In my discussions about the wide-ranging effects of Magnesium, I have found experienced clinicians and others who don't believe some of my claims. This page is an attempt to provide supporting literature references.
The presence of calcium ions is necessary to cause muscles to contract; magnesium ions are essential to induce muscles to relax:
A lower than normal dietary intake of Mg can be a strong risk factor for hypertension, cardiac arrhythmias, ischemic heart disease, atherogenesis and sudden cardiac death. Deficits in serum Mg appear often to be associated with arrhythmias, coronary vasospasm and high blood pressure (from the paper's abstract):
Hypertension can result from an increase in sodium, or a decrease in potassium or magnesium, or either an increase or a decrease in calcium:
When there is a deficiency of magnesium, the calcium must be blocked so that they still balance and you do not get the resultant muscle spasm. If the spasm is in the coronary arteries, it causes angina or arrythmia. If it's in other arteries, it causes hypertension:
Magnesium plays a major role in regulating the vascular tone (hypertension), electrical conductivity (cardiac arrythmia), and calcium deposits in blood vessels (arteriosclerosis):
Dietary magnesium (Mg) deficiency is more prevalent than generally suspected, and can cause cardiovascular lesions leading to disease at all stages of life (from the paper's abstract).
In a clinical study, magnesium was administered to 8000 surgical patients over 15 years. The results showed little or no effect on patients with low or normal blood pressure, but patients with high blood pressure usually had normal blood pressures by the time surgery was performed:
Insufficient magnesium can cause arterial calcification, which makes blood vessels hard and brittle, resulting in hypertension:
Magnesium sparing of calcium deposits has been known a long time:
Magnesium is present in many foods. Even so, only 40% of people in the U.S. consume enough to meet the RDA:
Just because you consume magnesium doesn't mean that you absorb it; low stomach acid is very common:
About 50% of body magnesium is in your bones, 49% is inside cells, and 1% is extracellular (in serum). Because of homeostasis, if your serum magnesium level gets too low, magnesium can be pumped from inside your cells into the serum. Bones are only used as a magnesium source when intracellular levels drop too low. And intracellular levels do not have to be dramatically low to induce muscular spasm.
Your kidneys can also leak magnesium. This can happen by a number of different types of chemical exposures, or perhaps more commonly, by high blood sugar levels or prescription diuretics. Diuretics also deplete potassium, which can be fatal:
The total body store of magnesium in a 70kg man is about 26000mg. About 1% of total body stores (appx 260 mg) are in extracellular fluid (serum); the rest is split between bone and intracellular stores. Assuming that you might give off a liter of sweat in a day when exercising, and that there is about 20 mg of magnesium per liter, that would be 20/260, or about 7.7% of serum magnesium can be lost in a day; a substantial loss - especially if you are already magnesium deficient:
The National Research Council has recommended minimum daily consumption of 150-250mg of magnesium for children under ten, 300mg for adult females, 400mg for adult males, and 450mg for pregnant or lactating women. If you assume a woman weighs 60kg and a man 70kg, this corresponds to 5mg/kg/day.
However, after an extensive review of the literature, one researcher concluded that an intake of 6-10mg/kg/day is optimal (that would be 360mg to 700mg/day), and also that it is a misconception that the daily requirement of magnesium is the amount that prevents signs and symptoms of deficiency or hypomagnesemia.
Regardless of the adequecy of the RDA for magnesium, the majority of people in the US have an intake of magnesium below the RDA. In 1977-78 the USDA conducted a nationwide food survey that showed a lower than recommended consumption of magnesium in the U.S. Only 25% of the surveyed population had a magnesium intake at or greater than the RDA. Almost 40% were consuming less than 70% of the RDA. Most people would agree that food quality nationwide has decreased since that time:
One of the reasons for the low magnesium intake is that when whole foods are processed, they lose about 80% of their trace minerals, including magnesium. Undiagnosed problems with magnesium absorbtion or undiagnosed renal magnesium leaks can further contribute to hypomagnesemia, even when recommended intake requirements are adequate:
Discussion of essential hypertension, with normal serum and intracellular magnesium levels:
Vasospastic angina, ischemic heart disease
Coronary heart disease, diminished left ventricular stroke volume (lower than 55%). Serum magnesium normal, intracellular magnesium significantly lower (1.59mg/dl) than healthy subject (2.11 mg/dl):
Other miscellaneous literature references: