Historical review of the effects of marginal intake of magnesium in chronic experimental magnesium deficiency

K. S. Kubena and J. Durlach, Magnes Res 1990 Sep;3(3):219-26

“Magnesium and cardiovascular disease....

In the 1980s, several studies have addressed the relationship between marginal dietary magnesium intake and cardiovascular disease. The report by Altura et al.25 of microvascular changes and elevated arterial pressure associated with moderate magnesium deficiency (4.9 mmol/kg with or without 3.9 mmol Mg/litre water) in rats received a great deal of attention. They reported reduced lumen size, less blood flow in capillaries, and more vasoconstriction in rats with a marginal intake of magnesium......

.....Previously, Fischer & Giroux34 had suggested that the elevated calcium to magnesium ratio which they observed in cardiac tissue of magnesium-deficient rats (3.3 mmol/kg diet) could result in an increased contractile response in the coronary arteries and venous smooth muscles. Subsequently, coronary artery spasm could develop leading to ischaemia and arrhythmia. These researchers also stated that the increased cardiac sodium of the magnesium-deficient rats might change the membrane potential, making the heart more susceptible to arrhythmias34. Ito et al.34a observed in swine that a suboptimal magnesium intake (around half the recommended requirement) in combination with a moderate excess of Vitamin D (usual for the average American population), intensifies ultrastructural changes in the coronary arteries.....

.....Experiments with diets severely deficient in magnesium have shown that lipid metabolism is abnormal and platelet function is altered, with a predisposition to thrombosis. Moderate magnesium deficiency has the potential to be linked to an increased risk of cardiovascular disease. An elevation in serum total cholesterol which was seen in rats fed a low magnesium diet (3.3 mmol/kg) by Brilla & Lombardi35 was also reported by Luthringer et al.36 in rats fed a diet which contained the same amount of magnesium. The latter group noted hypertriglyceridaemia and a drop in high-density lipoprotein cholesterol (although hypertension did not occur in their hypomagnesaemic animals). Also of interest in Luthringer's report was the fact that vascular reactivity to noradrenaline was higher in magnesium-deficient animals. Cunnane et al.37 reported changes in fatty acid composition of diet (4.4 mmol/kg).....

....Conclusion

Information on the influence of a marginal magnesium-deficient diet is accumulating. It is clear from these studies that magnesium deficiency may be present in spite of the absence of overt signs of deficiency and may be instrumental in changes within tissues which impair function and/or promote disease.
The philosophy that absence of overt deficiency symptoms in countries with low intakes of the nutrient is an indication that the recommended levels are too high and should be reduced does not agree with evidence presented here8...”

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