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Author: Frank Murray
Source: Better Nutrition (1989-90), September 1989

Magnesium Is Important For Heart Health

In ancient times the Romans believed that magnesia alba, white magnesium salts from the region of Magnesia in Greece, possessed unusual curative powers. However, it was not until 1808 that Sir Humhrey Davy, a British chemist, isolated the substance in the salts which we now know as magnesium.

Magnesium is an essential mineral that makes up about 0.05 percent of the body’s weight, according to Foods and Nutrition Encyclopedia. From 30 to 50 percent of the average daily intake of magnesium is absorbed in the small intenstine. A high intake of calcium, phosphate, oxalic acid (spinach, rhubarb), phytate (whole-grain cereals), and poorly digested fats can interfere with magnesium absorption. Protein, lactose (milk sugar), vitamin D, growth hormone and antibiotics enhance magnesium absorption.

Most magnesium is excreted in the urine. Diuretics, which increase urination, deplete magnesium stores in the body. Caffeine, for example, increases the excretion of magnesium, calcium and sodium, according to researchers at Washington State University, Pullman. A study conducted by the University of Helsinki and the National Public Health Institute in Finland found that alcohol, another diuretic, lowers the amount of magnesium and selenium in the blood. After analyzing data from the 48 male and 37 female volunteers, all alcoholics, researchers determined that the increased alcohol intake was responsible for removing magnesium and selenium from the blood, since there was no indication that the subjects had overt dietary deficiencies.

A number of studies have reported the beneficial effects of magnesium for premenstrual syndrome (PMS). One group of PMS patients received from 4.5 to 6 grams of magnesium daily for one week prior to menstruation and for two days during menstruation. Nervous tension subsided in 89 percent of the patients, while 96 percent reported less painful breasts, according to Endocrinology.

One of the most commonly cited causes of PMS cravings is magnesium deficiency, and yet blood tests of PMS patients seldom reveal it, according to Douglas Hunt, M.D., in No More Fears. Magnesium often is low in the cells, and when blood is studied at the cellular level, the magnesium deficiency then becomes apparent.

“Magnesium has also been helpful in relieving cramping that comes with menstruation,” Dr. Hunt wrote. “Two to four magnesium orotate tables every time the cramping occurs has been reported effective.

Athletes, body-builders, runners or anyone who performs strenuous exercise or physical labor should also be sure to get enough magnesium, according to Eberhard Kronhausen, Ed.D., and his colleagues in Formula for Life.

“Magnesium is responsible [together with calcium] for the production of ATP [adenosine triphosphate], our most important high-energy phosphate compound,” the authors wrote. “In addition, good magnesium levels are needed for optimal muscle contraction and to sustain the high oxygen consumption necessary for athletic performance. Research indicates that magnesium facilitates oxygen delivery to working muscle tissue, all the more reason for physical high-performers to be sure they are not held back by marginal cellular magnesium deficiency.”

Since magnesium is required for muscle contraction, and the heart is a muscle, the mineral is related to heart abnormalities and even to heart attacks. At the University of Southern California coronary care unit, researchers examined 100 consecutive admissions and found that 53 of them had low magnesium levels.

“I think that [low magnesium levels] certainly could be a contributing factor [to cardiovascular disorders],” Robert Rude, M.D., told Medical Tribune. Dr. Rude said that magnesium depletion predisposes to hypertension and cardiac arrhythmias (irregular heartbeats) and may predispose to narrowing of blood vessels and perhaps myocardial infarction (damage to heart muscle, which often precedes a heart attack).

Jean Durlach, M.D., president of the International Society for the Development of Magnesium Research, noted a consistent global pattern of magnesium deficiency and pointed out that in areas where water contains a high magnesium content, heart disease is not as prevalent.

A 1983 study from South Africa reported that every 6 mg/liter increase in magnesium levels in the water supply corresponded with a 10 percent reduction in deaths from coronary heart disease. A 1960 study found the same effect for an 8 mg/liter increase in magnesium, according to researchers at Dartmouth College.

