- Introduction
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- Magnesium is second only to potassium in terms of concentration
within the individual cells of the body. The functions of magnesium primarily
revolve around its ability to activate many enzymes.
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- Magnesium deficiency is extremely common in Americans,
particularly in the geriatric population and in women during the premenstrual
period. Deficiency is often secondary to factors that reduce absorption
or increase secretion of magnesium such as: high calcium intake, alcohol,
surgery, diuretics, liver disease, kidney disease, and oral contraceptive
use.
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- Signs and symptoms of magnesium deficiency can include
fatigue, irritability, weakness, heart disturbances, mental confusion,
muscle cramps, loss of appetite, insomnia, and a predisposition to stress.
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- Magnesium Supplementation in Cardiovascular Disease
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- Magnesium supplementation has been shown to be an extremely
effective therapy or adjunctive measure in many common conditions especially
cardiovascular disease. Magnesium is absolutely essential in the proper
functioning of the heart. Magnesium's role in preventing heart disease
and strokes is generally well-accepted. In addition, there is a substantial
body of knowledge demonstrating that magnesium supplementation is effective
in treating a wide range of cardiovascular diseases.
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- For example, magnesium was first shown to be of value
in the treatment of cardiac arrhythmias in 1935. More than seventy years
later, there are now numerous double-blind studies showing magnesium to
be of benefit for many types of arrhythmias including atrial fibrillation,
ventricular premature contractions, ventricular tachycardia, and severe
ventricular arrhythmias.
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- Magnesium supplementation has also been shown to be helpful
in angina due to either a spasm of the coronary artery or atherosclerosis.
The beneficial effects of magnesium in angina relate to its ability improve
energy production within the heart; dilate the coronary arteries resulting
in improved delivery of oxygen to the heart; reduce peripheral vascular
resistance resulting in reduced demand on the heart; inhibit platelets
from aggregating and forming blood clots; and improve heart rate.
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- Magnesium supplementation is also critical in congestive
heart failure (CHF). Studies have shown that CHF patients with normal levels
of magnesium significantly live longer than those with lower magnesium
levels. Many of the conventional drugs for CHF and high blood pressure
(diuretics, beta-blockers, calcium channel-blockers, etc.) deplete body
magnesium stores. Magnesium supplementation generally produces a modest
impact in lowering high blood pressure (i.e., less than 10 mm Hg for both
the systolic and diastolic).
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- Other Conditions Benefited by Magnesium Supplementation
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- Because of magnesium,s critical role in many body processes,
it is not surprising that research has demonstrated magnesium supplementation
to benefit many other conditions. For example, since magnesium promotes
relaxation of the bronchial smooth muscles, magnesium supplementation is
a well-proven and clinically accepted measure to halt an acute asthma attack
(via intravenous administration) as well as acute flare-ups of COPD.
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- Magnesium is known to play a central role in the secretion
and action of insulin. Several studies in patients with diabetes or impaired
glucose tolerance have shown magnesium to be of significant value. Magnesium
supplementation (usually 400 to 500 mg per day) improves insulin response
and action, glucose tolerance, and the fluidity of the red blood cell membrane.
In addition, magnesium levels are usually low in diabetics and lowest in
those with severe retinopathy. Diabetics appear to have higher magnesium
requirements.
-
- An underlying magnesium deficiency can result in chronic
fatigue and symptoms similar to the chronic fatigue syndrome (CFS). Low
red blood cell magnesium levels, a more accurate measure of magnesium status
than routine blood analysis, have been found in many patients with chronic
fatigue and CFS. Double-blind studies in people with CFS have shown magnesium
supplementation significantly improved energy levels, better emotional
state, and less pain. Magnesium supplementation has also been shown to
produce tremendous improvements in the number and severity of tender points
in patients with fibromyalgia.
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- Magnesium increases the solubility of calcium in the
urine. Supplementing magnesium to the diet has demonstrated significant
effect in preventing recurrences of kidney stones. However, when used in
conjunction with vitamin B6 (pyridoxine) an even greater effect is noted.
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- Magnesium supplementation is very important in preventing
headaches. There is now considerable evidence that low magnesium levels
trigger both migraine and tension headaches. In individuals with chronic
headaches that have low magnesium levels, magnesium supplementation has
been shown to produce excellent results in double-blind studies.
