Magnesium deficiency is an
electrolyte disturbance
Electrolyte imbalance, or water-electrolyte imbalance, is an abnormality in the concentration of electrolytes in the body. Electrolytes play a vital role in maintaining homeostasis in the body. They help to regulate heart and neurological function ...
in which there is a low level of
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
in the body. It can result in multiple symptoms. Symptoms include
tremor, poor coordination, muscle spasms, loss of appetite, personality changes, and
nystagmus
Nystagmus is a condition of involuntary (or voluntary, in some cases) eye movement. Infants can be born with it but more commonly acquire it in infancy or later in life. In many cases it may result in reduced or limited vision. Due to the invol ...
.
[ Complications may include ]seizures
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with l ...
or cardiac arrest
Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and poss ...
such as from torsade de pointes
''Torsades de pointes, torsade de pointes'' or ''torsades des pointes'' (TdP) (, , translated as "twisting of peaks") is a specific type of abnormal heart rhythm that can lead to sudden cardiac death. It is a polymorphic ventricular tachycardia t ...
.[ Those with low magnesium often have ]low potassium
Hypokalemia is a low level of potassium (K+) in the blood serum. Mild low potassium does not typically cause symptoms. Symptoms may include feeling tired, leg cramps, weakness, and constipation. Low potassium also increases the risk of an abno ...
.[
Causes include low dietary intake, ]alcoholism
Alcoholism is, broadly, any drinking of alcohol that results in significant mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognized diagnostic entity. Predomi ...
, diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...
, increased urinary loss, poor absorption from the intestines, and diabetes mellitus
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
. A number of medications may also cause low magnesium, including proton pump inhibitors
Proton-pump inhibitors (PPIs) are a class of medications that cause a profound and prolonged reduction of stomach acid production. They do so by irreversibly inhibiting the stomach's H+/K+ ATPase proton pump.
They are the most potent inhibitor ...
(PPIs) and furosemide
Furosemide is a loop diuretic medication used to treat fluid build-up due to heart failure, liver scarring, or kidney disease. It may also be used for the treatment of high blood pressure. It can be taken by injection into a vein or by m ...
.[ The diagnosis is typically based on finding low blood magnesium levels (hypomagnesemia).] Normal magnesium levels are between 0.6 and 1.1 mmol/L (1.46–2.68 mg/dL) with levels less than 0.6 mmol/L (1.46 mg/dL) defining hypomagnesemia.[ Specific electrocardiogram (ECG) changes may be seen.][
Treatment is with magnesium either by mouth or intravenously.][ For those with severe symptoms, intravenous ]magnesium sulfate
Magnesium sulfate or magnesium sulphate (in English-speaking countries other than the US) is a chemical compound, a salt with the formula , consisting of magnesium cations (20.19% by mass) and sulfate anions . It is a white crystalline solid, ...
may be used.[ Associated low potassium or ]low calcium
Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mmo ...
should also be treated.[ The condition is relatively common among people in hospitals.]
Signs and symptoms
Deficiency of magnesium can cause tiredness, generalized weakness, muscle cramps
A cramp is a sudden, involuntary, painful skeletal muscle contraction or overshortening associated with electrical activity; while generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the ...
, abnormal heart rhythms, increased irritability of the nervous system
In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...
with tremors, paresthesias, palpitations, low potassium levels in the blood, hypoparathyroidism
Hypoparathyroidism is decreased function of the parathyroid glands with underproduction of parathyroid hormone (PTH). This can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany (involuntary m ...
which might result in low calcium levels in the blood, chondrocalcinosis
Chondrocalcinosis or cartilage calcification is calcification (accumulation of calcium salts) in hyaline cartilage and/or fibrocartilage.Rothschild, Bruce M It can be seen on radiography.
Causes
Buildup of calcium phosphate in the ankle joints h ...
, spasticity
Spasticity () is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia. It is also colloquially referred to as an unusual "tightness", stiffness, or "pull" of muscles ...
and tetany
Tetany or tetanic seizure is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disorders that increase the action potential frequency of muscle cells or the nerves that innervate them.
Muscle cramps caus ...
, migraines, epileptic seizure
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with los ...
s, basal ganglia calcifications and in extreme and prolonged cases coma, intellectual disability
Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation, Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by signif ...
or death. Magnesium plays an important role in carbohydrate metabolism and its deficiency may worsen insulin resistance, a condition that often precedes diabetes, or may be a consequence of insulin resistance.
People being treated on an intensive care unit
220px, Intensive care unit
An intensive care unit (ICU), also known as an intensive therapy unit or intensive treatment unit (ITU) or critical care unit (CCU), is a special department of a hospital or health care facility that provides intensi ...
(ICU) who have a low magnesium level may have a higher risk of requiring mechanical ventilation
Mechanical ventilation, assisted ventilation or intermittent mandatory ventilation (IMV), is the medical term for using a machine called a ventilator to fully or partially provide artificial ventilation. Mechanical ventilation helps move a ...
, and death.
Causes
Magnesium deficiency may result from gastrointestinal or kidney causes. Gastrointestinal causes include low dietary intake of magnesium, reduced gastrointestinal absorption or increased gastrointestinal loss due to rapid gastrointestinal transits. Kidney causes involve increased excretion of magnesium. Poor dietary intake of magnesium has become an increasingly important factor – many people consume diets high in refined foods such as white bread and polished rice which have been stripped of magnesium-rich plant fiber.
Magnesium deficiency is not uncommon in hospitalized patients. Up to 12% of all people admitted to hospital, and as high as 60–65% of people in an intensive care unit, have hypomagnesemia.
About 57% of the US population does not meet the US RDA for dietary intake of magnesium. The kidneys are very efficient at maintaining body levels; however, if the diet is deficient, or certain medications such as diuretics or proton pump inhibitors are used, or in chronic alcoholism,[ levels may drop.
Low levels of magnesium in blood may be due to not enough magnesium in the diet, the intestines not absorbing enough magnesium, or the kidneys excreting too much magnesium. Deficiencies may be due to the following conditions:
]
Medications
* Loop
Loop or LOOP may refer to:
Brands and enterprises
* Loop (mobile), a Bulgarian virtual network operator and co-founder of Loop Live
* Loop, clothing, a company founded by Carlos Vasquez in the 1990s and worn by Digable Planets
* Loop Mobile, an ...
and thiazide diuretic
Thiazide () refers to both a class of sulfur-containing organic molecules and a class of diuretics based on the chemical structure of benzothiadiazine. The thiazide drug class was discovered and developed at Merck and Co. in the 1950s. The firs ...
use (the most common cause of hypomagnesemia)
* Antibiotics (i.e. aminoglycoside
Aminoglycoside is a medicinal and bacteriologic category of traditional Gram-negative antibacterial medications that inhibit protein synthesis and contain as a portion of the molecule an amino-modified glycoside (sugar). The term can also refer ...
, amphotericin
Amphotericin B is an antifungal medication used for serious mycosis, fungal infections and leishmaniasis. The fungal infections it is used to treat include mucormycosis, aspergillosis, blastomycosis, candida infections, candidiasis, coccidioidomy ...
, pentamidine, gentamicin, tobramycin
Tobramycin is an aminoglycoside antibiotic derived from '' Streptomyces tenebrarius'' that is used to treat various types of bacterial infections, particularly Gram-negative infections. It is especially effective against species of ''Pseudomonas ...
, viomycin) block resorption in the loop of Henle. 30% of patients using these antibiotics have hypomagnesemia.
* Long term, high dosage use of proton-pump inhibitors such as omeprazole
Omeprazole, sold under the brand names Prilosec and Losec, among others, is a medication used in the treatment of gastroesophageal reflux disease (GERD), peptic ulcer disease, and Zollinger–Ellison syndrome. It is also used to prevent upp ...
* Other drugs
** Digitalis
''Digitalis'' ( or ) is a genus of about 20 species of herbaceous perennial plants, shrubs, and biennials, commonly called foxgloves.
''Digitalis'' is native to Europe, western Asia, and northwestern Africa. The flowers are tubular in shap ...
, displaces magnesium into the cell. Digitalis causes an increased intracellular concentration of sodium, which in turn increases intracellular calcium by passively increasing the action of the sodium-calcium exchanger in the sarcolemma
The sarcolemma (''sarco'' (from ''sarx'') from Greek; flesh, and ''lemma'' from Greek; sheath) also called the myolemma, is the cell membrane surrounding a skeletal muscle fiber or a cardiomyocyte.
It consists of a lipid bilayer and a thin oute ...
. The increased intracellular calcium gives a positive inotropic
An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction.
The term ''inotro ...
effect.
** Adrenergics, displace magnesium into the cell
** Cisplatin
Cisplatin is a chemotherapy medication used to treat a number of cancers. These include testicular cancer, ovarian cancer, cervical cancer, breast cancer, bladder cancer, head and neck cancer, esophageal cancer, lung cancer, mesothelioma, ...
, stimulates kidney excretion
** Ciclosporin
Ciclosporin, also spelled cyclosporine and cyclosporin, is a calcineurin inhibitor, used as an immunosuppressant medication. It is a natural product. It is taken orally or intravenously for rheumatoid arthritis, psoriasis, Crohn's disease ...
, stimulates kidney excretion
** Mycophenolate mofetil
Mycophenolic acid (MPA) is an immunosuppressant medication used to prevent rejection following organ transplantation and to treat autoimmune conditions such as Crohn's disease and lupus. Specifically it is used following kidney, heart, and liv ...
Genetics
* Gitelman-like diseases, which include the syndromes caused by genetic mutations
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitos ...
in '' SLC12A3'', '' CLNCKB'', ''BSND
Bartter syndrome, infantile, with sensorineural deafness (Barttin), also known as BSND, is a human gene which is associated with Bartter syndrome.
This gene encodes an essential beta subunit for CLC chloride channels. These heteromeric channels l ...
'', '' KCNJ10'', '' FXYD2'', ''HNF1B
HNF1 homeobox B (hepatocyte nuclear factor 1 homeobox B), also known as HNF1B or transcription factor 2 (TCF2), is a human gene.
Function
HNF1B encodes hepatocyte nuclear factor 1-beta, a protein of the homeobox-containing basic helix-turn-hel ...
'' or '' PCBD1''. In these diseases, the hypomagnesemia is accompanied by other defects in electrolyte handling such as hypocalciuria and hypokalemia
Hypokalemia is a low level of potassium (K+) in the blood serum. Mild low potassium does not typically cause symptoms. Symptoms may include feeling tired, leg cramps, weakness, and constipation. Low potassium also increases the risk of an abno ...
. The genes involved in this group of diseases all encode proteins that are involved in reabsorbing electrolytes (including magnesium) in the distal convoluted tubule
The distal convoluted tubule (DCT) is a portion of kidney nephron between the loop of Henle and the collecting tubule.
Physiology
It is partly responsible for the regulation of potassium, sodium, calcium, and pH.
On its apical surface (lumen ...
of the kidney.
* Hypercalciuric hypomagnesemic syndromes, which encompass the syndromes caused by mutations in ''CLDN16
Claudin-16 is a protein that in humans is encoded by the ''CLDN16'' gene. It belongs to the group of claudins.
Tight junctions represent one mode of cell-to-cell adhesion in epithelial or endothelial cell sheets, forming continuous seals around c ...
'', ''CLDN19
Claudin-19 is a protein that in humans is encoded by the ''CLDN19'' gene. It belongs to the group of claudin
Claudins are a family of proteins which, along with occludin, are the most important components of the tight junctions ( zonulae occlu ...
'', '' CASR'' or ''CLCNKB
Chloride channel Kb, also known as CLCNKB, is a protein which in humans is encoded by the ''CLCNKB'' gene.
Chloride channel Kb (CLCNKB) is a member of the CLC family of voltage-gated chloride channels, which comprises at least 9 mammalian chlori ...
''. In these diseases, reabsorption of divalent cations
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules.
Description
The combining capacity, or affinity of an ...
(such as magnesium and calcium) in the thick ascending limb of Henle's loop of the kidney is impaired. This results in loss of magnesium and calcium in the urine.
* Mitochondriopathies, especially mutations in the mitochondrial tRNAs '' MT-TI'' or '' MT-TF.'' Mutations in '' SARS2,'' or mitochondrial DNA deletions as seen with Kearns-Sayre syndrome, can also cause hypomagnesemia.
