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Magnesium

Involved in more than 300 enzymatic systems and is the fourth most abundant cation in the body.

Magnesium is involved in major cellular and physiological processes primary through its nucleotide binding properties and its regulation of enzymatic activity.

All ATPase reactions require a magnesium ion-ATP including those involved in RNA and DNA functions and is a cofactor for hundreds of enzymatic reactions in every cell type.

Typically exist as the magnesium 2+ ion.

Its present in all cells and indispensable for health and life, as it is an essential cofactor for ATP, the cellular source of energy.

Divalent cation.

Plays role in cellular energy transfer, storage and utilization.

Involved in fat, protein and carbohydrate metabolism.

Helps to maintain normal cell membrane function.

Helps regulate parathyroid hormone secretion.

Magnesium (Mg) is a chemical element with atomic number 12 and is the eleventh most abundant element by mass in the human body.

Magnesium is involved in the control of neuromuscular function, regulation of cardiac rhythm, modulation of vascular tone, hormone secretion, and N-methyl-D-aspartate release in the CNS.

Measure magnesium is a second messenger involved in intracellular signaling, and a regulator of the circadian clock which controls rhythm in biologic systems.

Magnesium transporters are gatekeepers of human magnesium homeostasis.

Magnesium is regulated primarily by the intestine, where dietary magnesium absorption is regulated, the bone which stores magnesium as hydroxylapatite, and the kidney which regulates urinary magnesium excretion.

It is an essential part of healthy nutrition.

Lesss than 30 percent of adults in the U.S. meet their daily need.

One in five get only half of what is required to maintain good health.

Essential for the maintenance of genomic stability, DNA repair and has a role in modulating cell proliferation cell cycle progression and cell differentiation.

Essential for DNA and protein synthesis, neurotransmission and hormone receptor binding.

Normal serum magnesium concentrations range between 0.75 and 0.95 millimoles (mmol)/L, less than 0.03% and does not reflect them body’s overall magnesium level.

Normal body stores 21-28 gm with 50% of the body’s stores in the skeleton bone mass, and soft tissues.

More than 60% of the body’s  magnesium stores reside in bone, and nearly 70% of serum magnesium circulates freely, not bound to plasma proteins.

In plasma 30% of the circulating magnesium is bound to proteins,nmostly through free fatty acids.

Patient with chronically high levels of free fatty acids generally have a lower blood magnesium concentration.

Plasma magnesium levels are inversely proportional to the risk of cardiovascular and metabolic diseases.

Unbound in magnesium is freely filtered at the glomerulus and it enters the tubules where more than 95% of filtered magnesium is reabsorbed by the kidneys.
 
Magnesium is reabsorbed primarily at the ascending loop of Henle, and the last site of regulation is the distal convoluted tubule, were a positive lumen potential is required for reabsorption paracellularly.
 

Second most abundant intracellular cation after potassium.

Total body content 2000 mEq, 25 g. or 1000 mmol.

Approximately 60% of body’s magnesium in bone and 20% in muscle and 20% in soft tissues and liver.

Exchangeable magnesium in bone provides a dynamic reservoir to maintain plasma concentrations, and it can influence bone formation by influencing activation of osteoblasts and osteoclasts.

High magnesium intake results increased bone mineral content, reducing the risk of bone fractures and osteoporosis during aging.

Intracellular concentration 40 mEq/L.

Greatest concentration within the cell.

Only 1% of the body magnesium is extracellular, with one half ionized and 25-30% protein bound.

Less than one percent of magnesium in the body is in plasma, and therefore plasma magnesium is not a reliable marker of total content in body tissues.

Approximately 99% of total body magnesium is intracellular or in bone.

Intracellular magnesium ion, is second only to potassium as the most abundant intracellular cation.

In cells 90 to 95% of magnesium is found to ligands ATP, ADP, citrate, proteins, and nucleic acids.

Only one to 5% of intracellular magnesium exists as free magnesium.

