Around 50% of all cardiac fatalities are accounted for by sudden death caused by cardiac arrest. Most of the people who have a sudden cardiac arrest are not at risk of cardiovascular disease based on the traditional risk criteria, and 55% of men and 68% of women have no clinical symptoms before death. Magnesium deficiency causes tremors, cramps, tetany and muscle spasms, and has been linked to arrhythmias in heart muscle. Its role in sudden cardiac death has been established in research and clear mechanisms exist that could explain this finding. Magnesium is an important cation in human plasma and plays an important role in the excitability of skeletal and cardiac tissue because it can activate the sodium potassium pump (ATPase). By influencing ion exchange, magnesium may have anti-arrhythmic properties and magnesium deficiency may increase the risk of the development of arrhythmias and sudden cardiac death.
For example, research published in the American Journal of clinical Nutrition in 20111 investigated the anti-arrhythmic properties of magnesium by studying magnesium intakes and plasma levels in subjects from the Nurses’ Health Study. The association between magnesium and risk of sudden cardiac death was measured in 88,375 women who were clinically free from disease. The dietary magnesium intakes were assessed by food questionnaires every 2 to 4 years and the study participants followed for 26 years. In this time, 505 cases of sudden cardiac death were recorded and a nested case control for plasma magnesium levels was performed which included 99 cases of sudden cardiac death and 291 controls. Multivariate analysis showed that the relative risk of sudden cardiac death was significantly lower in the women in the highest quartile for magnesium intake. There was also a strong linear inverse relationship between plasma magnesium and sudden cardiac death.
Magnesium is found in high concentrations in tea, coffee and cocoa, nuts, legumes, and whole grain cereals. Magnesium is part of the chlorophyll molecule and so green leafy vegetables that contain chlorophyll are also good sources of magnesium. Supplements are available in a number of mineral forms such as oxide, sulfate, chloride and citrate. Price varies between the form of magnesium, but research shows that the cheaper oxide form is absorbed and utilised by the body as well as any other form of magnesium. The processing of foods can diminish the magnesium content. For example that the refining of whole grain cereals can remove almost 80% of the magnesium content. Magnesium is generally antagonistic to calcium in the body, which explains its function as a muscle relaxant. By activating the sodium potassium pump, magnesium may activate the calcium pump and decrease intracellular calcium (the opposite of digitalis).