* Other genetic causes of hypomagnesemia, such as mutations in '' TRPM6'', '' CNNM2'', '' EGF'', '' EGFR'', '' KCNA1'' or '' FAM111A''. Many of the proteins encoded by these genes play a role in the transcellular
Transcellular transport involves the transportation of solutes by a cell ''through'' a cell. Transcellular transport can occur in three different ways active transport, passive transport, and transcytosis.
Active Transport
Main article: Active ...
absorption of magnesium in the distal convoluted tubule.
Metabolic abnormalities
* Insufficient selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
, vitamin D or sunlight exposure, or vitamin B6
Vitamin B6 is one of the B vitamins, and thus an essential nutrient. The term refers to a group of six chemically similar compounds, i.e., " vitamers", which can be interconverted in biological systems. Its active form, pyridoxal 5′-phosp ...
.
* Gastrointestinal causes: the distal digestive tract secretes high levels of magnesium. Therefore, secretory diarrhea can cause hypomagnesemia. Thus, Crohn's disease, ulcerative colitis
Ulcerative colitis (UC) is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and ...
, Whipple's disease
Whipple's disease is a rare systemic infectious disease caused by the bacterium '' Tropheryma whipplei''. First described by George Hoyt Whipple in 1907 and commonly considered as a gastrointestinal disorder, Whipple's disease primarily causes ma ...
and celiac sprue
Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...
can all cause hypomagnesemia.
* Postobstructive diuresis, diuretic phase of acute tubular necrosis
Acute tubular necrosis (ATN) is a medical condition involving the death of tubular epithelial cells that form the renal tubules of the kidneys. Because necrosis is often not present, the term acute tubular injury (ATI) is preferred by pathologists ...
(ATN) and kidney transplant
Kidney transplant or renal transplant is the organ transplant of a kidney into a patient with end-stage kidney disease (ESRD). Kidney transplant is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantati ...
.
Other
* Chronic alcoholism
Alcoholism is, broadly, any drinking of alcohol that results in significant mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognized diagnostic entity. Predomin ...
: Alcohol intake leads to enhanced diuresis of electrolytes. Chronic consumption leads to the depletion of body stores of magnesium.
* Acute myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may t ...
: within the first 48 hours after a heart attack, 80% of patients have hypomagnesemia. This could be the result of an intracellular shift because of an increase in catecholamine
A catecholamine (; abbreviated CA) is a monoamine neurotransmitter, an organic compound that has a catechol (benzene with two hydroxyl side groups next to each other) and a side-chain amine.
Catechol can be either a free molecule or a su ...
s.
* Malabsorption
Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety ...
* Acute pancreatitis
Acute pancreatitis (AP) is a sudden inflammation of the pancreas. Causes in order of frequency include: 1) a gallstone impacted in the common bile duct beyond the point where the pancreatic duct joins it; 2) heavy alcohol use; 3) systemic disea ...
* Fluoride poisoning
* Massive transfusion (MT) is a lifesaving treatment of hemorrhagic shock
Hypovolemic shock is a form of shock caused by severe hypovolemia (insufficient blood volume or extracellular fluid in the body). It could be the result of severe dehydration through a variety of mechanisms or blood loss. Hypovolemic shock is a m ...
, but can be associated with significant complications.
Pathophysiology
Magnesium is a co-factor in over 300 functions in the body regulating many kinds of biochemical reactions. It is involved in protein synthesis, muscle and nerve functioning, bone development, energy production, the maintenance of normal heart rhythm, and the regulation of glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...
and blood pressure, among other important roles. Low magnesium intake over time can increase the risk of illnesses, including high blood pressure and heart disease, diabetes mellitus type 2, osteoporosis, and migraines.[
There is a direct effect on sodium (Na), potassium (K), and calcium (Ca) channels. Magnesium has several effects:
]
Potassium
Potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...
channel efflux is inhibited by magnesium. Thus hypomagnesemia results in an increased excretion of potassium in kidney, resulting in a hypokalaemia. This condition is believed to occur secondary to the decreased normal physiologic magnesium inhibition of the ROMK
The renal outer medullary potassium channel (ROMK) is an ATP-dependent potassium channel (Kir1.1) that transports potassium out of cells. It plays an important role in potassium recycling in the thick ascending limb (TAL) and potassium secretion ...
channels in the apical tubular membrane.
