Collecting data

The meta-analysis, published in the European Journal of Clinical Nutrition, used data from 22 trials looking at the effect of magnesium on blood pressure. The trials included a total of 1,173 people, lasted anywhere from 3 to 24 weeks, and studied amounts of magnesium ranging from 120 mg per day to 973 mg per day.

Magnesium makes a difference

After pooling and analyzing the data, the researchers came up with the following findings:

• Overall, taking magnesium was associated with a decrease in blood pressure.
• The average systolic blood pressure reduction (the first number in a blood pressure reading) was 3 to 4 mm of mercury, the standard unit of blood pressure.
• The average diastolic blood pressure reduction (the second number in a blood pressure reading) was 2 to 3 mm of mercury.
• In the studies that used 370 mg of magnesium per day or more, the effect of magnesium on blood pressure was greater.

“This meta-analysis showed an overall reduction in systolic and diastolic blood pressure from magnesium supplementation,” said lead study author, Lindsy Kass, of the University of Hertfordshire in Hatfield, UK. “Although the effect size was small, we know from previous research that the degree of reduction seen in these trials is likely to be clinically meaningful in terms of reducing the risks of coronary artery disease, heart failure, and stroke in a population group.”

A multipurpose mineral

If you have high blood pressure, a magnesium supplement might be a good addition to your daily routine. Here are some other reasons to consider magnesium:

• Magnesium regulates heart rhythm. Magnesium is often used to straighten out abnormal heart rhythms and keep the heart rate regular and normal.
• Magnesium might prevent angina pain. Because of its ability to dilate coronary arteries and prevent muscle spasms in the vessel walls, studies suggest that magnesium might prevent the pain associated with angina.
• Magnesium is good for muscles. From menstrual cramps to migraine headaches, and from asthma to leg cramps, magnesium’s ability to relax muscles may make it a useful supplement.
• Magnesium plays a role in regulating blood sugar. Many people with type 2 diabetes have low magnesium levels, and some studies have found that taking magnesium aids blood sugar control. Magnesium may also help prevent diabetes complications, including cardiovascular disease.
• Some drugs deplete magnesium. The most commonly prescribed medications for treating high blood pressure—diuretics—can deplete magnesium, increasing your need to supplement.

If you do decide to start taking magnesium, remember that some people experience bloating, gas, and diarrhea from taking large amounts. Taking small amounts more frequently may solve this problem.

(Eur J Clin Nutr 2012;doi:10.1038/ejcn.2012.4)