney, which generally excretes about 120 mg magnesium into the urine every day [2]. Urinary excretion is diminished when magnesium standing is low [1].
Assessing magnesium standing is troublesome as a result of most magnesium is inside cells or in bone [3]. Essentially the most generally used and available technique for assessing magnesium standing is measurement of serum magnesium focus, regardless that serum ranges have little correlation with complete physique magnesium ranges or concentrations in particular tissues [6]. Different strategies for assessing magnesium standing embrace measuring magnesium concentrations in erythrocytes, saliva, and urine; measuring ionized magnesium concentrations in blood, plasma, or serum; and conducting a magnesium-loading (or “tolerance”) take a look at. No single technique is taken into account passable [7]. Some specialists [4] however not others [3] think about the tolerance take a look at (during which urinary magnesium is measured after parenteral infusion of a dose of magnesium) to be the most effective technique to evaluate magnesium standing in adults. To comprehensively consider magnesium standing, each laboratory checks and a medical evaluation is likely to be required [6].
Really useful Intakes
Consumption suggestions for magnesium and different vitamins are offered within the Dietary Reference Intakes (DRIs) developed by the Meals and Vitamin Board (FNB) on the Institute of Drugs of the Nationwide Academies (previously Nationwide Academy of Sciences) [1]. DRI is the overall time period for a set of reference values used to plan and assess nutrient intakes of wholesome folks. These values, which fluctuate by age and intercourse, embrace:
Desk 1 lists the present RDAs for magnesium [1]. For infants from beginning to 12 months, the FNB established an AI for magnesium that’s equal to the imply consumption of magnesium in wholesome, breastfed infants, with added strong meals for ages 7–12 months.
*Satisfactory Consumption (AI)
Sources of Magnesium – “magnesium daily dose”
Meals
Magnesium is broadly distributed in plant and animal meals and in drinks. Inexperienced leafy greens, equivalent to spinach, legumes, nuts, seeds, and entire grains, are good sources [1,3]. Usually, meals containing dietary fiber present magnesium. Magnesium can also be added to some breakfast cereals and different fortified meals. Some kinds of meals processing, equivalent to refining grains in ways in which take away the nutrient-rich germ and bran, decrease magnesium content material considerably [1]. Chosen meals sources of magnesium are listed in Desk 2.
Faucet, mineral, and bottled waters can be sources of magnesium, however the quantity of magnesium in water varies by supply and model (starting from 1 mg/L to greater than 120 mg/L) [8].
Roughly 30% to 40% of the dietary magnesium consumed is often absorbed by the physique [2,9].
*DV = Each day Worth. The U.S. Meals and Drug Administration (FDA) developed DVs to assist customers evaluate the nutrient contents of meals and dietary dietary supplements inside the context of a complete weight loss plan. The DV for magnesium is 420 mg for adults and kids aged 4 years and older [11]. FDA doesn’t require meals labels to checklist magnesium content material until magnesium has been added to the meals. Meals offering 20% or extra of the DV are thought of to be excessive sources of a nutrient, however meals offering decrease percentages of the DV additionally contribute to a healthful weight loss plan.
The U.S. Division of Agriculture’s (USDA’s) FoodData Central [10] lists the nutrient content material of many meals and offers complete checklist of meals containing magnesium organized by nutrient content material and by meals title.
Dietary dietary supplements
Magnesium dietary supplements can be found in a wide range of kinds, together with magnesium oxide, citrate, and chloride [2,3]. The Complement Info panel on a dietary complement label declares the quantity of elemental magnesium within the product, not the load of all the magnesium-containing compound.
Absorption of magnesium from totally different sorts of magnesium dietary supplements varies. Types of magnesium that dissolve nicely in liquid are extra utterly absorbed within the intestine than much less soluble kinds [2,12]. Small research have discovered that magnesium within the aspartate, citrate, lactate, and chloride kinds is absorbed extra utterly and is extra bioavailable than magnesium oxide and magnesium sulfate [12-16]. One research discovered that very excessive doses of zinc from dietary supplements (142 mg/day) can intrude with magnesium absorption and disrupt the magnesium stability within the physique [17].
Medicines
Magnesium is a major ingredient in some laxatives [18]. Phillips’ Milk of Magnesia®, for instance, offers 500 mg elemental magnesium (as magnesium hydroxide) per tablespoon; the instructions advise taking as much as 4 tablespoons/day for adolescents and adults [19]. (Though such a dose of magnesium is nicely above the secure higher stage, a few of the magnesium just isn’t absorbed due to the treatment’s laxative impact.) Magnesium can also be included in some cures for heartburn and upset abdomen attributable to acid indigestion [18]. Further-strength Rolaids®, for instance, offers 55 mg elemental magnesium (as magnesium hydroxide) per pill [20], though Tums® is magnesium free [21].
Magnesium Intakes and Standing
Dietary surveys of individuals in the USA constantly present that many individuals eat lower than beneficial quantities of magnesium. An evaluation of information from the Nationwide Well being and Vitamin Examination Survey (NHANES) of 2013-2016 discovered that 48% of People of all ages ingest much less magnesium from meals and drinks than their respective EARs; grownup males aged 71 years and older and adolescent women and men are most probably to have low intakes [22]. In a research utilizing knowledge from NHANES 2003–2006 to evaluate mineral intakes amongst adults, common intakes of magnesium from meals alone have been greater amongst customers of dietary dietary supplements (350 mg for males and 267 mg for girls, equal to or barely exceeding their respective EARs) than amongst nonusers (268 mg for males and 234 for girls) [23]. When dietary supplements have been included, common complete intakes of magnesium have been 449 mg for males and 387 mg for girls, nicely above EAR ranges.
No present knowledge on magnesium standing in the USA can be found. Figuring out dietary consumption of magnesium is the standard proxy for assessing magnesium standing. NHANES has not decided serum magnesium ranges in its members since 1974 [24], and magnesium just isn’t evaluated in routine electrolyte testing in hospitals and clinics [2].
Magnesium Deficiency
Symptomatic magnesium deficiency attributable to low dietary consumption in otherwise-healthy folks is rare as a result of the kidneys restrict urinary excretion of this mineral [3]. Nonetheless, habitually low intakes or extreme losses of magnesium attributable to sure well being circumstances, persistent alcoholism, and/or the usage of sure medicines can result in magnesium deficiency.
Early indicators of magnesium deficiency embrace lack of urge for food, nausea, vomiting, fatigue, and weak spot. As magnesium deficiency worsens, numbness, tingling, muscle contractions and cramps, seizures, persona modifications, irregular coronary heart rhythms, and coronary spasms can happen [1,2]. Extreme magnesium deficiency may end up in hypocalcemia or hypokalemia (low serum calcium or potassium ranges, respectively) as a result of mineral homeostasis is disrupted [2].