In this light, hypomagnesemia is frequently the cause of hypokalaemic patients failing to respond to potassium supplementation. Thus, clinicians should ensure that both magnesium and potassium is replaced when deficient. Patients with diabetic ketoacidosis
Diabetic ketoacidosis (DKA) is a potentially life-threatening complication of diabetes mellitus. Signs and symptoms may include vomiting, abdominal pain, deep gasping breathing, increased urination, weakness, confusion and occasionally loss of ...
should have their magnesium levels monitored to ensure that the serum loss of potassium, which is driven intracellularly by insulin administration, is not exacerbated by additional urinary losses.
Calcium
Release of calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
from the sarcoplasmic reticulum
The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the smooth endoplasmic reticulum in other cells. The main function of the SR is to store calcium ions (Ca2+). Calcium ion levels are ke ...
is inhibited by magnesium. Thus hypomagnesemia results in an increased intracellular calcium level. This inhibits the release of parathyroid hormone
Parathyroid hormone (PTH), also called parathormone or parathyrin, is a peptide hormone secreted by the parathyroid glands that regulates the serum calcium concentration through its effects on bone, kidney, and intestine.
PTH influences bone ...
, which can result in hypoparathyroidism
Hypoparathyroidism is decreased function of the parathyroid glands with underproduction of parathyroid hormone (PTH). This can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany (involuntary m ...
and hypocalcemia
Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mm ...
. Furthermore, it makes skeletal and muscle receptors less sensitive to parathyroid hormone.
Arrhythmia
Magnesium is needed for the adequate function of the Na+/K+-ATPase pumps in cardiac myocytes, the muscles cells of the heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...
. A lack of magnesium inhibits reuptake of potassium, causing a decrease in intracellular potassium. This decrease in intracellular potassium results in a tachycardia
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ( ...
.
Pre-eclampsia
Magnesium has an indirect antithrombotic effect upon platelets and endothelial function. Magnesium increases prostaglandins, decreases thromboxane
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring.
Thromboxane is named for i ...
, and decreases angiotensin II, microvascular leakage, and vasospasm through its function similar to calcium channel blockers. Convulsions are the result of cerebral vasospasm. The vasodilatatory effect of magnesium seems to be the major mechanism.
Asthma
Magnesium exerts a bronchodilatatory effect, probably by antagonizing calcium-mediated bronchoconstriction.
Neurological effects
*reducing electrical excitation
*modulating release of acetylcholine
*antagonising ''N''-methyl-D-aspartate (NMDA
''N''-methyl--aspartic acid or ''N''-methyl--aspartate (NMDA) is an amino acid derivative that acts as a specific agonist at the NMDA receptor mimicking the action of glutamate, the neurotransmitter which normally acts at that receptor. Unlike ...
) glutamate receptors, an excitatory neurotransmitter of the central nervous system and thus providing neuroprotection from excitoxicity.
Diabetes mellitus
Magnesium deficiency is frequently observed in people with type 2 diabetes mellitus, with an estimated prevalence ranging between 11.0 and 47.7%.
Magnesium deficiency is strongly associated with high glucose and insulin resistance, which indicate that it is common in poorly controlled diabetes. Patients with type 2 diabetes and a magnesium deficiency have a higher risk of heart failure, atrial fibrillation and microvascular complications. Oral magnesium supplements has been demonstrated to improve insulin sensitivity and lipid profile. A 2016 meta-analysis not restricted to diabetic subjects found that increasing dietary magnesium intake, while associated with a reduced risk of stroke, heart failure, diabetes, and all-cause mortality, was not clearly associated with lower risk of coronary heart disease (CHD) or total cardiovascular disease (CVD).
A 2021 study on blood from 4,400 diabetic patients over 6 to 11 years reported that "People with higher levels of magnesium in the blood were found to have a significantly lower risk of cardiovascular disease", and also of diabetic foot and diabetic retinopathy. The researchers, however, stated that "we have otdemonstrated that magnesium supplements work. Further research is needed."
