Introduction
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.
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.
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.
Magnesium Supplementation in Cardiovascular
Disease
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.
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.
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.
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).
Other Conditions Benefited by
Magnesium Supplementation
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.
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.
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.
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.
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.
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.
Available Forms:
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.
Usual Dosage:
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.
Cautions and Warnings:
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.
Possible Side Effects:
In general, magnesium is very well tolerated. Magnesium supplementation
can sometimes cause a looser stool, particularly magnesium sulfate
(Epsom salts), hyroxide, or chloride.
Drug Interactions:
There are many drugs that appear to adversely effect magnesium status.
Most notable are many diuretics, insulin, and digitalis.
Nutrient Interactions:
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.
Key
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Michael T. Murray, N.D., is widely regarded as one of world's leading authorities on natural medicine. A prolific author, Dr. Murray has written over 20 books on health and nutrition including the best-selling Encyclopedia of Natural Medicine and his latest book The Encyclopedia of Healing Foods. Dr. Murray is also Director of Product Development and Education for Natural Factors one of the leading manufacturers of natural products.
