Magnesium

Magnesium is essential for the activation of several important enzyme reactions, including those that transfer phosphate from adenosine triphosphate (ATP) to adenosine diphosphate (ADP). ATP-ADP reactions are basic to all life processes.

Cardiac and skeletal muscles must have a correct balance of calcium and magnesium in order to function properly. Nerve transmission also depends on the balance between calcium and magnesium in the blood.

Low levels of magnesium in body fluids increase nerve conduction, and by stepping up the transmission of nerve impulses, these low levels increase muscular irritability and contractibility. In a severe deficiency, muscle tremors, uncontrolled movements of the hands and the face, and convulsions can occur.

Magnesium deficiency can result in an imbalance in calcium metabolism, with the mineral being deposited in the soft tissues. Bone deformities also occur. Magnesium deficiency also leads to degeneration of the kidneys, skeletal and cardiac muscle, endocardium, skin, and teeth. Blood levels of calcium and potassium are depressed. Sodium accumulates in the tissues, and edema results. And remember, local tissue deficiencies of magnesium can occur without blood levels falling below normal.

In animals, magnesium deficiency diminishes the ability to adapt to cold. Deficient animals suffer ulceration, calcification of the kidney, heart and blood vessels, damage to the heart, and reduced lifespan. In some experiments, magnesium deficiency caused seizures and a reduced motivation to learn in rats. When the animals were forced to perform in order to survive, they did. But voluntary activity was markedly impaired.

In humans, magnesium deficiency can cause a wide variety of symptoms, including lethargy, muscular weakness, knotting of muscle and nerve fibers (fasciculation), gross tremors, tetany, writhing movements of the hands, irritability, mental changes, convulsions, stupor, coma, dizziness, psychotic behavior, exaggeration of the reflexes, jerks, and seizures. In babies and children, magnesium deficiency can cause loss of appetite, growth failure, apathy, irritability, hallucinations, confusion, weakness, flaccidity, occasional spasticity and rigidity, tremors, twitches, apnea (breathing stops), and rapid pulse. Some researchers believe there may be a connection between magnesium deficiency and sudden infant death syndrome.

Neonatal tetany (convulsions) often results from a magnesium deficiency, even though the major biochemical sign is low calcium levels in the blood. These infants will often respond to magnesium supplementation (injected) better than to calcium, presumably because the magnesium deficiency is causing the severe drop in blood levels of calcium.  And magnesium can be crucial to calcium metabolism; rickets will sometimes respond to magnesium supplementation after massive doses of vitamin D have failed.

Where is it found ?

Natural foods all contain some magnesium. Rich sources include legumes, nuts, and whole grains. Meats are relatively poor sources, although shellfish are high in magnesium. Magnesium is removed from grains and many other foods when they are refined, so white flour is a poor source of magnesium, as are other refined grains.

Who is likely to be deficient ?

Magnesium deficiency is common in people taking "potassium-depleting" prescription medications. Taking too many laxatives can also lead to deficiency. Alcoholism, severe burns, diabetes, and heart failure are other potential causes of deficiency.

Almost two-thirds of people in intensive care hospital units have been found to be magnesium deficient. Deficiency is also associated with chronic diarrhea, pancreatitis, and other conditions associated with malabsorption.

Fatigue, abnormal heart rhythms, muscle weakness and spasm, depression, loss of appetite, listlessness, and potassium depletion can all result from a magnesium deficiency.

Deficiencies of magnesium that are serious enough to cause symptoms should be treated by medical doctors, as they might require intravenous administration of magnesium.

How much to take

The RDA for magnesium ranges from sixty mg. for infants up to 450 mg. for pregnant or lactating women. For adult men it is 350 mg.; for adult women, 300 mg.

Side effects

Taking too much magnesium often leads to diarrhea. For some people this can happen with amounts as low as 350-500 mg per day. More serious problems can develop with excessive magnesium intake from magnesium-containing laxatives; however, the amounts of magnesium found in nutritional supplements are unlikely to cause such problems. People with kidney disease should not take magnesium supplements without consulting a doctor.

Back To Top