Homeostasis
Magnesium is abundant in nature. It can be found in green vegetables, chlorophyll (chloroplasts), cocoa derivatives, nuts, wheat, seafood, and meat. It is absorbed primarily in the duodenum of the small intestine. The rectum and sigmoid colon can absorb magnesium. Forty percent of dietary magnesium is absorbed. Hypomagnesemia stimulates and hypermagnesemia inhibits this absorption.
The body contains 21–28 grams of magnesium (0.864–1.152 mol). Of this, 53% is located in bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...
, 19% in non-muscular tissue, and 1% in extracellular fluid
In cell biology, extracellular fluid (ECF) denotes all body fluid outside the cells of any multicellular organism. Total body water in healthy adults is about 60% (range 45 to 75%) of total body weight; women and the obese typically have a low ...
. For this reason, blood levels of magnesium are not an adequate means of establishing the total amount of available magnesium.
The majority of serum magnesium is bound to chelators, including protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
s and citrate
Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in the ...
. Roughly 33% is bound to proteins, and 5–10% is not bound. This "free" magnesium is essential in regulating intracellular magnesium. Normal plasma Mg is 1.7–2.3 mg/dL (0.69–0.94 mmol/L).
The kidney
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blo ...
s regulate the serum magnesium. About 2400 mg of magnesium passes through the kidneys daily, of which 5% (120 mg) is excreted through urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra.
Cellular ...
. The loop of Henle
In the kidney, the loop of Henle () (or Henle's loop, Henle loop, nephron loop or its Latin counterpart ''ansa nephroni'') is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. Named after its ...
is the major site for magnesium homeostasis, and 60% is reabsorbed.
Magnesium homeostasis comprises three systems: kidney, small intestine, and bone. In the acute phase of magnesium deficiency there is an increase in absorption in the distal small intestine and tubular resorption in the kidneys. When this condition persists, serum magnesium drops and is corrected with magnesium from bone tissue. The level of intracellular magnesium is controlled through the reservoir in bone tissue.
Diagnosis
Magnesium deficiency or depletion is a low level of magnesium; it is not easy to measure directly.[ Typically the diagnosis is based on finding hypomagnesemia, a low magnesium level, which often reflects low body magnesium;][ however, magnesium deficiency can be present without hypomagnesemia, and vice versa.] A plasma magnesium concentration of less than 0.6 mmol/L (1.46 mg/dL) is considered to be hypomagnesemia;[ severe disease generally has a level of less than 0.50 mmol/L (1.25 mg/dL).][
]
Electrocardiogram
The electrocardiogram (ECG) change may show a tachycardia with a prolonged QT interval. Other changes may include prolonged PR interval, ST segment depression, flipped T waves, and long QRS duration.[
]
Treatments
Treatment of magnesium deficiency depends on the degree of deficiency and the clinical effects. Replacement by mouth is appropriate for people with mild symptoms, while intravenous replacement is recommended for people with severe effects.
Numerous oral magnesium preparations are available. In two trials of magnesium oxide, one of the most common forms in magnesium dietary supplements because of its high magnesium content per weight, was found to be less bioavailable than magnesium citrate
Magnesium citrate is a magnesium preparation in salt form with citric acid in a 1:1 ratio (1 magnesium atom per citrate molecule). The name "magnesium citrate" is ambiguous and sometimes may refer to other salts such as trimagnesium citrate wh ...
, chloride, lactate or aspartate. Amino-acid chelate was also less bioavailable.
Intravenous magnesium sulfate
Magnesium sulfate or magnesium sulphate (in English-speaking countries other than the US) is a chemical compound, a salt with the formula , consisting of magnesium cations (20.19% by mass) and sulfate anions . It is a white crystalline solid, ...
(MgSO4) can be given in response to heart arrhythmias to correct for hypokalemia
Hypokalemia is a low level of potassium (K+) in the blood serum. Mild low potassium does not typically cause symptoms. Symptoms may include feeling tired, leg cramps, weakness, and constipation. Low potassium also increases the risk of an abno ...
