Magnesium Health Article

Description

Magnesium is an element (Mg) with an atomic weight of 24.312 and the atomic number 12. In its elemental form, magnesium is a light, silver-white metal. It is a cation, which means that its ion has a positive charge. Of the cations in the human body, magnesium is the fourth-most abundant. Ninety-nine percent of the body's magnesium is contained within its cells: about 60% in the bones, 20% in the muscles, 19%–20% in the soft tissue, and 1% circulates in the blood. Important to both nutrition and medicine, magnesium, like calcium and phosphorus, is considered a major mineral. Magnesium in its carbonate and sulfate forms has been used for centuries as a laxative. The name of the element comes from Magnesia, a city in Greece where large deposits of magnesium carbonate were discovered in ancient times.

Magnesium is an important element in the body because it activates or is involved in many basic processes or functions, including:

• cofactor for over 300 enzymes
• oxidation of fatty acids
• activation of amino acids
• synthesis and breakdown of DNA
• neurotransmission
• immune function
• interactions with other nutrients, including potassium, vitamin B₆, and boron

General use

Magnesium has a number of general uses, primarily in standard allopathic medicine, but also in some alternative therapies.

Nutrition

The Food and Nutrition Board of the National Academy of Sciences has established the following dietary reference intakes (DRIs) and tolerable upper limits (ULs) for magnesium: Infants and children 0–6 months, 30 mg; 7–12 months, 75 mg; 1–3 years, 80 mg; 4–8 years, 130 mg; 9–13 years 240 mg. Males 14–18 years, 410 mg; 19–30 years, 400 mg; over 30 years, 420 mg. Females 14–18 years, 360 mg; 19–30 years, 310 mg; over 30 years, 320 mg. The ULs apply only to magnesium taken as a dietary supplement or given for medical reasons, since no toxicity from magnesium occurring naturally in foods has been reported. The ULs for magnesium are: 1–3 years, 65 mg; 4–8 years, 110 mg; 9 years and over, 350 mg.

Good dietary sources of magnesium include nuts; dried peas and beans; whole grain cereals such as oatmeal, millet, and brown rice; dark green vegetables; bone meal; blackstrap molasses; brewer's yeast; and soy products. Dark green vegetables are important sources of magnesium because it is the central atom in the structure of chlorophyll. Drinking hard water or mineral water can also add magnesium to the diet.

A severe magnesium deficiency in a healthy person is unusual because normal kidneys are very efficient in keeping magnesium levels balanced. This condition, called hypomagnesemia, is usually caused either by disease (kidney disease, severe malabsorption, chronic diarrhea, hyperparathyroidism, or chronic alcoholism) or as a side effect of certain medications, most commonly diuretics, cisplatin (a cancer medication), and a few antibiotics. The symptoms of hypomagnesemia include disturbances of the heart rhythm, muscle tremors or twitches, seizures, hyperactive reflexes, and occasional personality changes (depression or agitation). A patient with hypomagnesemia may also produce Chvostek's sign, which is a facial spasm caused when the doctor taps gently over the facial nerve. This condition of painful intermittent muscle contractions and spasms is known as tetany. Hypomagnesemia can be treated with either oral or intravenous preparations containing magnesium.

Magnesium toxicity (hypermagnesemia) is rare because excessive amounts are usually excreted in the urine and feces. Most cases of hypermagnesemia are caused by overuse of dietary supplements containing magnesium. The symptoms of magnesium toxicity include central nervous system depression, muscle weakness, fatigue, and sleepiness. In extreme cases, hypermagnesemia can cause death. It can be treated with intra-venous calcium gluconate along with respiratory support. Severe hypermagnesemia can be treated by hemodialysis or peritoneal dialysis.