LOS ANGELES, CALIFORNIA. The health of the lining (endothelium) of the blood vessels is crucial to cardiovascular health. There is considerable evidence that a dysfunction of the endothelium can lead to atherosclerosis and subsequent coronary artery disease (CAD). Researchers at the Cedars-Sinai Medical Center now report that oral magnesium supplementation can substantially reduce endothelial dysfunction and improve exercise tolerance in CAD patients. The randomized, prospective, double blind, placebo- controlled trial involved 50 patients (41 men and 9 women with a mean age of 67 years) who had been diagnosed with CAD either by angiography or after having had a heart attack. Initial evaluation of the patients showed that 72 per cent of them had a lower than normal tissue magnesium level. The tissue magnesium level was measured in sublingual epithelial cells scraped from under the tongue or from between the gums and the upper or lower lips. Magnesium levels measured in sublingual cells have been found to correlate well with levels found in heart tissue.
The patients were randomized to receive either a placebo or 365 mg of elemental magnesium (in the form of oxide and carbonate) daily. After six months tissue magnesium concentration was measured again, a treadmill test was performed, and endothelial function was evaluated using ultrasound. Patients in the magnesium group increased their intracellular magnesium level by about 10 per cent to reach the lower limit of the normal range. Endothelial function (flow-mediated vasodilation measured at the brachial artery) improved by 25 per cent in the magnesium group as compared to a 4.5 per cent decline in the placebo group over the six-month period. The magnesium supplemented group also performed significantly better on the treadmill test than did the placebo group. Not only did they improve their exercise duration as compared to baseline and the placebo group, but it was also highly significant that none of them experienced an arrhythmia during the test whereas four patients in the placebo group did.
The researchers suggest that magnesium may protect the heart against the detrimental effects of a calcium overload and may improve intracellular ATP production and glucose use. They conclude that oral magnesium supplementation improves exercise tolerance and endothelial function in coronary artery disease patients. NOTE: This study was partially funded by Asta Medica Company, Inc. (Vienna, Austria) the manufacturer of the magnesium supplement.
Shechter, Michael, et al. Oral magnesium therapy improves endothelial function in patients with coronary artery disease. Circulation, Vol. 102, November 7, 2000, pp. 2353-58