By Annette R. Karnash, R.N., M.N.
Of all the essential minerals necessary to maintain life, magnesium is perhaps the most important for preventing and reversing signs of neural and neuromuscular over-excitement. Magnesium is a key element in stabilizing the nerve cell. Without it, the nerve would be in a constant state of excitement.
Magnesium is usually a part of a salt such as magnesium hydroxide, or “Milk of magnesia”, magnesium sulfate or “Epsom Salts”, both of which are used to treat G.I. disorders. Magnesium carbonate is a key ingredient in arthritis strength “Bufferin”.
Magnesium gets its name from the Greek city of Magnesia, where huge amounts of magnesium carbonate, used as a laxative during the Italian Renaissance were located. Magnesium is the central element in the chlorophyll molecule. Magnesium has a role in regulating the distribution of electrolytes and nutrients. It is used to treat heart attacks and Congestive Heart Failure and magnesium deficiency is associated with these conditions and with diabetes. Emphasis is placed on obtaining adequate calcium and Vitamin D to prevent or treat osteoporosis, yet not often are we instructed to increase magnesium. Magnesium and calcium compete for the same absorption sites in the G.I. tracts, so that high concentrations of one or the other results in poor absorption of the lesser. If calcium intake is increased magnesium should also be increased. Since calcium is an activator as in muscle contraction and nerve excitability, magnesium is a depressor, as in muscle and nerve relaxation. They counterbalance one another.
Magnesium may be an under diagnosed and under appreciated electrolyte irregularity, especially for patients with cardiovascular disease and diabetes. Some of the drugs used to treat hypertension, thiazide diuretics, may add to the problem associated with magnesium deficiency. Magnesium deficiency may be due to urinary magnesium loss secondary to chronic glycosuria. Replenishment and maintenance of both intracellular and extracellular magnesium levels need consideration. Magnesium is second to potassium as the most abundant intracellular cation in the body. It is part of chemical reaction that involves the formation and utilization of adenosine triphosphate (ATP) which the body uses for energy storage and transfer. As a co-factor of many enzymes its roles has been implicated in glucose utilization. Magnesium is a factor in over 30 enzymatic reactions, such as Na, K. ATPase pump activity, which is important in keeping intracellular and extracellular ionic concentrations balanced. Magnesium deficiency impairs this pump, resulting in potassium depletion and sodium accumulation.
The recommended daily allowance (RDA) of magnesium is 5mg/kg body weight and the average American diet provides only about 150 mg of the 400mg recommendation. Foods highest in magnesium, such as nuts, dried fruits, green vegetables, fish and whole grains, do not make up a major portion of the American diet. Appropriate meal plans for diabetic patients may also restrict a number of foods in this group due to the sugar, cholesterol and high caloric content. Factors such as pregnancy, aging and stress can increase magnesium requirements through impaired absorption, decreased renal function and increased cellular magnesium elimination. Several renal, endocrine and gastro-intestinal conditions may cause hypomagnesemia. Because magnesium chloride is highly soluble, it will reach the small intestine, the site of maximal absorption, as free magnesium ions, a form necessary for uptake. Other magnesium salts are relatively insoluble and provide less free magnesium for absorption and chloride appears to improve magnesium absorption. Health care professionals should be alert for patients who may be at risk for magnesium deficiency, especially patients with co-existing diabetes and cardio-vascular disease. They may benefit from magnesium supplementation.