, preventing pre-eclampsia, and has been suggested as having a potential use in asthma.[
]
Food
Food sources of magnesium include leafy green vegetables, beans, nuts, and seeds.
Epidemiology
The condition is relatively common among people in hospital.[
]
History
Magnesium deficiency in humans was first described in the medical literature in 1934.
Plants
Magnesium deficiency is a detrimental plant disorder that occurs most often in strongly acidic, light, sandy soils, where magnesium can be easily leached away. Magnesium is an essential macronutrient constituting 0.2-0.4% of plants' dry matter and is necessary for normal plant growth. Excess potassium, generally due to fertilizers, further aggravates the stress from magnesium deficiency, as does aluminium toxicity.
Magnesium has an important role in photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
because it forms the central atom of chlorophyll. Therefore, without sufficient amounts of magnesium, plants begin to degrade the chlorophyll in the old leaves. This causes the main symptom of magnesium deficiency, interveinal chlorosis
In botany, chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow, or yellow-white. The affected plant has little or no ability to ...
, or yellowing between leaf veins, which stay green, giving the leaves a marbled appearance. Due to magnesium's mobile nature, the plant will first break down chlorophyll in older leaves and transport the Mg to younger leaves which have greater photosynthetic needs. Therefore, the first sign of magnesium deficiency is the chlorosis of old leaves which progresses to the young leaves as the deficiency progresses. Magnesium also acts as an activator for many critical enzymes, including ribulosebisphosphate carboxylase (RuBisCO
Ribulose-1,5-bisphosphate carboxylase-oxygenase, commonly known by the abbreviations RuBisCo, rubisco, RuBPCase, or RuBPco, is an enzyme () involved in the first major step of carbon fixation, a process by which atmospheric carbon dioxide is con ...
) and phosphoenolpyruvate carboxylase
Phosphoenolpyruvate carboxylase (also known as PEP carboxylase, PEPCase, or PEPC; , PDB ID: 3ZGE) is an enzyme in the family of carboxy-lyases found in plants and some bacteria that catalyzes the addition of bicarbonate (HCO3−) to phosphoenol ...
(PEPC), both essential enzymes in carbon fixation. Thus low amounts of Mg lead to a decrease in photosynthetic and enzymatic activity within the plants. Magnesium is also crucial in stabilizing ribosome structures, hence, a lack of magnesium causes depolymerization Depolymerization (or depolymerisation) is the process of converting a polymer into a monomer or a mixture of monomers. This process is driven by an increase in entropy.
Ceiling temperature
The tendency of polymers to depolymerize is indicated by ...
of ribosomes leading to premature aging of the plant. After prolonged magnesium deficiency, necrosis and dropping of older leaves occurs. Plants deficient in magnesium also produce smaller, woodier fruits.
Magnesium deficiency in plants may be confused with zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
or chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
deficiencies, viruses, or natural aging, since all have similar symptoms. Adding Epsom salts
Magnesium sulfate or magnesium sulphate (in English-speaking countries other than the US) is a chemical compound, a salt with the formula , consisting of magnesium cations (20.19% by mass) and sulfate anions . It is a white crystalline solid, s ...
(as a solution of 25 grams per liter or 4 oz per gal) or crushed dolomitic limestone to the soil can rectify magnesium deficiencies. An organic treatment is to apply compost mulch
A mulch is a layer of material applied to the surface of soil. Reasons for applying mulch include conservation of soil moisture, improving fertility and health of the soil, reducing weed growth and enhancing the visual appeal of the area.
A mu ...
, which can prevent leaching during excessive rainfall and provide plants with sufficient amounts of nutrients, including magnesium.
See also
*Magnesium in biology
Magnesium is an essential element in biological systems. Magnesium occurs typically as the Mg2+ ion. It is an essential mineral nutrient (i.e., element) for life and is present in every cell type in every organism. For example, adenosine triphos ...
*Hypermagnesemia
Hypermagnesemia is an electrolyte disorder in which there is a high level of magnesium in the blood. Symptoms include weakness, confusion, decreased breathing rate, and decreased reflexes. Complications may include low blood pressure and cardia ...
, high level of magnesium in blood
References
External links
Magnesium
{{Nutritional pathology
Magnesium
Mineral deficiencies
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