“Moreover, in a study conducted at Glostrup Hospital, University of Copenhagen, Denmark, myocardial infarction patients were shown to have decreased levels of magnesium as judged by a parenteral magnesium retention test,” the publication reported.

Magnesium sulfate proved to be useful in reducing ventricular arrhythmias in eight patients at the Institute of Experimental and Clinical Oncology, Reggio Calabria University in Italy. No side effects were noted, according to the Journal of the American College of Nutrition.

In a study reported in the American Journal of Cardiology, 20 percent of 45 consecutive patients with atrial fibrillation (irregular heart beat) had a magnesium deficiency. Another study, reported in Critical Care Medicine, found that, of 102 consecutive patients admitted to a medical intensive care unit, 20 percent were deficient in magnesium.

Magnesium and calcium can reduce high blood pressure, according to Abram Hoffer, M.D., Ph.D., in Orthomolecular Medicine for Physicians. Dr. Hoffer maintains that 1,000 mg of calcium and 500 mg of magnesium each day will decrease the incidence of hypertension.

“A series of hypertensive patients on antihypertensive medication were given 1 gram of calcium per day,” Dr. Hoffer said. “After a few months, half of them no longer required their antihypertensive medication. Since calcium and magnesium interrelate, this means both ions are important. The incidence of hypertension is high in areas where drinking water is soft or where there is little magnesium in the soil. It has been known since 1925 that magnesium salts lower blood pressure.”

The earliest symptoms of a magnesium deficiency, according to Dr. Hoffer, include a loss of appetite, nausea, vomiting, diarrhea, mental changes and irritability. Spontaneous or induced muscle spasms and seizures may occur. Since no syndromes are specific to a magnesium deficiency, the condition often is overlooked by attending physicians, Hoffer added. Neurologic and cardiac symptoms may be associated with calcium and potassium deficiencies, as well as too little magnesium.

“Fouty maintains that magnesium deficiency should be suspected in any situations associated with potassium deficiency, even though serum levels are normal, as they are in half the subjects,” Dr. Hoffer wrote. “A few cases have been diagnosed as multiple sclerosis. A clinical background of diuretics, steroid treatment, hypercalcemia (excessive calcium in the blood), diarrhea, alcoholism, hypokalemia (potassium deficiency) and liquid protein diets should lead one to suspect magnesium deficiency.”

Dr. Hoffer added that most physicians do not realize that magnesium and calcium are intimately related and that a magnesium deficiency can cause calcium deposits in muscles and kidneys and even kidney stones in susceptible people.

“The National Academy of Sciences in the United States recommends that the average adult ingest 800 to 1,200 mg per day of calcium,” Dr. Hoffer said. “They also recommend we ingest about 350 to 450 mg per day of magnesium, i.e., they recommend a ratio of about 2 to 1, calcium to magnesium.”

Magnesium is essential for strong bones and teeth and possibly in preventing osteoporosis. Researchers reported in the Israel Journal of Medical Science that 16 of 19 osteoporosis patients had lower than normal inner bone magnesium content, as well as an overall magnesium deficiency.

Since it is not easy to get the Recommended Dietary Allowance for magnesium from foods, a supplement may be warranted.

REFERENCES:
Cohen, L., et al. “Infrared Spectroscopy and Magnesium Content of Bone Mineral in Osteoporotic Women.” Israel Journal of Medical Science, Vol. 17, pp. 1123-1125, 1981.
DeCarli, C., et al. “Serum Magnesium Levels in Symptomatic Atrial Fibrillation and Their Relation to Rhythm Control by Intravenous Digoxin.” American Journal of Cardiology, Vol. 57, p. 956, 1986.
Ensminger, Audrey H., et al. Foods and Nutrition Encyclopedia. Clovis, Calif.: Pegus Press, 1983.
Hoffer, Abram, M.D., Ph.D. Orthomolecular Medicine for Physicians. New Canaan, Conn.: Keats Publishing Inc., 1989.
Hunt, Douglas, M.D. No More Fears. New York: Warner books, 1988.
Karkkainen, P., et al. “Alcohol Intake Correlated with Serum Trace Elements.” Alcohol and Alcoholism, Vol. 23, pp. 279-282, 1988.