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- Magnesium needs increase during pregnancy. Magnesium
deficiency during pregnancy has been linked to preeclampsia (a serious
condition of pregnancy associated with elevations in blood pressure, fluid
retention, and loss of protein in the urine), preterm delivery, and fetal
growth retardation. In contrast, supplementing the diet of pregnant women
with additional oral magnesium has been shown to significantly decrease
the incidence of these complications.
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- Magnesium deficiency has also been suggested as a causative
factor in premenstrual syndrome. While magnesium has been shown to be effective
on its own, even better results may be achieved by combining it with vitamin
B6.
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- Available Forms:
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- Magnesium is available in several different forms. Absorption
studies indicate that magnesium is easily absorbed orally, especially when
it is bound to amino acids, aspartate, citrate, or malate. Inorganic forms
of magnesium such as magnesium chloride, oxide, or carbonate are less well
absorbed and are more likely to cause diarrhea at higher dosages.
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- Usual Dosage:
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- Many nutritional experts feel the ideal intake for magnesium
should be based on body weight (6 mg/2.2 pounds body weight). For a 110-pound
person the recommendation would be 300 mg, for a 154-pound person 420 mg,
and for a 200-pound person 540 mg.
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- Cautions and Warnings:
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- If you suffer from a serious kidney disorder or are on
hemodialysis, do not take magnesium supplements unless directed to do so
by a physician.
- People with severe heart disease (such as high-grade
atrio-ventricular block) should not take magnesium (or potassium) unless
under the direct advice of a physician.
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- Possible Side Effects:
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- In general, magnesium is very well tolerated. Magnesium
supplementation can sometimes cause a looser stool, particularly magnesium
sulfate (Epsom salts), hyroxide, or chloride.
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- Drug Interactions:
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- There are many drugs that appear to adversely effect
magnesium status. Most notable are many diuretics, insulin, and digitalis.
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- Nutrient Interactions:
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- There is extensive interaction between magnesium and
calcium, potassium, and other minerals. High dosages of other minerals
will reduce the intake of magnesium and vice versa. A high calcium intake
and a high intake of dairy foods fortified with vitamin D results in decreased
magnesium absorption. Vitamin B6 works together with magnesium in many
enzyme systems.
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- Key References:
-
- Gums JG. Magnesium in cardiovascular and other disorders.
Am J Health Syst Pharm. 2004;61:1569-76.
- Touyz RM. Magnesium in clinical medicine. Front Biosci.
2004;9:1278-93.
- Fox C, Ramsoomair D, Carter C. Magnesium: its proven
and potential clinical significance. South Med J. 2001;94(12):1195-201.
- Saris NE, Mervaala E, Karppanen H, Khawaja JA, Lewenstam
A. Magnesium. An update on physiological, clinical and analytical aspects.
Clin Chim Acta. 2000;294(1-2):1-26.
- Jee SH, Miller ER 3rd, Guallar E, et al. The effect of
magnesium supplementation on blood pressure: a meta-analysis of randomized
clinical trials. Am J Hypertens. 2002;15:691-6.
- Alter HJ, Koepsell TD, Hilty WM. Intravenous magnesium
as an adjuvant in acute bronchospasm: a meta-analysis. Ann Emerg Med. 2000;36(3):191-7.
- Barbagallo M, Dominguez LJ, Galioto A, et al. Role of
magnesium in insulin action, diabetes and cardio-metabolic syndrome X.
Mol Aspects Med. 2003;24(1-3):39-52.
- Manuel y Keenoy B, Moorkens G, Vertommen J, et al. Magnesium
status and parameters of the oxidant-antioxidant balance in patients with
chronic fatigue: effects of supplementation with magnesium. J Am Coll Nutr.
2000;19(3):374-82.
- Howard JM, Davies S, Hunnisett A. Magnesium and chronic
fatigue syndrome. Lancet 1992;340:426.
- Cox IM, Campbell MJ, Dowson D. Red blood cell magnesium
and chronic fatigue syndrome. Lancet 1991;337:75760.
- Russell IJ, Michalek JE, Flechas JD, Abraham GE. Treatment
of fibromyalgia syndrome with Super Malic: a randomized, double blind,
placebo controlled, crossover pilot study. J Rheumatol. 1995;22(5):953-8.
- Schwille PO, Schmiedl A, Herrmann U, et al. Magnesium,
citrate, magnesium citrate and magnesium-alkali citrate as modulators of
calcium oxalate crystallization in urine: observations in patients with
recurrent idiopathic calcium urolithiasis. Urol Res. 1999;27(2):117-26.
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