Magnesium is an important macro-mineral for humans that plays a role as an enzyme co-factor and as an important ion. Although the role of magnesium as a co-factor in the synthesis, utilisation and structure of the ATP molecular is well known, nutritionally magnesium has gained importance because it may protect from myocardial disease. Magnesium ions are necessary for both the structural and functional integrity of the myocardial tissue, and animals and cell culture models suggest that deficiency of magnesium may be a cause of damage to the myocardium. Studies analysing the magnesium content of hearts taken from victims of myocardial infarction show a 42% reduction in the magnesium content when compared to the magnesium content of hearts from non-myocardial related victims. Hearts from myocardial victims show only a 19% reduction in magnesium content in non infracted areas compared to controls, suggesting a threshold depletion for infarction.
There is evidence that plasma levels of magnesium are depleted in subjects admitted to hospital suffering from myocardial infarction. Further, magnesium has also been shown in animal models to prevent rhythmic changes to contraction in heart muscle as well as to protect against changes in ECG readings when animals are placed under the stress of anoxia. This protective effect may be due to the ability of magnesium to improve cardiac blood flow via an ability of Mg2+ ions to dilate the coronary vasculature bed. Clinical evidence investigating the influence of hard water on heart disease have repeatedly found a protective effect of hard water against heart disease. Strong inverse associations between the hardness of drinking water at a particular location and the rate of deaths from cardiovascular incidents have been demonstrated in a number of countries.
Although hard water contains both calcium and magnesium, researchers who have attempted to separate these variables have invariably found that the protection is afforded by the magnesium content. For example, rabbits fed a pro-artherogenic diet are protected from arterial damage when they consume hard water compared to distilled water. When the distilled water was supplemented with magnesium, the protection became just as great as with the hard water. However, supplementation of calcium to distilled water offered no improvement in protection. A comparison of men under the age of 40 from hard and soft drinking water areas after death, showed a reduced level of myocardial magnesium in men from the soft drinking water area, as well as greater evidence of myocardial disease. Studies investigating areas where drinking water has been artificially softened observed increases in the rates of death from cardiovascular disease.
RdB