Intracellular free magnesium is 1.2 to 2.9 mg per dL, similar to the extracellular concentration.

80% of plasma magnesium ionized or complexed to filterable ions including oxalate, phosphate, and citrate, and is available for glomerular filtration.

Low levels have been linked with stress and anxiety.

The kidneys play a major role in processing magnesium in the body by filtering and excreting it, along with other minerals.

Only 20% of magnesium is reabsorbed in the proximal tubule, where most magnesium at 70% is taken up by the ascending limb of the loop of Henle.

Caffeine triggers the kidneys to release Mg, further lowering magnesium levels.

Homeostasis related to gastrointestinal absorption and renal excretion.

Dark-colored carbonated soda has phosphates which block the body from using it by chemically binding with magnesium that is present in the gut.

Carbonated soda flushes magnesium from food before the body can use it.

Refined sugar in many bakery items and is also present in processed foods and provides no Mg.

Average diet has 360 mg of magnesium daily and ingestion of 0.15-.02 mmol/kg/d is required to maintain balance.

Adequate levels have been reported to reduce the risk of inflammation, colorectal cancer, stroke, diabetes, and cardiovascular events.

Deficiency has been implicated in diabetes, hyperlipidemia, hypertension, cardiac arrhythmias, acute myocardial infarction, atherosclerosis and sudden cardiac death.

The presence of hypertension might indicate a magnesium deficiency.

Mg dilates and relaxes blood vessels, and constricted blood vessels drive up the blood pressure.

Stabilizes abnormal nerve excitation or blood vessel spasm in medical conditions such as eclampsia.

Low Mg levels can make it difficult for the coronary muscle to contract.

Low magnesium levels cause the intestines to contract which constricts waste materials, causing constipation.

The benefits of Mg for proper bowel elimination is two-fold: first, it helps to relax the bowel muscles, and uses osmosis to pull water into the bowel tissues.

Alcohol acts as a diuretic and increases the excretion of magnesium via the kidneys.

Excessive alcoholol slows the digestive system and creates a vitamin D deficiency, both of which can lower Mg levels.

The burdens of daily life or the trauma of recovery from a major medical operation remove Mg from the body.

Paradoxically, too little magnesium creates stress and stress lowers magnesium levels.

The body uses magnesium in stressful conditions, chronic or acute, and needs replenishment.

Signs of magnesium deficiency are poor sleep, chronic pain, and facial tics, anxiety, depression and cramps.

Deficiency causes insulin resistance.

Incidence of deficiency in general population 6.9%, in hospital-inpatients 11%, in ICU patients 60%, in diabetic patients 25%, and 24% in hypertensive patients

Magnesium is found in all sorts of food.

Pumpkin seeds: 46% of the RDI in a quarter cup (16 grams)

Spinach boiled: 39% of the RDI in a cup (180 grams)

Swiss chard boiled: 38% of the RDI in a cup (175 grams)

Dark chocolate (70–85% cocoa): 33% of the RDI in 3.5 ounces (100 grams)

Black beans: 30% of the RDI in a cup (172 grams)

Quinoa, cooked: 33% of the RDI the in a cup (185 grams)

Halibut: 27% of the RDI in 3.5 ounces (100 grams)

Almonds: 25% of the RDI in a quarter cup (24 grams)

Cashews: 25% of the RDI in a quarter cup (30 grams)

Mackerel: 19% of the RDI in 3.5 ounces (100 grams)

Avocado: 15% of the RDI in one medium avocado (200 grams)

Salmon: 9% of the RDI in 3.5 ounces (100 grams)

Nutritional sources are legumes, leafy vegetables, nuts, chocolate and animal protein.

Vegetables, fruits, meats and fish have intermediate magnesium values.

Cooking may deplete magnesium content.

Serum levels correlate poorly with total body stores.

Recommended daily allowance of dietary magnesium 420 mg/day.

Dietary sources rich in magnesium include: cereals, beans, nuts, and green vegetables.

Of the total dietary magnesium consumed 30 to 40% is absorbed in the intestine.

Intestinal, magnesium absorption is influenced by dietary, magnesium, intestinal, lumen, pH hormones, including estrogen and insulin, and parathormone and gut microbiota.

Maintains the antioxidative status of cells.

High magnesium intake may reduce the occurrence of colorectal cancer in women.

At high concentrations can mimic actions of calcium and can suppress PTH leading to a functional type of hypoparathyroidism and hypocalcemia.

Calcium taken as a dietary supplement is excellent for bone health but, unfortunately, reduces the body’s ability to absorb and retain magnesium.

Severe elevations seen in renal failure, magnesium antacid ingestion or following intravenous magnesium.

Hypokalemia is common in patients with hypomagnesia, and refractory potassium repletion is often linked to magnesium depletion is corrected only after the magnesium deficit has been normalized.

Magnesium deficiency increases renal, potassium loss by promoting potassium secretion in the collecting duct.

Hypomagnesemia inhibits PTH secretion and prevents PTH actions on the kidneys and the skeleton.

Necessary for parathyroid hormone production.

Systemically decreases blood pressure, and alters peripheral vascular resistance.

Hypomagnesemia leads to disturbances in almost every organ and causes ventricular arrhythmias, coronary artery vasospasm, and sudden death.

Can be replaced intramuscularly or intravenously trying to provide 24-48 meq/24 hours as magnesium sulfate.

Oral magnesium oxide available but in large doses cause diarrhea.

A component of chlorophyll.

Absorbed in the small intestine, mainly in the ileum, via active and passive transport mechanisms.

Excreted in the stool and urine.

Regulation of serum levels under renal control.

Most renal absorption occurs in the proximal tubule and the ascending limb of the loop of Henle.

In the presence of hypomagnesememia the kidney may excrete as little as 1 mEq/L.

In times of deficiency magnesium may be removed from bone.

Magnesium-rich foods include avocado, banana, dark leafy vegetables, dried fruits, lentils, and soybeans.

Recommending a daily oral magnesium supplement could help prevent asthma flare ups and reduce inhaler use among patients with the condition.

Half of population does not consume the recommended dietary allowance from their food.

Relax smooth muscle cells by reducing intracellular calcium and exhibits an anti-inflammatory effect by balancing T-cells and suppressing mast cells.

Inhibits acetylcholine release and nitric acid and prostacyclin synthesis to decrease muscle fiber excitability.

Use in asthma improves pulmonary function on the FEVI and FVC, decreases airway reactivity and wheezing, fewer

flare ups, fewer outpatient visits, less use of inhaled corticosteroids and decreases skin response to allergens.

IV magnesium administration for acute asthma exacerbations, adult doses ranging from more than 30 to 40 mg per day and for children doses ranging from 10 to 30 grams per day provided immediate relief for severe bronchospasm and airway inflammation

Checking magnesium blood levels in asthmatic patients and recommending daily use of magnesium supplements and use of a magnesium-rich diet as a prophylactic nonpharmacological treatment.

Current dietary guidelines recommend adult men consume 400-420 mg per day, adult women 300-320 mg per day, and children aged 9 to 12 years 200-300 mg per day.

A normal serum value is 1.7 to 2.4 mg/dL.

Hypomagnesemia is defined as a serum magnesium level below 1.7 mg/dL.

Most patients with borderline hypomagnesemia are asymptomatic.

Hypomagneemia is present 3 to 10% of the general population and its prevalence is increased among individuals with type two diabetes and hospitalized patients, especially those in the ICU.

Hypomagnesia is associated with an elevated risk of death from any cause and death from cardiovascular causes.

Oral magnesium supplement doses should be 300-400 mg per day for adults, and 200-300 mg per day for children.

Associated with less frequent asthma flare ups, and fewer outpatient visits

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