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Mineral Directory - Magnesium

DK PublishingDK Publishing 2/07/2014 DKBooks


Daily requirement
men: 420mg per day
women: 320mg per day

This mineral plays a vital role in the formation of bones and teeth and, with the minerals calcium, sodium, and potassium, is involved in transmitting nerve signals and causing muscle contractions. Magnesium (Mg) also helps the body process fat and protein and make proteins and is necessary for the secretion of parathyroid hormone, which helps control the levels of calcium in the blood. Vitamin D increases the absorption of potassium in the intestine. Once absorbed, magnesium is stored in bone, muscles, cells, and the fluid that surrounds cells.

Because of magnesium’s role in muscle contraction, it is used medically to reduce irregular heart rhythms (arrhythmias) or contractions of the uterus in pregnant women.

Magnesium deficiency

A dietary, or primary, deficiency of magnesium is rare. However, it can result from problems with the absorption of nutrients from the intestine, long-term use of diuretic medications, excessive vomiting, kidney disease, chronic alcohol abuse, hyperparathyroidism, and liver cirrhosis. Because magnesium is also needed for the normal functioning of the parathyroid glands, which secrete parathyroid hormone, low magnesium levels may adversely decrease the levels of calcium in the blood.

A magnesium deficiency leads to low levels of calcium and potassium in the blood, as well as changes to the digestive system, nervous and muscular systems, heart and circulatory systems, and the development of blood cells.

People who develop a magnesium deficiency may have the following signs and symptoms: fatigue, weakness, poor appetite, impaired speech, anemia, irregular heart rhythms, and tremors. Affected babies and young children may fail to thrive. Advanced signs of the deficiency include abnormally rapid heart rate and convulsions, and it may be fatal if not treated.

Good sources


This is found naturally in all the foods below, which contain at least 50mg of magnesium per 31/2oz (100g):

Whole grains




Swiss chard

Turnip greens

Lamb kidney

Red meat


Nuts such as Brazils, almonds, cashews, and peanuts

Sunflower seeds


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