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Journal of the American Geriatrics Society
Volume 47 � Number 1 � January 1999
Copyright � 1999 American Geriatrics Society

Marco Pahor, MD, Editor



Magnesium supplementation can cause small but significant decreases in blood pressure, according to a report by Dr. Yuhei Kawano and colleagues of the National Cardiovascular Center in Osaka, Japan. The study enrolled 60 persons aged 33 to 74 years. All participants received either a daily magnesium supplement (480 milligrams) or placebo over two separate 8-week periods. The authors report that supplementation with magnesium for 8 weeks lowered blood pressure significantly. Average blood pressure reductions were small but significant. The reduction in systolic and diastolic pressure was 2.5 mm Hg and 1.4 mm Hg. The effect of magnesium on blood pressure was greater in patients with higher levels of blood pressure.

According to the researchers, patients with hypertension tend to have lower blood magnesium levels than do persons with normal blood pressure levels. Low levels of magnesium in the diet, high salt intake, alcohol intake, and taking thiazide diuretics can lead to lower levels of the element by increasing its excretion in urine. Kawano's team speculated that magnesium may help lower blood pressure through its ability to dilate the arteries. Whatever the mechanism, the authors believe that their findings support the usefulness of increasing magnesium intake as a lifestyle modification in the management of hypertension. However, they also caution that the therapeutic value of high magnesium intake may be limited because its antihypertensive effect seems to be small.

Source: Hypertension 1998;32:260-265